Effects of Exercise on Sleep

Original Editor - Sai Kripa

Top Contributors - Sai Kripa, Pacifique Dusabeyezu, Kim Jackson and Sehriban Ozmen  

Introduction

Sleep

Sleep is defined as a reversible state where your responsiveness to external environmental stimuli is reduced. We can divide sleep into two sleep states, namely rapid eye movement (REM) sleep, and non-rapid eye movement (NREM) sleep. While sleeping at night there is a sequential rotation occurs quite a lot of times (5 to 6 times) among these two sleep states. According to the American Sleep Association, there are many sleep disorders that humans suffer from; including dyssomnias such as Sleep Apnea, Hypersomnia, and Insomnia; Bruxism; parasomnias such as REM Behavior Disorder and sleepwalking, and circadian rhythm sleep disorders. Furthermore, sleep disorders are so common among individuals and it could lead to chronic sleep deprivation which is completely dangerous. There are numerous pharmacological interventions available to treat these sleep disorders, however, one of the best non-pharmacological interventions approved by the American Sleep Disorders Association regarding improving your sleep is considered to be Exercise. Wide epidemiological studies indicate the therapeutic advantages of moderate to regular physical activity regarding sleep. Also, researchers can conduct various studies among the population to identify the effects of exercise on sleep quality and quantity. Since shreds of evidence can find the physiological and psychological calming effects of exercise that are well known, which it could be obvious to assume that exercise can promote sleep.

Does Exercise Reduce Sleeplessness?

Exercise is a variety of physical fitness that mainly withstand physiological stress. Many would have told us that exercising regularly is good for your mind and body. However, preferences of choosing for exercises extremely vary among individuals. Some individuals might prefer doing exercises regularly, while others might prefer to avoid exercises fully. Here, our actual concern is to understand the relationship between exercise and sleeplessness and whether exercise should be a part of the prescription for people suffering from sleeplessness. To identify the effect of exercise among insomniacs, two types of research have been performed which mainly showed improvement among individuals and encouraged them to sleep.

Sleep plays a crucial role in promoting memory consolidation and learning as well as allowing the body to recover and restore itself. Unfortunately, many people face issues such as insomnia, sleep apnea, and restless legs syndrome that disrupt their sleep. However, physical activity can be a helpful strategy to enhance sleep quality and decrease the risk of sleep disorders, as it has a positive impact on sleep quality.

Regular physical activity can improve your sleep quality in several ways. Firstly, it boosts the production of melatonin, a hormone that regulates the sleep-wake cycle of the body. This helps you fall asleep faster and enjoy better quality sleep. Secondly, physical activity helps reduce stress levels, which is a common barrier to falling and staying asleep. Thirdly, engaging in physical activity improves your mood, leading to increased enthusiasm for exercise and creating a positive feedback loop. Research shows that physically active individuals have higher levels of positive emotions and tranquility during exercise, and lower levels of negative emotions and tiredness. Finally, physical activity helps regulate body temperature, which is necessary for falling asleep. An increase in body temperature during exercise aids in the eventual drop 30-90 minutes post-exercises, facilitating easier sleepiness.

According to studies, engaging in regular physical activity can enhance the quality and duration of sleep. Scientific literature suggests that adults who exercise for at least 30 minutes a day tend to sleep for an average of 15 minutes longer than those who do not exercise.

By looking into the above-proved evidence, we can say that exercise can help improve the sleep quality of people suffering from sleeplessness and exercise should be a part of the daily routine for every individual for healthy benefits

Impact of Acute & Chronic Exercise on Sleep Disorders

There are numerous non-pharmacological interventions available to treat sleeplessness, such as relaxation therapy, sleep hygiene techniques, and sleep restriction therapy. However, some researchers suggest that acute morning exercise can effectively improve sleep quality among individuals. The relationship between exercise and sleep has been extensively studied, with many people relying on exercise as an alternative or adjunct to traditional sleep-related therapies. Exercise has been shown to reduce the risk of cardiovascular diseases, promote overall fitness, reduce mortality rates, and improve mental health. By identifying the potential effects of exercise on sleep, individuals can make informed decisions about managing sleep-related disorders without relying on medication, which can have negative side effects..

A study investigates the effect of acute exercise on good sleepers and they can use Polysomnography to assess sleep. The parameters that are focused for examination include sleep onset latency (SOL), stage 2 sleep, SWS, rapid eye movement (REM) sleep, REM latency (REM-L), total sleep time (TST), and wakefulness after sleep onset (WASO). We can observe little to moderate effects on SWS, REM, REM-L, and TST. Nevertheless, the research has focused completely on good sleepers; as even sleeping pills could bring a difference to good sleepers, we are unable to identify the variation in the magnitude of effects of exercise on sleep among people suffering from sleep disorders due to lack of evidence.

In a pilot study, researchers investigated the impact of acute aerobic exercise on 17 young females. They were instructed to use the treadmill for 30 minutes, maintaining a heart rate reserve of 65%-88%. The study used worry, anxiety, feelings of energy, and fatigue as outcome measures. The results showed a moderate to large decrease in anxiety and fatigue levels, as well as an improvement in feelings of energy. This provides evidence supporting the positive effects of acute aerobic exercise on individuals with generalized anxiety disorder.

