It is possible to boost performance in competitions with a simple intervention: bright light.
In a paper published in 2012, researchers studied 43 male athletes with an average age of 24.5 years. This was a randomized crossover study, which is a superior study design. The participants were assessed for chronotype, which is a measurement of an individual’s internal time clock, and testing was performed either an average of 11.78 hours after estimated mid-sleep time for one group (this was the group who went to bed later and awoke later) or an average of 14.79 hours after estimated mid-sleep time for the other group (who went to bed earlier and awoke earlier). The average actual real-time of the testing was about 5:30 PM. The researchers chose this later time of day because previous studies have shown that optimal athletic performance is in the later afternoon/early evening. The study protocol involved being exposed to either bright light (approximately 4,420 lx) or dim light (approximately 230 lx) for 160 minutes. During the final 40 minutes of the ongoing exposure to different levels of light, the participants performed testing on bicycle ergometers. The finding were remarkable.
|Bright Light||Dim Light|
|Total Work||548.4 kJ||521.5 kJ|
The participants, when exposed to bright light, also had 12.7% higher levels of blood lactate at exhaustion, 1.8% higher heart rate, and 2.6% higher Borg scale ratings. Furthermore, the group that was tested three hours later with regard to mid-sleep time produced more work that the group with less time since mid-sleep. All of these differences were statistically significant.
Therefore, these researchers showed that bright light before and during endurance exercise led to enhanced performance and that exercising an average of 14.79 hours after the time of mid-sleep was superior to exercising three hours earlier.
How does this apply to amateur and professional endurance athletes? We certainly cannot pre-select our start times and almost all competitions start early in the morning. This is further complicated by the fact that most of us awaken several hours before race time and many of us creep around in the dark to avoid disturbing people around us. Furthermore, this is a single study performed under very controlled conditions. It is hard to generalize these findings to real life.
These findings, however, are compelling. My suggestion is to understand the limitations described, above, but try to apply a few of the concepts. For example, before a competition, try to be in brightly lit areas for the greatest duration possible. Many competitions start in the semi-darkness of early dawn, but getting a boost of light before lining up to race, just like eating the right pre-race meal, may enhance performance.
Published March 9, 2015
Kantermann T, Forstner S, Halle M, et al. The Stimulating Effect of Bright Light on Physical Performance Depends on Internal Time. PLoS ONE. 2012 7(7):e40655.