New research is challenging the old belief that you should exercise at night because it disrupts sleep.

For many decades, we have been advised against nighttime exercise because it is too stimulating and would disrupt our normal sleep architecture. But now, according to new research, this is being turned on its head, and we need to view late-night exercise in an entirely new manner. Now we need to consider both the timing and the intensity of exercise and its effect on sleep.

Studies have shown that exercising at night improves sleep quality. However, very few studies have examined the effects of strenuous exercise compared to moderate-intensity exercise on sleep quality. Therefore, studying the effects of exercise intensity on sleep quality and whether it varies between morning and evening workouts is crucial.

The quality of sleep varies. Each night’s worth of sleep is actually made up of multiple cycles of the four-stage sleep cycle. A normal night’s sleep comprises four or six cycles. First, there is rapid eye movement (REM) sleep, and second, there is nonrapid eye movement (NREM) sleep, further divided into three stages: N1, N2, and N3. Eye movements, brain wave patterns, and muscle tone all change throughout the stages of sleep. About four or six times per night, the body goes through all phases for an average of ninety minutes each cycle.

The mystery of all of this lies in the sleep-related hormone, melatonin. There is mounting evidence that exercise can affect melatonin secretion in humans and that these effects can be either immediate or delayed.

Exercise can change melatonin levels quickly (within minutes) and cause a shift when melatonin is released into the bloodstream at night (12 to 24 hours later). Acute and delayed effects seem to be time-dependent.

The length, intensity, and kind of exercise also determine whether an immediate effect is detectable. Exercise may reduce melatonin levels during the rising phase of melatonin release, which occurs in the late evening.

Research shows that mood is uniquely influenced by a person’s level of physical activity and sleep. These two factors appear to be at least somewhat independent. Light and moderate-to-vigorous exercise produced more NREM sleep, less REM sleep, and a longer REM-L latency. After a longer REM-L period, participants reported less stress and more energy the next day.

A total of 23 studies were reviewed by the researchers, all of which compared healthy adults who exercised once in the evening to those who did not in terms of when and how well they slept. Exercise in the evening not only had no effect on sleep quality, but it also appeared to hasten sleep onset and increase the time spent in deep sleep.

People whose high-intensity workouts (such as interval training) were done less than an hour before bedtime had worse sleep quality and a harder time falling asleep.

The moral of the story is that you should include regular exercise in your list of healthy sleep hygiene routines, regardless of the time of day. Just remember to avoid intense physical activity in the late evening.

What to Do?

Several things you can do to help yourself get restful sleep include:

1. Developing a soothing habit before bed can help you get a better night’s rest.
2. You should turn off all light-emitting electronics, including the TV, computer, and phone, at least half an hour to an hour before you want to go to sleep.
3. Make sure you have a cool, dark, and comfy bed and that your bedroom is free of noise.
4. Avoid taking lengthy naps during the day. If you need to nap, do not sleep for over twenty to thirty minutes in the early afternoon.
5. At night, after fifteen to twenty minutes and you still have problems getting to sleep, try sleeping in a different room.
6. Find a quiet place to read in the dark until you nod off.

Therefore, the multiplicity of studies points to the benefits of regular exercise and the times of this exercise for optimum sleep quality, stress reduction, and mood improvements. Do exercise and avoid becoming stagnant in your daily life. The sleep you achieve will be well worth the effort if you practice the simple steps advised by many sleep researchers.