Category Archives: Wellness

Exercise In Pregnancy: Elite Athletes And Regular Humans

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

In 2011, a runner here in Chicago gained some fame after completing the Chicago Marathon, then delivering her healthy full-term baby hours later.  Having gone through the heartbreak of years of infertility, I admit I felt both admiration with this woman’s accomplishment and annoyance that she would seem to take a chance with her soon-to-be-born baby’s health.

But did this person accomplish her feat while taking unnecessary or selfish risks?  As it turns out, probably not. This article is a review of current recommendations about exercise during pregnancy. Please, dear reader, remember that this article is not medical advice in any way.  If you are pregnant, please review your exercise program in detail with your obstetrician!  Every woman and every pregnancy is unique and there are specific risk factors that may lead an obstetrician to prohibit or heavily modify an exercise program during pregnancy.

It wasn’t long ago when pregnancy was treated as a disabling illness.  Women were told to be inactive and were given lengthy hospital stays with extended bedrest before and after delivery. Now, we know that this approach is not ideal for most pregnant women.  In fact, regular exercise, before, during, and after pregnancy, enhances health for most women.  Benefits of exercise during pregnancy include :

  • Reducing backaches, constipation, bloating, and swelling
  • Possibly preventing or treating gestational diabetes
  • Increasing energy
  • Improving mood
  • Improving posture, muscle tone, strength, and endurance
  • Improving sleep
  • Possibly improving the ability to cope with labor
  • Improving the capacity to get back in pre-pregnancy shape

Similar to recommendations for most healthy people, pregnant women (after having consulted with their obstetricians) are encouraged to exercise at least 30 minutes on most, if not all, days of the week.

Pregnancy has specific effects upon the body that can impact exercise.  These effects include increased mobility of joints, which can increase the risk for injury, and extra weight in front of the body, which shifts the center of gravity and can lead to back pain and decreased balance. Additionally, the extra weight (and increased volume of distribution of blood) leads to increased work from exercise. Because of these effects of pregnancy on exercise, it is best to avoid activities that demand a lot of jumping, jarring motions, or quick changes in direction and to lower expectations of intensity of exercise.  Also, after the first trimester, avoid exercise while lying supine or prone.

Preferred exercise during pregnancy includes:

  • Walking
  • Swimming
  • Cycling (preferably on a stationary bike, especially during the second and third trimesters, since balance can be affected)
  • Aerobics
  • Running (primarily for women who were runners before pregnancy)

 Exercise to be avoided during pregnancy includes:

  • Downhill skiing (because of decreased balance, the risk of physical injury, and the risk of altitude sickness)
  • Contact sports (including hockey, basketball, and soccer)
  • Scuba diving (because of the risk of decompression sickness)

Exercise during pregnancy does create specific risks to developing fetuses.   One of these risks is poor growth.  There are increased caloric needs during pregnancy (inactive pregnant women generally need 3000 calories per day) and these needs are made more complex by burning extra calories with exercise.  Therefore, it is important to follow weight and fetal development closely and make caloric adjustments accordingly.  Women who normally exercise at a high level, such as elite and professional athletes, should be especially careful to maintain good caloric intake.

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

Aside from developmental risks over time, there are risks to fetuses during exercise, itself. These risks include overheating, dehydration, and decreased blood flow to the fetus.  These are important risks, but they can generally be managed with the following recommendations:

  • Avoid exercise in hot and humid weather
  • Never exercise with a fever
  • Drink plenty of water and sports drinks
  • Avoid exerting over 90% of exercise capacity (as defined as 90% of maximal maternal heart rate)

Most of us never push ourselves to 90% or more of maximal heart rate, but elite athletes do. This last recommendation is based on a study of pregnant elite athletes who demonstrated fetal bradycardia, high umbilical artery pulsatility index, and reduced mean uterine artery volume blood flow when they exercised more than 90% of maximal maternal heart rate.  These findings appeared to be replicated in a separate study in which the pregnant athletes also exerted over 90% of maximal maternal heart rate.  In other words, at this level of exercise, the developing fetuses were stressed a great deal.

Warning signs to stop exercising and seek help include:

  • Vaginal bleeding or leaking of fluid
  • Dizziness or feeling faint
  • Shortness of breath
  • Chest pain
  • Headache
  • Muscle weakness
  • Calf pain or swelling
  • Uterine contractions
  • Decreased fetal movement

Pregnancy should not be viewed as an interruption to a fit lifestyle. In fact, exercise can be an important part of having a successful, healthy pregnancy. However, there are also important risks and warning signs to consider.  An obstetrician is the best resource to help pregnant women balance benefits and risks while planning an exercise program.  This statement is especially true for elite and professional athletes, who may need to give extra attention to such issues as caloric needs, core body temperature, hydration status, and peak heart rate.

Published April 11, 2015

Resources:

American College of Obstetricians and Gynecologists

American College of Sports Medicine

References:

Artal R and O’Toole M. Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period. Br J Sports Med. 2003;37:6-12.

Salvesen KA, Hem E, and Sundgot-Borgen J. Fetal wellbeing may be compromised during strenuous exercise among pregnant elite athletes. Br J Sports Med. 2012 Mar;46(4):279-283.

Szymanski LM and Satin AJ. Exercise during pregnancy: fetal responses to current public health guidelines. Obstet Gynecol. 2012 Mar;119(3):603-610.

Szymanski LM and Satin AJ. Strenuous exercise during pregnancy: is there a limit? Am J Obstet Gynecol 2012 Sep;207(3):179e1-179e6.

How A Medical Journal And The Medical Media Let Down The Running Community And Public Health

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

On February 3, 2015, I published an article in this blog in which I tried to carefully and fairly critique a headline-grabbing manuscript that had been published the previous day in the Journal of the American College of Cardiology.  This manuscript had, essentially, concluded that strenuous exercise is as dangerous to an individual’s health as sitting on a couch.  However, this study was statistically underpowered and relied on retrospective data (people’s memories). Therefore, it was not possible to draw conclusions about the risk of death of people who engaged in strenuous exercise.

But this was not how the medical media reported this research.  The BBC posted an article yesterday that summarized this mistake.  This article quotes earlier, erroneous, news reports:

“Training very hard ‘as bad as no exercise at all,'” reported the BBC. “Fast running is as deadly as sitting on couch,” agreed the Daily Telegraph and countless other newspapers around the world, striking fear into the hearts of hardcore runners.

