Exercise, light exposure and sleep quality

The greatest and most prevalent risk factor for sleep apnea is excess weight. Therefore, sleep apnea can be minimized or even “cured” with weight loss. This is, of course, easier said than done. If you are somebody who has a hard time losing weight with exercise, is exercising still worth it? A recent study examined the effects of exercise on sleep, independent of weight loss.

The research team, based in Korea, had 10 participants undergo four separate conditions: light exercise for 30 minutes without any light exposure, light exercise for 30 minutes with light exposure, 30 minutes of light exposure, and neither light exposure nor exercise. Each 30-minute session was repeated 5 times per week, with one week of “wash out” (no conditions) for a week between each condition. Throughout the entire protocol, each participant completed a survey that included bedtime, wake-up time, and sleep onset latency (how long it took them to fall asleep). What’s more, melatonin (a sleep-regulating hormone) was monitored via blood draws.

Results showed that those in the condition where the participants did not exercise or have sun exposure had the latest bedtime (which is a bad thing!). Wake time, in effect, was also later for that condition. What’s more, reported sleep quality was lower during the no-exercise and sun condition when compared to the exercise + sun condition. Melatonin concentrations were found to be higher during the exercise + sun condition than the no exercise or sun condition. 

So should you exercise? This study suggests that your sleep quality is indeed improved by exercise. What’s more, it seems exercise + sun exposure has the greatest effects on sleep quality. Ideally, then, you would be exercising outside. But if you are like most of us, you may not live in a climate that allows for outside exercise. In that case, as this study suggests, exercise – even without light exposure – is still beneficial for sleep. For you apneics out there, you should be doing anything that can improve your sleep quality! So even if you are not losing weight, exercise is still helping! 

Lee, H., Kim, S., & Kim, D. (2014). Effects of exercise with or without light exposure on sleep quality and hormone responses. Journal of Exercise Nutrition & Biochemistry, 18(3), 293.

Janna Mantua


Janna is a PhD Student / Graduate Research Assistant at University of Massachusetts Amherst with a background in clinical sleep research and psychology. Janna Mantua is a PhD student in the Behavioral Neuroscience department at the University of Massachusetts. Her research focuses on sleep and aging, with specific projects on cognitive health, inflammation, memory formation, and neuroimaging. Prior to her PhD work, Janna was involved in research on sleep apnea and cognitive decline at the NYU Sleep Disorders Center.

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