Effects of Exercise on Sleep

Original Editor - Sai Kripa

Top Contributors - Sai Kripa and Kim Jackson  

Introduction

Sleep

Sleep is defined as a reversible state where your responsiveness to external environmental stimulus is actually reduced[1]. We are able to divide sleep into two sleep states, namely rapid eye movement (REM) sleep, 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[2]. According to 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 intervention approved by American Sleep Disorders Association regarding improving your sleep is considered to be Exercise. Wide epidemiological studies indicates the therapeutic advantages of moderate to regular physical activity in regards to sleep[3]. Also, researchers are able to conduct various studies among population to identify the effects of exercise upon sleep quality and quantity[4]. Since evidences are able to find the physiological and psychological calming effects of exercise that are well known, due to which it could be obvious to assume that exercise can promote sleep[5].

[6]

Does Exercise reduces 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 on regular basis, while others might prefer to avoid exercises fully. Here, our actual concern is to understand the relation present between exercise and sleeplessness and whether exercise should be a part of prescription for people suffering from sleeplessness. In order to identify the effect of exercise among insomniacs, two researches have been performed which mainly showed improvement among individuals and encourage to sleep.

A 4-week non-pharmacological therapy session performed on target population suffering from psychophysiologic insomnia included various interventions. Providing education to people regarding sleep hygiene, focusing on sleep-wake timetable of people by inspiring them to sustain a proper preset timetable and pay no attention to diurnal nap or not to sleep during the day. Further, phototherapy follows people to sit opposite to bright light with 3,000 lux for approximately 45 minutes just after waking up from sleep. Apart from all these, going for evening fast walk in the early hours proved that exercise is extremely helpful for people suffering from sleeplessness. We can see an improvement in sleep due to people exposing themselves to outside light during their exercise or other daytime period. Furthermore, considering people’s expectations about improvement in sleep linked with each intervention provided can also be one of the factors apart from outdoor exposure [5][7].

Similarly, a randomized sample of 43 people with mean age of 50-76 yrs with target population complaining about moderate sleep performed 30-40 minutes of moderate aerobic exercise during daytime or in the early evening hours for 4 times/week. It was a complete 16 weeks exercise session. Pittsburgh Sleep Quality Index was an outcome measure used to assess the sleep quality of individuals following the complete exercise session proved the effectiveness of exercise on sleep with people suffering from sleeplessness[5][8]

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

Impact of Acute & Chronic Exercise on Sleep disorders

There are so many non-pharmacological interventions to treat sleeplessness such as relaxation therapy, sleep hygiene technique and sleep restriction therapy. However, according to few researches there are so many anticipations regarding effectiveness of acute morning exercise on improving sleep among people, The expectations about exercise towards sleep among sleep population are unbreakable over the years. As exercises are extremely helpful in decreasing cardio vascular diseases and promote fitness, decrease death rate, apart from that it also promotes mental health. Usually, people avoid consuming sleeping pills as it has its own negative side effects due to which they pick on exercise, an alternative or adjunct management for sleep related disorders.  Therefore, it is actually required to identify if exercise has any effect on sleep[9].

A study investigates the effect of acute exercise on good sleepers and they are able to use Polysomnography to assess the 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 are able to 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 difference to good sleepers, we are unable to identify the variation in magnitude of effects of exercise on sleep among people suffering from sleep disorders due to lack of evidence[5].

A pilot study examines the effect of acute aerobic exercise on 17 young females by instructing them to perform treadmill for 30minutes at 65%-88% heart rate reserve. Worry, anxiety, feelings of energy and fatigue are the outcome measures used. We are able to observe moderate to large decrease in anxiety level and fatigue, along with improvements in feelings of energy. Evidence promotes positive effects of acute aerobic exercise on people suffering from generalized anxiety disorder[10]

Similarly, looking for the evidences regarding chronic exercise on sleep, there is an absolute increase in parameters such as TST, SWS and decrease in sleep onset latency, REM sleep and WASO. Chronic exercise provides extreme benefit to older people suffering from sleep disorders. Besides, controlled studies prove that individuals who are suffering from sleeplessness and anxiety are able to see improvement post chronic exercise. However, these studies are limited to self-reported measure and further researches are required to find the benefits of chronic exercise on sleep[11].