So why was such an obviously weak study done, how did it get into the Journal of the American College of Cardiology, and how did it create such a public outcry?

Before reading further, it is important to explain how bias affects the creation and dissemination of information, even among intelligent well-meaning people.  Let me first explain my personal bias.  I have engaged in bench and clinical research and I have a number of peer-reviewed manuscripts to my name.  I also have written a number of review articles in medical journals.  For the last 15 years, I have reviewed medical manuscripts (in my field) for a number of highly-regarded medical journals.  Therefore, I have some credibility as a researcher who understands how research is designed and performed and as a reviewer who knows how to critique other people’s work.  I am also an endurance athlete and, therefore, may be more inclined to look carefully at a study that suggests that exercise may be harmful.

With regard to researchers, just like anyone else, they need to have jobs.  Their jobs are determined by the research funding they receive.  This funding is determined, in large part, by the quality of research they perform and the impact their research has on medicine (this is public funding, like the National Institutes of Health (NIH) in the US, not private pharmaceutical funding, which is a slightly different topic).  How does the NIH know if a researcher is performing high-quality, impactful research?  By the medical journals in which the researcher’s manuscripts are published and the attention these manuscripts receive.  Therefore, it is tremendously beneficial to a researcher’s career to publish in high-profile journals the most attention-getting material they can. But sometimes, lower-quality research can be more attention-getting.

There is an important system, however, to protect respected journals like the Journal of the American College of Cardiology from publishing bad, flashy research.  This system is called peer-review.  A typical sequence in the life of a manuscript is as follows:

  1. A researcher conducts a study, writes a manuscript about it, and sends it to a medical journal.
  2. The journal’s editor, or sub-editor, briefly reviews the manuscript for suitability to the subject matter of the journal and for obvious deficiencies (such as terrible writing).
  3. The editor or sub-editor then sends the manuscript, with identifying information like the names of the authors and sponsoring institutions removed, to one or more reviewers.  A typical number of reviewers is two, but I have seen up to four reviewers for a single manuscript.
  4. These reviewers carefully read the manuscript and then submit their opinions to the editor or sub-editor.
  5. The editor or sub-editor then reads the reviews and forms an independent opinion about the quality of the manuscript and its suitability for publication.
  6. A letter is sent to the author of the manuscript about whether the manuscript is accepted or not.  Usually, manuscripts are not accepted on a first submission, but have to go through a number of revisions that are suggested by the reviewers and editor.
  7. If the manuscript is not accepted, the author can often make revisions and re-submit the manuscript.
  8. The manuscript is then reviewed, again, by blinded reviewers (essentially going back to step 4, above).

Editors, reviewers, and publishers are human, however, and can make mistakes.  Reviews, for example, may not be performed with as much care as is necessary..  An editor may not form a separate opinion but may, instead, rely only on the reviewers to make a decision about publication.  Many intelligent reviewers don’t have a good grasp of statistics and this is an obvious area where the manuscript in the Journal of the American College of Cardiology should have been critiqued.  Reviewers are often, in fact, given permission to ask for an independent statistical review of manuscripts.  Finally, publishers want their journals seen and manuscripts cited.  This is the all-important “impact factor.”  The higher the impact factor, the “better” the journal.  This is sort of like a credit score for medical journals.  Therefore, in spite of the poor quality of this study, the buzz it created led to an increase in the impact factor of the Journal of the American College of Cardiology.

But there is another level at which poor-quality research should be filtered: the medical media. Medical journalists have specific training in reading medical manuscripts with a skeptical eye. They also, however, have deadlines and they need to publish their own material to make a living. Furthermore a headline like “running kills” or “running is as bad as couch surfing” is just too tempting to media outlets around the world, like the BBC and Daily Telegraph.  These media outlets rely on readership to survive, after all.

So, possibly because it was a controversial, flashy topic, this research study got through the filters of peer-review and medical journalists to reach the public.  This is the point at which it is important to discuss social responsibility.

When information is published on the internet, it never, ever, truly goes away.  For decades, this study and the media response to it can be taken out of context and innumerable people, who could benefit from running, may use this information as an excuse to be inactive.  The consequences to public health of sharing faulty information is immeasurable.

But here are more quotes from the new BBC article:

The lead author of the study, clinical cardiologist Dr Peter Schnohr, now concedes that he didn’t have the evidence to say that strenuous jogging is bad for you.

“We should have said we suspect that it is so, but we can’t say for sure. Everybody makes some mistakes in papers,” he says.

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

But Schnohr thinks experienced readers of research papers would have realised this – he says it was obvious from the statistical analysis that you couldn’t have confidence in the claim that strenuous joggers have the same average life expectancy as those with a sedentary lifestyle.

“It shouldn’t have been misunderstood,” he says, because if you go into the statistics the limits of the research are clear. “If you normally read papers you could say ‘Ah! This is not good statistically – this is too thin.'”

Even so, he doesn’t regret the shock-horror headlines, and isn’t worried that they might have put people off jogging.

“I don’t think so… you always have deaths in marathons and so on,” he says – and suggests that with regular check-ups, cases of heart disease may have been detected and some of these fatalities “could have been prevented”.

So the lead author of this study, Dr. Schnohr, just shrugged.

From the BBC article in which Dr. Schnohr is interviewed, it is clear that he had personal bias in designing and submitting this manuscript:

Schnohr remains convinced that although he hasn’t proved it this time, strenuous jogging might be bad for you.

Embarrasing.

Revelations like this are a great opportunity for medical journals to disassociate themselves from mistakes they have made.  Instead, as quoted again in the BBC:

The Journal of the American College of Cardiology, which published the research, stands by the paper.

“Some news articles appear to have misinterpreted and exaggerated” the story leading to “misleading headlines,” says editor-in-chief Valentin Fuster.

But the fact remains that the paper’s headline conclusion included the statistically insignificant finding about strenuous jogging – something Peter Schnohr admits shouldn’t have been highlighted.

The public is constantly subjected to information about health and it is clearly difficult, even for knowledgeable people, to differentiate between high- and poor-quality information. But if information is new and has a splashy headline, please do yourself a favor and be skeptical. Medical journals usually get it right.  The medical new media usually gets it right. But the system is not perfect.