Similarly, looking for the evidence regarding chronic exercise on sleep, there is an absolute increase in parameters such as TST, and SWS and a decrease in sleep onset latency, REM sleep, and WASO. Chronic exercise provides extreme benefits to older people suffering from sleep disorders. Besides, controlled studies prove that individuals who are suffering from sleeplessness and anxiety can see improvement post-chronic exercise. However, these studies are limited to self-reported measures and further researches are required to find the benefits of chronic exercise on sleep.

Theories behind Exercise Influencing Sleep

There are numerous findings regarding the positive effects of exercise towards good sleepers however, there is less evidence to prove the efficacy of exercise on sleep sufferers. Furthermore, future research is required to identify the role of acute and chronic exercise on sleep. On the other hand, we could be able to see some misconceptions & predicted positive hypotheses towards the effects of exercise here, which will help us to gain knowledge regarding the exact working mechanism behind exercise promoting sleep among the population.

Thermoregulation

When an individual performs exercise or intense physical training, their body experiences vasodilation resulting in increased blood flow to the skin, which in turn increases body temperature and promotes sleep. The Anterior hypothalamus plays a crucial role in regulating the body temperature and promoting sleep before bedtime. After exercise, when the body temperature rises, sweating increases, and metabolic rate decreases, resulting in a decrease in body temperature during sleep. According to the thermoregulatory hypothesis, exercise needs to be intense enough to raise the body temperature for it to have a positive effect on sleep. Low-intensity exercise doesn't provide any benefits to sleep. Besides active exercises, research also suggests that passive methods such as sauna baths or hot tubs can also promote SWS. Therefore, evidence suggests that there is a clear connection between temperature regulation and increased sleep..

Exercise before bedtime

Time of exercise is the most important parameter here that could have an acute effect on sleep. There are common questions that usually arise among individuals regarding the perfect time for performing the exercise. Individuals believe that performing exercise before going to sleep can hurt their sleep. However, observing the findings from research has proved doing exercises 2 hours before going to sleep can improve the quality of sleep among individuals or have no effect on others. Another recent evidence shows that performing a 1-hour session of exercise at 60% VO2 max or a 3-hour session of exercise at 70% VO2 max by aerobically fit individuals 30 minutes before going to sleep did not affect the sleep quality.

Exercise Duration

It is necessary to know the duration of exercise before commencing with any exercise protocol. When talking about the effect of exercise on sleep, it is required to know whether performing exercises for how long may perhaps bring a reliable effect among individuals. A meta-analytical study shows that exercise increases SWS, reduces REM sleep, and delays REM latency in already fit individuals. We can see the effects of an actual increase in sleep changes when individuals perform exercise longer than 1 hour a day. However, further research is required to know, if performing exercise for longer periods will bring an improvement in sleep quality in individuals.

Exercise and Fitness

We can say that physical fitness is achieved when we consume appropriate nutrition, perform moderate to vigorous exercises, and have adequate rest. If an individual is not able to fulfill these criteria, he/she is falling sick, has a low energy level, suffering from disease and hopelessness we consider them unfit. There are a few researches suggest that a vigorous level of exercise can help in improving sleep quality. However, there is a misconception that fit individuals can only perform vigorous intensity exercises, rather unfit individuals and they can be able to benefit from such exercise for sleep. An experimental study proved this statement wrong, and suggests, that there is no role of fitness with regards to exercise & sleep and such findings indicate that exercise encourages sleep in a wide range of the population.

Exposure to Outdoor light

Appropriately, timely exposure to bright light can enhance sleep quality among the population. Individuals going out and receiving bright light for more than 2,500 lux for almost 20 minutes, 3 times a day could help in increasing the sleep as much as possible more than exercise.

Anti-Depressant effects

Sleep disturbance is one of the most common characteristic features among individuals suffering from anxiety. According to evidence, the findings can prove that anxiolytic therapeutic therapies are effective in treating patients suffering from sleeplessness.  Moreover, speaking about exercise, researchers are also able to show that exercises are effective in reducing anxiety by providing psychophysiological treatment effects. It promotes better control between the mind and body and helps in improving the conditions and symptoms of patients suffering from anxiety. Possibly, exercise could promote better sleep by reducing anxiety symptoms. Apart from that, evidence also suggests that individuals suffering from sleeplessness are more prone to developing depression. Thus, findings support that chronic exercise can encourage sleep by promoting anti-depressant effects and reducing depression. There is an observable reduction in REM sleep due to acute exercise and such reductions can be found in anti-depressant treatments.

Conclusion

Regular exercise is beneficial for those with sleep disorders as it reduces worry, anxiety, and depressive symptoms, leading to improved sleep quality. Moderate-intensity physical activities are effective in managing sleep disorders like insomnia, while high-intensity activities, especially in the evening, may lead to difficulty sleeping. Factors affecting the effectiveness of physical activities include gender, age, activity type, timing, duration, and consistency. Promoting regular physical activity can improve sleep health and overall well-being.