Exercise can combat the side effects of poor sleep

Not getting enough sleep can lead to a variety of health consequences, but a new study has found that high-intensity workouts may combat some of these negative side effects.

Good sleep and adequate physical activity help prevent more than 80% of cardiovascular events, including heart attacks, abnormal heart rhythms, and coronary heart disease. But getting into lasting habits in these two areas can be difficult for many people. While exercise may be more within the control of individuals – you can choose to go for a run and then do it – sleep may be sought after but more complicated to pin down.

The good news is that maintaining these exercise habits while striving to improve sleep still offers positive benefits.

According to one of the study’s co-authors, Jihui Zhang, PhD, director of the Center for Sleep and Circadian Medicine at the Affiliated Brain Hospital of Guangzhou Medical University, China, this may be due to the effect of exercise on inflammation, metabolism, and the sympathetic nervous system, all of which are closely linked to heart health.

“Therefore, to some extent people should sacrifice rest for exercise if they have to choose one,” he said.

Getty Images / Luis Alvarez

To understand the role exercise plays in combating the side effects of poor sleep, the researchers used data collected from over 92,000 adults in the UK between 2013 and 2015. Their ages ranged from 40 to 73 years old and 56% were women. For a week, they wore a bracelet that measured how much they exercised and slept.

They divided nighttime sleep into three categories: short (six hours or less), normal (six to eight hours) and long (more than eight hours). Based on the guidelines of the World Health Organization (WHO), they divided the amount of physical activity a person has into low, intermediate and high. The research team also tracked exercise intensity and whether or not it was considered “moderate to vigorous” according to WHO guidelines.

The study used death records to determine that after a median of about seven years after the data was collected, just over 3,000 participants died, about 1,100 from cardiovascular disease and about 1,900 from cancer.

Those who slept too much or too little and did not exercise enough – less than the recommended 150 minutes per week – were more likely to die from any cause, including cancer and heart disease.

In those who didn’t get enough sleep, exercising more than the minimum recommended amount seemed to compensate for the sleep loss. People who exercised more than 150 minutes per week had no increased risk of dying, even if they slept less than six hours each night.

This was not the case for people who exercised in between. In these people, not getting enough sleep increased their likelihood of death from all causes by about 40%.

The new research was observational, meaning it cannot confirm that exercise can lessen some of the effects of sleep loss, but Dr. Zhang and his team point to exercise’s ability to fight inflammation. , metabolic dysregulation and sympathetic nervous system activity.

According to a previous study, muscle contractions during exercise release exerkines, molecules that can reduce inflammation associated with chronic diseases, including heart disease and diabetes.

Inflammation of the cardiovascular system can affect blood flow to the heart and the tissues surrounding the organ. This can lead to serious health problems, including arrhythmia (irregular heartbeat) and heart failure, which means your heart can’t pump enough oxygen-rich blood to meet your body’s needs, and the narrowing of the arteries.

Exercise works to counter inflammation; it also regulates cholesterol, excess fat, and high blood sugar, all of which contribute to heart disease. It also stimulates the sympathetic nervous system, which impacts heart rate and the heart’s ability to pump with the right force.

Although the new study did not specifically investigate whether too much exercise can have health consequences related to heart disease, cancer and overall mortality, previous research has suggested that too much exercise and not enough rest can increase harmful inflammation.

A 2019 study found that an adequate amount of exercise reduces inflammation, but too much can cause working muscles to trigger immune cells to release inflammatory mediators – a host of blood cells, proteins and other mediators that use inflammation to fight off intruders such as bacteria and viruses. Research has found that intense and long exercise can lead to higher levels of inflammatory mediators and therefore chronic inflammation.

According to Bo-Huei Huang, PhD, an epidemiologist and biostatistician at the University of Technology Sydney in Australia, who studies the intersection of fitness and sleep, the amount and intensity of exercise each person needs will depend on a number of factors, including age, whether someone is pregnant or has a chronic illness or disability. The same goes for sleep: some people need more than others.

The findings also may not transfer to younger people, who generally need more sleep than older adults, noted Tamanna Singh, MD, co-director of the Sports Cardiology Center at the Cleveland Clinic.

“All of this data is still so new, I think there’s a lot more than what we already know,” she explained.

Studies like this, which compare two aspects of health that are both important, should inspire people to become more intentional about their habits.

“If you’re not already moving, now is a good time to add intentional movement to your daily list of things that are important to you,” Dr. Singh suggested, acknowledging that different factors, including work, can make easier for some. that others.

Huang stressed that the importance of sleep cannot be overlooked. In 2022, the American Heart Association (AHA) added sleep to its list of eight crucial lifestyle factors for heart health, noting that adults should aim for 7-9 hours per night.

If exercise replaces restful sedentary behaviors that aren’t sleep, such as sitting on the couch while watching TV, the outcome will almost certainly be positive for a person’s health, Dr. Huang reiterated. But not getting enough sleep and expecting to erase the effects with exercise probably won’t be good for your long-term health.

“When we think about overall cardiovascular fitness, it’s not that one thing is more important than the other,” Dr. Singh agreed. “It’s all about balance.”

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