Published April 7, 2015.

Reference:

Schnohr P, O’Keefe JH, Marott JL, et al. Dose of jogging and long-term mortality. J Am Coll Cardiol 2015; 65:411-419

Control Your Weight And Blood Sugar Through Sleep

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

Most people think they gain weight when they lose sleep simply because they have more hours in the day to eat.  This makes sense.  I remember many nights on call as a Resident at St. Louis Children’s Hospital eating large amounts of high-calorie, unhealthy food as quickly as I could.  I got into this eating pattern because I didn’t know if I would be able to eat again all night.  As it turns out, this sort of eating pattern is not the full explanation for the relationship between less sleep and more weight.  There are decades of research on this subject that have shown that good sleep, both in quality and duration, is essential to help control weight and also to prevent type II (adult-onset) diabetes.

Epidemiological (population) research has shown an association between reduced sleep and increased rates of obesity and type II diabetes.  The numbers are surprising.  For example, a study has shown that children with reduced sleep were 89% more likely to be obese.  Adults with reduced sleep were 55% more likely to be obese.  Furthermore, there is a dose relationship.  The shorter the sleep, the greater the risk of obesity.  With regard to type II diabetes, reduced sleep increased the risk of developing this disease by 28%.  For people who have difficulty remaining asleep (fitful sleepers), the risk of developing type II diabetes is increased by 84%. Interestingly, people who had “long sleep” of more than 8-9 hours a night had a 48% increased risk of developing type II diabetes.  To be clear, epidemiological associations do not prove that stimulus X causes effect Y (e.g. decreased sleep causes obesity or diabetes), but that stimulus X is associated with effect Y.  In the case of sleep and obesity or diabetes, the association appears to be very strong.

The main mechanism that appears to link reduced sleep with obesity is the actions of the two hormones, leptin and ghrelin.  These hormones help regulate the feeling of hunger.  Leptin makes people feel full, while ghrelin makes people feel hungry.  Lack of sleep leads to less production in the body of leptin and more production of ghrelin.  Consequently, lack of sleep makes people both feel less full and more hungry.  To put this concept into real-life terms, a meal that would “fill-up” someone getting 7-9 hours of sleep a night (the national recommendations), wouldn’t feel like enough for someone who only gets 5 or 6 hours of sleep a night.

There are other mechanisms whereby reduced sleep can lead to obesity.  Sleep restriction is associated with stimulation of brain regions sensitive to food stimuli.  This suggests that sleep loss may lead to obesity through the selection of high-calorie food (sleep-deprived people are more likely to grab a bag of chips than a bag of carrots, for example).  In addition, there is evidence that restricted sleep can lead to the activation of genes that promote obesity. Supporting this concept is the observation that the inheritability of increased body mass index is increased in people who get little sleep.

Sleep loss also affects how people process glucose (sugar).  Studies have shown that sleep loss leads to decreased sensitivity, of the body, to the hormone, insulin.  This hormone is responsible for helping the body to process glucose and get it out of the blood stream.  If the body detects that there is too much glucose in the blood stream, such as what would happen if there is decreased sensitivity to the effects of insulin, then cells in the pancreas, called beta-cells, respond by making more insulin.  However, in sleep-deprived people the beta-cells do not make enough extra insulin to overcome the decreased sensitivity of the body to insulin. Therefore, sleep-deprived people have decreased glucose tolerance (they cannot get rid of extra glucose in the blood stream as well as they need to) and this leads to increased risk of developing diabetes.

Another reason why sleep-deprived people have decreased glucose tolerance is brain metabolism.  The human brain consumes up to two third of circulating glucose.  However, after sleep deprivation, utilization of glucose by the brain is reduced.  Therefore, sleep deprivation leads to another mechanism whereby blood glucose cannot be processed correctly, increasing the risk for developing diabetes.

Obesity and type II diabetes are metabolic diseases that have a tremendous impact on public health and society.  The role of poor sleep, either in terms of quantity or quantity, or both, is not commonly considered in the management of these conditions.  In clinical practice, it is, therefore, important to consider improving sleep as a therapeutic tool in the management of these obesity and type II diabetes.

For those people who are starting fitness programs, those people who are struggling to reach or maintain a goal healthy weight, or experienced athletes who desire to maintain an ideal body composition, it is important to think about good sleep.  Aside from the main targets of weight control: diet and exercise, good sleep, which is defined as 7-9 hours a night for adults age 18-64, is essential.

Please see my article, “Top 12 Tips To Improve Sleep,” to help you get started.

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

Published April 4, 2015

References:

Copinschi G, Leproult R, Spiegel K. The important role of sleep in metabolism. Front Horm Res. 2014;42:59-72.

Morselli LL, Guyon A, and Spiegel K. Sleep and metabolic function.  Pflugers Arch. 2012 Jan;463(1):139-160.

Morselli L, Leproult R, Balbo M, et al. Role of sleep duration in the regulation of glucose metabolism and appetite. Best Pract Res Clin Endocrinol Metab. 2010 Oct;24(5):687-702.

 

 

16 Essential Tips To Start A Fitness Program

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

Is it tough for you to get regular exercise?

Many people feel that it is challenging to come up with an activity that seems appealing, find the time to do it, then find the time and motivation to do it again the next day, and the days and weeks and months after that.

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

The tips, below, are lessons I have learned, through 12 years of regular exercise, which has led to 50 pounds of weight loss, 8 inches off my waist, a resting heart rate of 40, and the completion of numerous endurance events, including marathons and triathlons.  I have even completed an iron-distance triathlon.  It took time because I have absolutely no athletic background, but I developed into an athlete.  Oh, and I am 47 years old, have five kids, and work full time as a physician.  It is not easy, but it can be done!

