Exercise and Sleep
Exercise and balanced day-night rhythms go hand in hand and are strongly connected. Being physically active makes you feel energetic during the daytime and improves your sleep the following night. Many studies have found that people who are active and exercise on a regular basis feel less tired than people who exercise very little or irregularly. They also fall asleep easier and report better quality of sleep.
The relationship between sleep and exercise has been studied extensively, but researchers are still not quite sure why physical activity has such a significant positive effect on sleep. Likely numerous indirect mechanisms are involved, and no sole reason can even be found. Humans are diurnal animals meaning we are inherently active during the daytime and prefer to sleep at night. It's only natural that our bodies endorse this behavior.
The human body is built to sustain physical activity the whole day. The ability to hunt, travel, and flee, whenever needed, was essential for our early ancestors in the African savannas. Therefore in terms of health benefits, the timing of the exercise is not really important. It doesn't matter whether you prefer to exercise, for example, early in the morning or late afternoon. However, the timing might have some effect on your circadian rhythm, alertness, and physical performance. For instance, an early morning training session can help you beat morning tiredness and sleep inertia symptoms and kickstart your day with a boost of energy. Or if you are more of an evening type of a person, exercising late in the afternoon might be more of your thing. The decreasing body temperature after an early evening workout can have sleep-promoting effects. Even the tiniest improvement in daily activity levels can have a significant impact on your sleep. So why not start today?
Most of the time, physical activity increases the quality of your sleep. However, a heavy training session late in the evening can disrupt your sleep quality and ability to fall asleep if your body doesn't have enough time to wind down after the activity. This might not be an issue for young individuals, but the older you get, the more time your body needs to recover. We recommend listening to your body and be honest with yourself. Is the 10 pm time slot really the only one available for that heated workout session, or could it be rescheduled a couple of hours earlier? However, don't use this as an excuse for not working out at all. Here is a general rule of thumb for you: regardless of the situation, it is almost always better to exercise than not to.
Habits From This Lesson
Buman, M. P., Phillips, B. A., Youngstedt, S. D., Kline, C. E., & Hirshkowitz, M. (2014). Does nighttime exercise really disturb sleep? Results from the 2013 National Sleep Foundation Sleep in America Poll. Sleep Medicine, 15(7), 755–761.
Driver, H. S., & Taylor, S. R. (2000). Exercise and sleep. Sleep Medicine Reviews, 4(4), 387–402.
Loprinzi, P. D., & Cardinal, B. J. (2011). Association between objectively-measured physical activity and sleep, NHANES 2005-2006. Mental Health and Physical Activity, 4(2), 65–69.