Physical exercise and its effects on health and sleep

Physical activity: mechanisms for health and sleep remain to be elucidated, but most studies consider the overall effect to be positive. Credit: Pxfuel

Unless I am mistaken, even sedentary people do not deny the benefits of practicing physical exercises for health promotion. Sleep specialists, on the other hand, add to the list of positive effects of exercises the improvement of the quality of the sleep. However, they warn that the practice is avoided close to bedtime, which would make it difficult to fall asleep. On the other hand, the mechanisms that explain this relationship between exercise and sleep are not fully understood.

In 2017, a group of researchers from the University of California carried out a systematic review based on a bibliographic survey of the previous four years exactly on the exercise-sleep relationship. Objective or subjective measures of sleep and an exercise intervention according to the guidelines recommended by the American College of Sports Medicine were the criteria that included 34 studies in the review. Among these, 29 studies concluded that exercise improved the quality or duration of sleep. However, four found no difference and one reported a negative impact of exercise on sleep. Factors such as age, health status, and type or intensity of exercise may explain the variation observed between the results of the reviewed studies.

Exercise practice was especially positive among older people in order to promote an increase in the efficiency and duration of sleep, regardless of the mode and intensity of the activity, especially in populations with diseases.

Substantial positive effects

The authors conclude that sleep and exercise have substantial positive effects on each other, but they emphasize that the mechanisms behind these observations must be elucidated.

The increase in body temperature during exercise is, without a doubt, a factor that is known to change sleep latency, making it difficult to fall asleep, when the exercises are performed immediately before sleep onset. Aerobic exercises also release endorphins, increasing alertness, which reinforces the recommendation to avoid physical exercise before sleep. On the other hand, physical exercises practiced throughout the day promote alertness and reduce sleepiness, in order to reduce sleep latency at night. Regular moderate exercise practice, during leisure time, contributes to the reduction of body weight and musculoskeletal pain, in addition to improving respiratory capacity. Together, these factors reduce the chance of developing illnesses, including sleep disturbances.

Thus, although all mechanisms involved in improving sleep quality resulting from exercise practice have not been elucidated, there is already a consistent basis of evidence to recommend exercise practice as a measure of promoting good quality sleep. There is, for example, enough evidence for the American National Sleep Foundation to recognize that sleep and exercise have a bidirectional relationship. In other words, optimizing exercise can potentially improve sleep quality, and getting adequate sleep can promote daytime physical activity.

the best time

It still remains to know what is the best time to practice physical activity. The biological timing system regulates the body’s processes at a rate of approximately 24 hours. This system influences many aspects of performance, ranging from physiological effects to motivational, perceptual and cognitive factors.

From a biological point of view, it makes sense to assume that physical activity performance in the late afternoon is better than in the morning. In a study of the time of day of physical activity (morning versus night) and the effects of consuming a high-fat diet on glycemic control, Australian researchers followed overweight/obese men who consumed a diet containing 65% of the energy from fat per day. 11 consecutive days. After five days on the diet, participants were randomly allocated to exercise in the morning (6:30 am), exercise in the late afternoon (6:30 am) or no exercise for the next five days. Twenty-four participants completed the study and were included in the analyzes (eight per group).

Physical activity practice had a smaller impact than high-fat diet on changes in circulating metabolites, and only late afternoon exercise was able to partially reverse some of the high-fat diet-induced changes in metabolomic profiles. Improvements in cardiorespiratory fitness were similar regardless of the time of day of physical activity. However, improvements in glycemic control and partial reversal of high-fat diet-induced changes in metabolic profiles were seen only when participants exercised in the late afternoon.

Biological characteristics

In another study, researchers from the University of Groningen in the Netherlands investigated the effect of time of day on the assessment of physical performance of Olympic athletes. The researchers noted that the worst performance was in the early morning, around 5:00 am, while the best performance was observed in the late afternoon, around 5:00 pm.

Thus, although common sense suggests that the best time of day to practice physical activity is early in the morning, studies suggest that this statement is not valid in a general way. First, one must take into account the person’s biological characteristics, which lead to variation in performance throughout the day. An extreme afternoon should express his best performance in the early evening, while an extreme morning one much earlier. Another consideration concerns the expected performance of physical training. It’s obvious that athletes prefer times when their performance is best, but if the goal of training is to promote health, performance is likely not as important.

Light and moderate exercises can be practiced in the morning when there is no concern with performance and as long as they are performed only by people who feel good exercising at that time. Glycemic control, on the other hand, seems to be more efficient when training is performed in the late afternoon. Finally, the concern with increasing the time to fall asleep due to the practice of physical activity close to the time when sleep starts does not prevent it from being performed in the late afternoon, as long as it is performed a few hours before sleep onset.

* Claudia RC Moreno is a professor at the Faculty of Public Health (FSP) at USP.

See too

+ Ana Maria Braga’s marriage comes to an end after her husband mistreats employees, says columnist

+ Learn about the effectiveness of each vaccine against Covid-19

+ See photos of Karoline Lima, Neymar’s new affair

+ Lázaro Barbosa manages to flee the police again after shooting

+ Gracyanne Barbosa dance pole dance with new look

+ US agency warns: never wash raw chicken meat

+ After suing daughter-in-law, Medina’s mother accuses her of having destroyed her house; see pictures

+ Yasmin Brunet breaks the silence

+ Easy-to-make chocolate fondue with fruit

+ Shark is captured in MA with the remains of youngsters missing in the stomach