  1. Discuss your exercise program with your health care provider before beginning.  This individual knows your health status and can help you start and follow a safe program with realistic goals.
  2. Try a lot of different activities. Your goal is not to stubbornly push yourself through boring workouts for month after month.  It is important to find more than one (ideally three or four) activities that are challenging and that you can enjoy.  This will help keep the workouts fresh and, if you get sore or injured from one type of activity, it may be possible to continue with one of the other activities to maintain your fitness.
  3. Learn how to do your chosen activities well.  For example, if you want to swim, get some lessons.  If you want to lift, get some sessions with a trainer to really learn how to use the equipment safely and effectively. Youtube has a lot of how-to videos.  Bookstores and libraries are also a great resource for how-to books and videos.
  4. Do not, repeat DO NOT, buy that health club membership if you are new to exercise. Instead get a no-risk trial membership and see if you like it. This is especially true if this membership is part of a New Year’s resolution.  I have been in health clubs a lot in early January.  It can be crazy crowded.  But, in a couple weeks, it is amazing how few people remain.  Studies have shown that most people do not use their health club memberships if they buy them as part of a strategy to “force themselves” to use the memberships. Don’t misunderstand me.  I strongly support health clubs.  Just have a realistic plan and goals in mind and don’t be a “two-weeks-and-out” person.
  5. If you plan to start running, DO spend the extra money on a good pair of shoes.  Running, even for experienced runners, takes a physical toll.  Good shoes make a huge difference in protecting your body.  Consider supporting your local specialty running store.  These stores are usually the best places to find the ideal shoe for you.  Shoe selection is surprisingly complex and involves, aside from shoe size and style, the shape of the bottom of your foot, your stride length, how your legs swing when you run, the types of terrain on which you plan to run, and the distances you plan to cover.
  6. If you plan to start cycling, please get a helmet.  Decent helmets are not expensive and you will never regret having one.  I am alive today because of a bicycle helmet.
  7. Get a nice outfit if you want, but I suggest keeping it simple and inexpensive at first.  First of all, if you are new to exercise, you may find that the outfit that looks the best fits you the worst. Chafing is real!  Furthermore, you may decide that another activity is more appealing and it is just a shame to waste money unnecessarily
  8. Consider getting an exercise tracker, like a Fitbit.  I encounter people every day who are wearing Fitbits and say that they are encouraged to exercise because of them.  As I discuss in other posts in this blog, Fitbits can give reasonably accurate estimates of caloric expenditure when used within their limitations.  Studies have shown, scientifically, that exercise trackers like Fitbits can be helpful parts of fitness programs.
  9. If you are new to exercise, or coming back from a long break, start slow and easy.  National recommendations for goal levels of exercise are 150 minutes of moderate exercise or 75 minutes of vigorous exercise over the course of a week. In terms of exercise trackers, the goal is 7000 steps per day.
  10. Join a group.  Examples include a local charity walking or running group, a master’s swim group, a bike club, or a triathlon club.  Charity-oriented groups may be especially appealing to beginners because there is often free coaching and participants have non-exercise as well as exercise goals.  Online groups are another good option. Facebook is a great resource to find supportive, interactive fitness groups for just about any activity.
  11. Sign up for a race, but not a marathon if you are inexperienced.  Set a realistic goal, like a walking event and gradually build, if you want, into longer and more difficult events.  Some people only do 5K walks and runs and that is just fine.
  12. Check out fun stuff on the internet.  Youtube, for example, has an endless variety of workouts.
  13. Set small, attainable, goals rather than focusing on the “end.”  For example, your health care provider and you may decide that losing 1 pound a week over two months is a reasonable starting point.  Once you reach that goal, set new goals.  If you just focus on losing 40 pounds, you may get too frustrated.  Furthermore, once you have lost that 40 pounds, you are not “done.” Keep setting new goals. For example, after reaching your goal weight, you may want to set a goal of toning up your belly, losing a few more pounds, running a 5K, etc.  Just don’t stop trying to improve.
  14. Never turn on the television before doing your workout.  It is too easy to get sucked into the couch.
  15. Schedule your workouts as a regular part of your day, like meals and showers.  Don’t think of workouts as an interruption to your day, but just a part of the flow of the day. Believe me, you will reach the point at which, if you miss a workout, your day will feel incomplete.
  16. Embrace fitness as a lifestyle and never give up on yourself.  You will look better, feel better, perform better at work and in all aspects of your life, and you will be a role-model to your kids.

I hope this information helps and motivates you.  Please feel free to add additional tips that you have learned in the “comments” section of this page.

Be healthy and be safe!

Posted April 1, 2015

What Is Better For Your Health: Higher Volume Or Intensity Of Exercise?

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

What is better for your health, exercise more at low intensity or exercise less with higher intensity?  A number of studies have been performed to try to answer this question and one such study was published this month.  For people who are trying to lose weight and stay fit, this information should help in the planning of fitness programs.  Also, it is always important to discuss fitness programs with health care providers.

This trial was performed over 24 weeks in Ontario, Canada with 300 abdominally obese adults. The arms of the study were as follows:

  • control group of 75 individuals (no exercise)
  • low-intensity exercise group of 73 individuals (5 weekly sessions of exercise that consumed 180 or 300 calories per session for men or women, respectively, at 50% of maximum oxygen consumption) (average exercise time per session of 31 minutes)
  • high-amount, low-intensity exercise group of 76 individuals (5 weekly sessions of exercise that consumed 360 or 600 calories per session for men or women, respectively, at 50% of maximum oxygen consumption) (average exercise time per session of 58 minutes)
  • high-amount, high-intensity exercise group of 76 individuals (5 weekly sessions of exercise that consumed 360 or 600 calories per session for men or women, respectively, at 75% of maximum oxygen consumption) (average exercise time per session of 40 minutes)

The main outcomes that were measured were waist circumference and 2-hour glucose level.

Daily unsupervised physical activity and sedentary time was similar in all groups.  The three different exercise groups reduced their waist circumferences by 3.9 to 4.6 cm by the end of the study.  This was a significant difference from the control group, but there was not a significant difference amongst the three exercise groups.  The results were similar for weight loss, which averaged about 16 pounds and 5-6% of body weight.  In contrast, only the high-amount, high-intensity exercise group had a greater reduction in 2-hour glucose level than the control group. This reduced glucose level may indicate a reduced risk for diabetes, heart disease, and stroke.

