Based on the available research, evidence suggests that exercise does, in fact, help you fall asleep faster and stay asleep longer. However, strenuous exercise beyond your normal training regimen, does activate your body’s natural stress response. When you work out, adrenaline and cortisol are released, which can affect sleep latency and sleep quality. Therefore, it’s not really a matter of too much exercise, but when you work out and how physically fit you are, that can affect sleep.
Can Exercise Help Treat Insomnia
Researchers do not truly know what the direct mechanisms are of how exercise can help treat insomnia. However, based on the available research, they do have some solid theories.
In a systematic review published in the Journal Clinics, several prospective studies investigating the effects of exercise as an alternative treatment for insomnia, concluded that exercise is in fact effective in treating chronic insomnia and improving sleep quality [R].
Exercise has an anti-anxiety or anxiolytic effect, which helps you achieve a state of wakeful relaxation needed to fall asleep faster and stay asleep. Sleep supplements such as ZMT, which use proven sleep ingredients and adaptogens such as GABA, theanine, valerian root, and tryptophan, use a similar mechanism.
While researchers are still investigating exactly how physical activity impacts sleep, they have found that moderate exercise is the most effective at relieving insomnia.
Researchers have found however, that regardless of time of day, engaging in resistance exercise does help improve sleep quality. Observations reported that variations in the timing of resistance exercise affected aspects of sleep. For example, morning exercise was found to significantly improve the time required to fall asleep, and evening exercise was found to significantly reduce wake time after sleep onset.
Can Too Much Exercise Cause Insomnia
The short answer to this question, is no. Well not really. Some people however, do experience exercise induced insomnia, if they train to close to their bedtime, while others have no trouble falling asleep.
As I mentioned, researchers have found that moderate exercise is best for insomnia. Strenuous exercise beyond your normal exercise capacity does activate the stress response systems, including the release of cortisol, adrenaline, and endorphins.
The body secretes adrenaline and another inhibitory neurotransmitter, norepinephrine, in response to exercise. These hormones increase heart rate, glucose metabolism, mental alertness, and blood flow. Meaning, that if you work out to close to bedtime, you might have a hard time relaxing and falling asleep.
The amount of these hormones in your blood stream depends entirely on the intensity and duration of your exercise. It also depends on your level of training. In other words, if you are not as physically fit, and you decide to add an extra high-intensity workout, or cycle longer than usual, your veins will be coursing with more adrenaline and norepinephrine than someone who is more physically adapted.
In addition, endurance exercise and resistance training, triggers the release of cortisol, your body’s natural stress hormone. Cortisol plays an integral role in sleep-wake cycles. Studies report that those who are affected by sleep disorders, such as insomnia or obstructed sleep apnea, have elevated cortisol levels [R].
Cortisol levels rapidly rise in the middle of the night, peaks in the morning, and hits a low when you are getting ready to go to sleep. Cortisol is released in a pulsatile manner, throughout the 24-hour day, and decreased during slow-wave sleep [R].
Your body’s natural response to more physical stress, is elevated cortisol levels. Therefore, a strenuous workout, will in fact elevate your cortisol levels and likely disrupt you’re your cycle. Instead of rising when you wake, and gradually falling when you sleep, your cortisol levels remained elevated throughout your workout.
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For some people, working out later in the day despite workout intensity, does not affect their sleep. However, if you are having trouble sleeping, you might want to consider shifting your training schedule to give your body time for the effects of your hormones to wear off.
Can Exercise Affect Sleep And Cause Insomnia: Takeaway
The bottom line is that moderate exercise and training can in fact, help sleep and sleep quality. Working out to close to your bedtime, however, can and may interrupt sleep cycles, which can contribute to exercise induced insomnia.
Despite the overwhelming evidence that sleep, and exercise are both sufficient for overall health and pivotal in physical fitness, they are often deprioritized. If you have trouble sleeping, due to exercise, simply reevaluate your training times and stimulant intake. So long as you do engage in moderate physical activity, your sleep will and should improve.