Theories behind Exercise Influencing Sleep

There are numerous findings regarding 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 hypothesis towards effects of exercise here, which will help us to gain knowledge regarding the exact working mechanism behind exercise promoting sleep among population.

Thermoregulation

If we talk about the thermoregulatory process, during an individual performing exercise or gets indulge in an intense physical training, there occurs vasodilatation leading to increase in blood flow to the skin and rise in body temperature that promotes sleep. The Anterior hypothalamus plays an important role in regulating the body temperature (heat loss) and promoting sleep before bedtime. When there is an increase in body temperature post-exercise, there will be an increase in sweating along with decrease in metabolic rate and body temperature during sleep. On considering thermoregulatory hypothesis, exercise has to be intense enough to increase the body temperature, to enhance increase in sleep; low-level intensity exercise would not provide benefit to sleep. Apart from active exercises, findings also prove that passive methods such as sauna bath or hot tub would also promote SWS. Therefore; evidences suggest that there is clear connection among temperature regulation and increase in sleep[5].

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 have a negative impact on their sleep. Though, on observing the findings from research has proved doing exercises 2 hours before going to sleep can actually improve the quality of sleep among individuals or have no effect for others. Another, recent evidence shows that performing 1 hour session of exercise at 60% VO2 max or 3 hours session of exercise at 70% VO2 max by aerobically fit individuals 30 minutes prior going to sleep did not affect the sleep quality[5].

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 delay REM latency in already fit individuals. We are able to see the effects of actual increase in sleep changes when the individuals performs exercise longer than 1 hour a day. However, further research is required to know, if performing exercise for longer period will bring an improvement in sleep quality in individuals[5].

Exercise and Fitness

We can say that physical fitness are achieved when we consume appropriate nutrition, perform moderate to vigorous exercises and have an adequate rest. If an individual is not able to fulfill these criteria, he/she is falling sick, having low energy level, suffering from disease and hopelessness we consider them as unfit. There are a few researches suggest; vigorous level of exercise can help in improving sleep quality. However, there is 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 suggest, there is no role of fitness with regards to exercise & sleep and such findings indicates that exercise encourages sleep in wide range of population[5].

Exposure to Outdoor light

Appropriately, timely exposure to bright light can enhance the sleep quality among 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[5].

Anti-Depressant effects

Sleep disturbance is one of the most common characteristic features among individuals suffering from anxiety. According to evidences, the findings are able to prove that anxiolytic therapeutic therapies are effective in treating the patients suffering from sleeplessness.  Moreover, speaking about exercise, researches are also able to show that exercises are effective in reducing anxiety by providing psychophysiological treatment effect. It promotes better control between the mind and body, helps in improving the conditions and symptoms of patients suffering from anxiety. Possibly, exercise could promote better sleep by reducing the anxiety symptoms. Apart from that, evidences also suggest that individuals suffering from sleeplessness are more prone to developing depression. Thus, findings support that chronic exercise are able to encourage sleep by promoting anti-depressant effects and reduces depression. There is observable reduction in REM sleep due to acute exercise and such reductions we are able to find in anti-depressant treatments[5].

Conclusion

Exercises have a therapeutic effect on individuals suffering from sleep disorders and it is beneficial in promoting sleep. It reduces worry, anxiety and depressive symptoms among patients. However, further research is required for understanding the impact of exercise on sleep more clearly. In addition, Exercise actually reduces the death and disease rate, and it should be a part of daily regimen. Health care providers can recommend exercise as a treatment plan in order to boost the health and sleep of people and maintain physical well-being of a person.

Resource

The brain-changing benefits of exercise[12]

References

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