Focusing on weight-loss goals only, 31 minutes 5 times a week (155 minutes per week) of low-intensity exercise achieved the same results as 290 minutes per week of low-intensity exercise or 200 minutes per week of high-intensity exercise.  National guidelines call for 150 minutes per week of moderate-intensity exercise or 75 minutes per week of high-intensity exercise.  Please note, however, that high-intensity exercise is probably defined differently between this study and national guidelines.  As a rule of thumb, I normally think that low-intensity exercise will allow maintaining an unlabored conversation, moderate-intensity exercise will lead to a good sweat, while high-intensity exercise will take some concentration and determination to maintain.

Beyond simple weight loss, for more complete health, increased intensity of exercise (if determined safe and tolerable by a health care provider) is key.  This does not have to be painful, dreaded workouts. Some simple ways to increase intensity include increasing the grade on a treadmill, increasing the amount of run vs walk during a run/walk session, increasing the resistance on an elliptical trainer or exercise bike, and tackling a hill rather than taking a flat route.  For many people, adding some increased intensity, if done carefully, also adds some fun and variety to workouts.

Be healthy and be safe.

Published March 29, 2015

Reference:

Ross R, Hudson R, Stotz PJ, et al. Effects of exercise amount and intensity on abdominal obesity and glucose tolerance in obese adults: a randomized trial. Ann Intern Med. 2015 Mar 3;162(5):325-334.

 

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

Top 12 Tips To Improve Sleep

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

The importance of sleep cannot be overstated.  Here are some tips to help you get the quality sleep you need:

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.
  1. Maintain a consistent sleep schedule with the same bedtime and wake-up time every day, even on weekends  This helps to regulate your body’s clock.
  2. Stick to a relaxing bedtime ritual that you do every night before bedtime.  This is best done away from bright lights.  This ritual helps separate your sleep time from your stressful or exciting daytime activities.
  3. If you have trouble sleeping, avoid naps, especially later in the day.  If you have trouble falling asleep, try to eliminate all naps.
  4. Exercise daily.  Vigorous exercise is best.  If you exercise late in the day give yourself enough time to relax and let your core body temperature drop before trying to sleep.
  5. Evaluate your room. Your room is for sleeping, not for work or entertainment. Remove work materials, computers, and televisions.  Your room should be cool, between 60 and 67 degrees, and free from any noise and light that can disturb your sleep.  Consider using blackout curtains, eye shades, ear plugs, and white noise machines.  Don’t forget that your restless or snoring sleeping partner can be a big disturbance to you, too.
  6. Sleep on a comfortable mattress and pillows.  Most mattresses need to be replaced after 9-10 years.
  7. Use bright light to help you manage your circadian rhythms.  For example, avoid bright light in the evening and expose yourself to bright light (ideally natural light) in the morning.
  8. Avoid alcohol, caffeine, and nicotine late in the evening, since all three of these substances can disrupt sleep.  Of course, please avoid all nicotine in general for a variety of health reasons.
  9. Remember that indigestion affects sleep.  Avoid large meals and spicy meals close to bedtime.  Ideally, give 2-3 hours between the last full meal and bedtime.  Small snacks can be okay, but try to stick to liquids.
  10. Avoid electronics before bedtime.  The screens on devices such as tablets and laptops emanate light that can be activating to the brain.
  11. If you cannot sleep, go to a different room and engage in a relaxing activity until you are ready to sleep.  This helps you to associate your bedroom with successful sleep and not frustration.
  12. If you have allergies or asthma, ask your physician for help to keep these conditions under control.  These conditions are common causes of disrupted sleep.

Modified from Healthy Sleep Tips from the National Sleep Foundation.

Image: Panneau – dormir.

Please check out the other articles on this blog about sleep and other interesting topics.

The Exercise Prescription

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

I prescribe exercise all the time to my patients.  The word “prescribe” may seem odd, but it is important.  Before starting on an exercise program, you should meet with your health care provider , to weigh risks and benefits and to help design a fitness program that is safe, with reasonable goals.  Therefore, just as a health care provider weighs the risks and benefits of any other type of treatment, exercise can be viewed as a “prescription.”  However, as so many active people know, fitness is also a lifestyle.  This article is intended as a guide to help you get started with a fitness program first as a prescription, then, most importantly, as a lifestyle. Please review any large changes in your lifestyle, such as starting an exercise program, with your health care provider FIRST!

A Position Stand from The American College of Sports Medicine was recently published and it contains a wealth of information for both health care providers and patients.  In this manuscript, experts reviewed the evidence supporting the prescription of exercise, and then gave evidence-based advice on how to “write” the prescription.

Table 1, below, was adapted from this manuscript.  There are a couple main points to highlight. First of all, evidence is very clear that engaging in regular exercise AND reducing sedentary behavior is vital for the health of adults.  In fact, sustained sedentary activity, like watching television, driving a vehicle, or sitting at a desk, can reduce the benefits of regular exercise, even if the benchmarks of exercise, discussed below, are reached.  The other main point has to do with medical evaluation before initiating an exercise program.  While the Table, below, expresses some flexibility about obtaining such an evaluation, please see my previous article on this subject which discusses my position that, in the interest of safety, planning, and support, anyone planning to start a fitness program, along with those engaged in regular exercise, should consult their health care providers.

TABLE 1. Summary of the general evidence relevant to the exercise prescription.
Evidence Statement – Evidence Category
Engaging in regular exercise and reducing sedentary behavior is vital for the health of adults. A
Training-induced adaptations are reversed to varying degrees over time upon cessation of a program of regular exercise. A
There is considerable variability in individual responses to a standard dose of exercise. A
Cardiorespiratory and resistance exercise training is recommended to improve physical fitness and health. A
Flexibility exercises improve and maintain and joint range of movement. A
Neuromotor exercises and multifaceted activities (such as tai ji and yoga) can improve or maintain physical function, and reduce falls in older persons at risk for falling. B
Neuromotor exercises may benefit middle aged and younger adults. D
Theory-based exercise interventions can be effective in improving adoption and short-term adherence to exercise. B
Moderate-intensity exercise and exercise that is enjoyable can enhance the affective responses to exercise, and may improve exercise adherence. B
Supervision by an experienced health and fitness professional and enhance exercise adherence. C
Exercise is associated with an increased risk of musculoskeletal injury and adverse coronary heart disease (CHD) events. B
The benefits of exercise far outweigh the risks in most adults. C
Warm-up, cool down, flexibility exercise, and gradual progression of exercise volume and intensity may reduce the risk of cardiovascular disease (CVD) events and musculoskeletal injury during exercise. C
Consultation with a physician and diagnostic exercise testing for CHD may reduce risks of exercise if medically indicated, but are not recommended on a routine basis. C
Consultation with a well-trained fitness professional may reduce risks in novice exercisers and in persons with chronic diseases and conditions. D
Preexercise screening Screening for and educating about the forewarning signs or symptoms of CVD events may reduce the risks of serious untoward events. C
Table evidence categories: A, randomized controlled trials (rich body of data); B, randomized controlled (limited body of data); C, nonrandomized trials, observational studies; D, panel consensus judgment. From the National Heart Lung and Blood Institute.


