# 40 - Sleep and Exercise Pt. 2
This week, Matt goes deeper into the relationship between sleep and exercise. More specifically, does daytime exercise change the stages and types of sleep? Deep sleep is critical for various functions, so anything that can increase it is desirable. Older adults have an inherently difficult time generating deep non-REM sleep; however, a study showed that the amount can shoot up by 40% following a day with modest exercise. Moreover, it indicated that participants’ cognitive functioning was significantly sharper following that night of exercise-enhanced deep sleep.
Exercise in healthy young adults also stimulates a lush increase in deep non-REM slow brainwave activity, up to 50% in the first part of the night. However, that exercise must be more vigorous to see a consistent, substantive, increase in deep non-REM sleep.
However, there is a footnote to this good news: most of these studies saw a modest but reliable decrease in the amount of REM sleep the night following exercise. This isn’t a surprise for sleep scientists like Matt, who were already aware of some reciprocity between these two types of sleep, which seem to push and pull at each other’s levels. Why this reduction in REM sleep happens with a dose of acute, one-shot exercise and what the consequences are remains unexplored. Matt’s hypothesis is that it occurs because, in many of these studies, the total amount of time in bed is fixed. He suspects that if individuals were left to sleep as much as they wanted, they would sleep a little longer and thereby get the same amount or even more REM sleep.
Ultimately, the question becomes this: is regular exercise effective for maintaining and improving good sleep, or does its potency gradually wear off ? Thankfully, the answer is that regular, consistent exercise does benefit sleep, and the improvements it provides don’t get fade over time. Indeed, a meta-analysis approach teaches us that regular exercise has four persistent benefits, 1) improving sleep efficiency, 2) an increase in the amount of sleep achieved, 3) an increase in the speed of falling asleep, and 4) improvement in the quality of sleep experienced.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
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As always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.