Table 2, below, was also adapted from the Position Stand (sections about resistance, flexibility, and neuromuscular training were edited out for the purposes of this article).  This table is especially useful because it gives goal levels of exercise as well as some useful information for people who may just be starting out.  Goal levels of exercise include 5 or more days per week (of at least 150 minutes per week) of moderate exercise or 3 or more days per week (totaling at least 75 minutes per week) of vigorous exercise.  This exercise should be regular and purposeful (a benchmark I use is breaking a sweat).  For users of Fitbits and other activity monitors, a goal is at least 7000 steps per day.  However, the expert panel also clearly stated that lower levels of exercise are still beneficial.  Furthermore: “A gradual progression of exercise volume by adjusting exercise duration, frequency, and/or intensity is reasonable until the desired exercise goal (maintenance) is attained.”  It is dangerous and unwise to try to progress quickly from being inactive to exercising 150 or more minutes per week.  Since, as stated clearly in Table 2, exercise of less volume or intensity can still give important benefits, a good approach to starting a fitness program is to start with a fairly light level of exercise and, then, gradually and carefully build.  The determination of the initial intensity of an exercise program is another area in which a health care provider can be very helpful.

TABLE 2. Evidence statements and summary of recommendations for the individualized exercise prescription.
Evidence-Based Recommendation. Evidence Category
Aerobic Exercise
5+ d/wk of moderate exercise, or 3+ d/wk of vigorous exercise, or a combination of moderate and vigorous exercise on 3-5 or more d/wk is recommended. A
Moderate and/or vigorous intensity is recommended for most adults. A
Light- to moderate-intensity exercise may be beneficial in deconditioned persons. B
30–60 min/d (at least 150 min/wk) of purposeful moderate exercise, or 20–60 min/d (at least 75 min/wk) of vigorous exercise, or a combination of moderate and vigorous exercise per day is recommended for most adults. A
<20 min/d (<150 min/wk) of exercise can be beneficial, especially in previously sedentary persons. B
Regular, purposeful exercise that involves major muscle groups and is continuous and rhythmic in nature is recommended. A
A target volume of at least 500–1000 MET/min/wk is recommended. C
Increasing pedometer step counts by at least 2000 steps per day to reach a daily step count of at least 7000 steps per day is beneficial. B
Exercising below these volumes may still be beneficial for persons unable or unwilling to reach this amount of exercise. C
Exercise may be performed in one (continuous) session per day or in multiple sessions of at least 10 min to accumulate the desired duration and volume of exercise per day. A
Exercise bouts of <10 min may yield favorable adaptations in very deconditioned individuals. B
Interval training can be effective in adults. B
A gradual progression of exercise volume by adjusting exercise duration, frequency, and/or intensity is reasonable until the desired exercise goal (maintenance) is attained. B
This approach of gradual progression may enhance adherence and reduce risks of musculoskeletal injury and adverse CHD events. D
Table evidence categories: A, randomized controlled trials (rich body of data); B, randomized controlled trials (limited body of data); C, nonrandomized trials, observational studies; D, panel consensus judgment.
From the National Heart Lung and Blood Institute.

Once you have seen your health care provider, come up with goals and a plan of how to achieve them, how do you follow through?  I think for most people this is the hardest part. From my experience, here are some do’s and don’t’s:

Do:

  • Pick an activity or set of activities that is fun and SUSTAINABLE.  It really won’t help you to do an activity for a few weeks, get bored or frustrated, and quit.  You are trying to achieve a lifestyle change and these kinds of changes are long-term.
  • Try a variety of activities, at first, to learn what you like.
  • Get a book, watch videos online, or learn from friends about how to do your chosen activity well.  It will be much more fun if you do it right.
  • Be confident that you BELONG in the gym or on the bike path.
  • Find a good group of like-minded people.  These people can be your neighbors and friends, a local club, or an online group.  I have been highly impressed with the very supportive Facebook groups: Fitbit Rules!! and the Red Tennis Shoe Group.
  • Consider signing up for a goal event, such as a 5K run or a charity walk.  The “reality” of a date on a calendar is motivating for a lot of people.
  • Smile and have fun!

Don’t:

  • Buy a gym membership on January 1st if you are not POSITIVE you will use it throughout the year.  Get a trial membership and try different things until you find out what is good for you.
  • Buy expensive gear until you learn what activities you really like.  Think sustainability!
  • Quit.  Your goal may take months or years.  Actually, if you are approaching fitness correctly, you will continue to set and reach new goals.

It is hard to go from inactivity to fitness.  But you will never regret it!

Reference:

Garber CE, Blissmer B, Deschenes MR, et al. American College of Sports Medicine position stand.  Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011 Jul;43(7):1334-1359.

 

 

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

Never Quit

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

Inactive, unhealthy

Inactive, unhealthy

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.
Active, endurance athlete

Active, endurance athlete

I read a post on Facebook a couple nights ago that broke my heart.  A young, morbidly obese, woman posted a photograph of herself sitting dejectedly in her bedroom.  She wrote: “This is me right now.  I am so depressed.”

There is an obesity epidemic right now, and there are real victims. This is not limited to the known health effects of obesity such as diabetes, cardiovascular disease, arthritis, and other medical conditions.  Obesity attacks the human psyche.

I think a large part of the reason why people find it so difficult to lose weight is that it seems to take so much effort to get such little gain.  This is why so many people make New Years’ resolutions to get fit and lose weight only to abandon these resolutions in a few weeks.  This is why so many people buy the latest diet or fitness product, but return to their previous diet and inactivity when they do not see the results they expect.

Another challenge is that many people truly cannot imagine themselves fit.  They have all seen and heard of weight loss successes, but these just don’t seem real. Models in magazines seem to come from another planet.

Obese people who are trying to get fit also face a lot of judgement and ridicule from society. How hard must it be to go to the gym or run on a public path when you don’t “look like you belong?”

Over time, in this blog, I intend to delve deeply into issues surrounding setting up a fitness program, choosing a healthy diet, and finding lifelong motivation.  This article, today, is intended to address some basic issues.

  1. See your health care provider for an evaluation and guidance before starting your weight loss and fitness program.  This topic is covered in detail in an earlier post.
  2. Unless you are making yourself sick (please don’t!!), you will probably experience only a slow drop in weight over time.  Don’t expect to reach your target quickly.  Your goal may be many months or even years down the road.  But don’t quit.
  3. Unless there are real medical barriers, most people really can lose weight and get fit.  How do I know?  I lost 50 pounds and became a multiple marathon finisher and an Ironman triathlete.  My wife lost 70 pounds and became an ultra-marathoner (that means she is one of the nutty people who thinks that a marathon is not long enough).  We were never active our entire lives until our 30s.  I am not proud of this.  I wish I were a lifelong athlete. However, our experiences help show that regular, inactive, overweight people can, truly, transform themselves into athletes.
  4. When I see overweight people at the gym or on a race course, I feel respect.  Honestly.  I have been there.  I know it is really, really hard.  I remember swimming one length of a pool and panting for a minute.  I remember running a single mile and not being able to walk down stairs for three days.  I remember lifting weights and then sitting in a locker room for 20 minutes trying not to vomit.  You don’t have to push as hard as that to be successful, but you do have to be consistent.

Your life is important.  Along with being a good, kind person, the best thing you can do for yourself and your family is to get fit.  Yes, it is hard.  Yes, it takes time.

But you will never, ever regret it!

February 21, 2015

Want To Boost Your Immune System? Get Vaccinated!

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

 

As an Allergist/Immunologist, I am asked all the time: “how do I boost my immune system?”  This is a great question and will be the subject of a number of posts to this blog.  Today, in part because of the current highly emotional media coverage of a measles outbreak, the focus will be on vaccination.  The scope of this post will be informational: how vaccines were discovered and how vaccines work within the context of the immune system.  I hope that good information of this sort will help people make informed decisions about vaccinations for themselves and their families.

The Discovery of Vaccines

The early history of vaccines and vaccination had to do with smallpox.  This viral disease is believed to have appeared around 12,000 years ago and led to large-scale epidemics.  These epidemics were so severe that they affected the course of history.  For example, the first stages of the decline of the Roman Empire, in the year 108 AD, coincided with an epidemic of smallpox that led to the deaths of almost 7 million people.  But smallpox was also a continual problem in more recent history.  For example, in the 1700s, 400,000 people died every year in Europe of the smallpox.  Aside from death, smallpox left disfiguring scars and one third of survivors lost their sight.

The original attempts at prevention of smallpox were called variolation (inoculation).  In variolation, a lancet wet with pus taken from someone infected with smallpox was subcutaneously introduced on the arm or leg of a non-immune person.  This technique was effective in inducing immunity to smallpox, but 2-3% of variolated people died from the disease, became the source of another smallpox epidemic, or were infected by another disease (such as tuberculosis or syphilis) from the pus used in the variolation.

The incomplete success of variolation led scientifically-minded individuals to begin to consider other methods of preventing smallpox.  Such a person was Edward Jenner, the “Father of Vaccination.” He, and others, had observed that dairy maids who can contracted the cowpox were protected from contracting smallpox.  On May 14, 1796, Jenner used pus from the cowpox lesions of Sarah Nelms (a dairy maid) to inoculate an 8 year old boy.  This boy was later variolated with pus from fresh smallpox lesions and he did not develop smallpox.  This is how the vaccine era began.  In fact, the term “vaccination” was invented by Jenner and was derived from the Latin words for cow (vacca) and cowpox (vaccinia).

How Vaccines Work

How did the process of injecting pus from sick people into perfectly healthy people work?  Why was the pus from smallpox lesions unsafe and the pus from cowpox lesions relatively safe?  To understand the answers to these question, it is first important to understand some basics about how the immune system functions.  Broadly speaking, we have two types of immunity: innate and adaptive immunity.  Innate immunity refers to automatic immunity.  Picture a mousetrap.  This trap will snap shut, in an automatic way, whenever the cheese in the trap is removed by a mouse. But mice find ways to outsmart the mousetrap and get the cheese, anyway.  This is the reason for adaptive immunity.  This concept refers to immunity that is learned. In other words, the immune system has components that can learn to fight off specific infections.

In the case of smallpox variolation, the adaptive immune system is exposed to the smallpox virus and, if the recipient of the variolation does not get sick and die, learns to become resistant to future infections with the smallpox virus.  Cowpox virus is similar to smallpox virus.  In fact, these viruses are so similar that the adaptive immune system, when learning to fight off cowpox virus, simultaneously learns how to fight off smallpox virus.  The big advantage, here, is that people don’t get sick or die with the cowpox virus.  Therefore, the cowpox virus works in vaccination because it mimics the smallpox virus without causing illness.

Mimicking a real infectious agent without causing illness is the fundamental concept behind every vaccine we have today.  Some modern vaccines use viruses that have been killed, and cannot cause infections, but still can allow the adaptive immune system to learn to fight the live virus.  Some other vaccines use synthetic analogs of infectious agents, but the concept is all the same.

Influenza Vaccine

Influenza virus is an annual challenge, worldwide.  Unlike the smallpox virus, which changes little over time, the influenza virus mutates as it spreads.  Therefore, every year, people need to be re-vaccinated to protect against new strains.  The World Health Organization takes the lead in formulating the components of the influenza vaccine each year.  It holds meetings in February, to recommend viruses for inclusion in vaccines for the northern hemisphere, and in September to recommend viruses for inclusion in vaccines for the southern hemisphere.  A typical trivalent influenza vaccine will contain strains of influenza A subtype H1N1, influenza A subtype H3N2, and influenza B.  In a quadrivalent vaccine, another strain of influenza B is typically added.  The selection of the strains of influenza to be used for vaccines is challenging and the match is better in some years than others.  The concept used by Edward Jenner with smallpox is exactly the same as that used for influenza vaccine: use an alternative, safer agent to teach the adaptive immune system to protect against the influenza virus, without actually causing the disease.  The technology, however, has become very sophisticated and continues to improve.  For example, older types of influenza vaccines contain inactivated influenza virus.  This is essentially “dead” virus that cannot cause influenza infection but that still contains the important elements to trigger the adaptive immune response.  More recently, live attenuated influenza vaccine has become available.  This is the well-known “nasal spray flu vaccine” and it contains virus that is live, but has been weakened so that it cannot cause actual influenza.  In January, 2013, the United States Food and Drug Administration approved a recombinant influenza vaccine.  Influenza viruses are not used at all in the manufacture of this vaccine.  Instead, a protein of the influenza virus is made by genetically modifying a virus that infects insect cells, which, in turn, produce this protein.  When this protein is used in vaccines, it can teach the adaptive immune system to resist live influenza virus.

Boosting the immune system involves making it stronger.  This concept largely has to do with teaching the adaptive part of the immune system to fight off more types of infections.  Vaccines, therefore, are a very effective way to boost our immune systems without forcing us to get sick with epidemic infections.

Posted February 7, 2015

Reference:

Riedel, S. Edward Jenner and the history of smallpox and vaccination. BUMC Proc. 2005; 18:21-25.

Resources for further reading:

www.cdc.gov/mmwr/preview/mmwrhtml/mm6332a3.htm

www.fda.gov/consumer

www.immunologyexplained.co.uk/howitworks.aspx

www.nlm.nih.gov/medlineplus/druginfo/meds/a607017.html

www.nlm.nih.gov/medlineplus/druginfo/meds/a607018.html

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

www.who.int/influenza/vaccines/virus/recommendations/201402_recommendation.pdf

 

 

Will A Lot of Running Kill You?

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
rss

A manuscript was published yesterday in the Journal of the American College of Cardiology that concluded, in a nutshell, that people who participate in strenuous running, in terms of intensity or volume, have the same rate of long-term mortality as sedentary people.   Let’s look at the study further.

This study was performed with retrospective data accumulated by the Copenhagen City Heart Study.  In this study, 1098 healthy “joggers” and 3950 healthy “nonjoggers” were followed.  9% of overall participants were age 50 or older.  Participants were excluded for a history of coronary heart disease, stroke, and cancer.  From 2001-2013, there were 28 deaths among joggers and 128 among nonjoggers (the causes of death were not recorded).  Participants rated their physical activity on a graded scale of one to four.  One: almost entirely sedentary.  Two: light physical activity 2-4 hours per week.  Three: vigorous activity for 2-4 hours per week or light physical activity for more than four hours per week. Four: high vigorous physical activity for more than four hours per week.  Joggers were further subdivided into three subgroups based on “dose” of jogging: slow (5 miles per hour, less than 2.5 hours per week, less than or equal to three times a week), moderate (5-7 miles per hour, between 2.5 and 4 hours per week), and strenuous (greater than 7 miles per hour, more than 4 hours per week, more than three times per week).

The results included the following findings:

  • Participants who ran 1-2.4 hours per week had the lowest rate of mortality.  In fact, their rate of death was 71% lower than for sedentary participants in the study.
  • Participants who ran less than 1 hour per week had a 53% lower rate of mortality than the sedentary group.
  • Participants who ran 2.5 to 4 hours per week, or more than 4 hours per week did not have a lower rate of mortality.
  • The “optimal dose” of frequency of jogging was 2-3 times per week, associated with a 68% lower rate of death compared with the sedentary group.
  • Jogging more than 3 times a week was not associated with a lower rate of mortality compared with the sedentary group.
  • Slow joggers had a 49% lower rate of death than sedentary participants.
  • Strenuous joggers had the same rate of death as sedentary participants.

Overall, the lowest mortality was in light joggers with regard to hours per week, frequency, and pace of jogging.  Moderate joggers had a significantly higher mortality rate compared with light joggers, while strenuous joggers did not have a statistically different mortality rate than sedentary participants.

This is a thought-provoking report.  But it is important to understand the limitations of the study.  For example, the data used is self-reported (by study participants) and is subject, therefore, to error.  This study is retrospective.  The best studies are prospective, in which participants are given an intervention to follow over time (light jogging, moderate jogging, etc.) and then the effects are followed.  In the case of a retrospective study, there are unknown reasons why participants end up in each group and this can affect results.  The study is also weakly powered:   there were only 47 participants who jogged more than 4 hours per week and only 80 who jogged more than three times per week.  What this means is that the number of participants in each group (sedentary, light joggers, etc.) are highly uneven and it is much more difficult to measure the statistical significance of differences between such uneven groups.  The risk of under-powering the different arms of research studies, by the way, is one more reason why a prospective design is superior.  Another weakness is the lack of reporting the cause of death.  What if, among the 28 joggers who died during the course of the study, there were 8 participants in the moderate and strenuous groups who died after being hit by cars (their rate of death, therefore, being higher because they were outdoors running for more hours and more often)?  Would the differences in the groups still be clinically significant?  Would runners, health care providers, coaches, and epidemiologists really attach much concern to such a difference in rate of mortality if it could be explained by motor vehicle accidents?  Finally, I am neither a statistician nor a cardiologist, but I am concerned about those media reports of this study that have used the term “increased risk of death.”  Retrospective data gives information about RATE of death not RISK of death.  This is a very important distinction.

So is this study wrong?

Oh no...This form doesn't exist. Head back to the manage forms page and select a different form.

Absolutely not.  I am confident that the authors gave an accurate report of the data they collected and analyzed.  My concern is about over-interpretation, in the media, of retrospective, self-reported, under-powered data, leading to changes in lifestyle.  Please let me be clear: the authors may have identified an important association between intense running and rate of death, but this study has important weaknesses.  If you want to use the results of this study, or other information you receive in the media, to alter your exercise program, please discuss your plans with your health care provider.

Published February 3, 2015

Reference:

Schnohr P, O’Keefe JH, Marott JL, et al. Dose of jogging and long-term mortality. J Am Coll Cardiol 2015; 65:411-419