Exercise counteracts negative effects of sleep deprivation

New research published in the European Journal of Preventive Cardiology indicates that physical activity may counteract some of the negative effects associated with both too little and too much sleep on life expectancy. 

The study, conducted by scientists at the Affiliated Brain Hospital of Guangzhou Medical University in China, involved more than 90,000 adults and employed accelerometer technology to provide more reliable and objective measurements of physical activity and sleep duration.

Lead author Dr. Jihui Zhang explained the study’s findings, stating that “increased physical activity levels weakened the mortality risks associated with short or long sleep duration.” This suggests that even though both adequate sleep and exercise are vital for longevity, engaging in physical activity can help mitigate the potential health consequences of poor sleep habits.

While the relationship between sleep, exercise, and health has long been studied, the specific interaction between physical activity and sleep duration had not yet been fully understood. 

One key limitation of prior research was the reliance on self-reported data for physical activity and sleep, which can be subjective and prone to inaccuracies. In order to address this issue, the current study utilized accelerometer wristbands to measure participants’ movement, offering a more reliable and objective assessment of activity levels and sleep duration.

This groundbreaking research is the first to examine the combined effects of physical activity and sleep duration on mortality risk using accelerometry. The study included a diverse group of 92,221 adults aged 40 to 73 from the UK Biobank cohort, who wore the accelerometer wristbands for a week between 2013 and 2015. 

Sleep duration per night was categorized as short (less than six hours), normal (six to eight hours), or long (more than eight hours), and physical activity was divided into tertiles (low, intermediate, high). The researchers also classified moderate to vigorous physical activity as meeting or not meeting the World Health Organization (WHO) guidelines.

Over a median follow-up period of seven years, 3,080 of the participants died – 1,074 from cardiovascular disease and 1,871 from cancer. The study’s primary outcome was all-cause death, with secondary endpoints being death due to cardiovascular disease and death due to cancer.

The analysis reveals that engaging in physical activity can help reduce the mortality risks associated with both short and long sleep duration. The researchers aimed to understand how physical activity influenced the impact of sleep on mortality by examining the volume of activity and moderate to vigorous physical activity levels. 

The study accounted for factors that could potentially influence the relationship, such as age, sex, ethnicity, deprivation, education level, season of sleep measurement, body mass index, diet, smoking, alcohol intake, and shift work.

The experts found that among participants with low amounts of physical activity, short and long sleep were associated with a 16 and 37 percent increased risk of all-cause death, respectively. However, in those with intermediate amounts of exercise, only short sleep duration was detrimental, raising the likelihood of all-cause death by 41 percent. 

Among participants with a high amount of exercise, sleep duration was not linked to an increased risk of death. When it came to cardiovascular death, short sleepers with a low volume of exercise faced a 69 percent elevated risk, which disappeared when exercise increased to moderate or high volumes. For cancer death, long sleepers with low amounts of exercise had a 21 percent increased risk, which disappeared with moderate or high volumes of exercise.

Similar results were observed for moderate to vigorous physical activity. In participants not meeting the World Health Organization (WHO) recommendations, short and long sleep were associated with 31 and 20 percent increased risks of all-cause death, respectively. 

These risks disappeared in those who met the WHO recommendations. For cardiovascular death, short sleepers who did not meet the exercise intensity advice faced a 52 percent elevated risk, which disappeared in those achieving the recommendations. For cancer death, long sleepers not meeting the advice had a 21 percent increased risk, which disappeared in those following the WHO guidance.

“Our findings suggest that health promotion efforts targeting both physical activity and sleep duration may be more effective in preventing or delaying premature death in middle-aged and older adults than focusing on one behavior alone,” said Dr. Zhang. He emphasized the importance of achieving healthy amounts of both sleep and physical activity, but acknowledged that the study indicates that “getting sufficient exercise may partially offset the detrimental impact of missing a good night’s sleep.”

The results of this research underscore the importance of maintaining a healthy lifestyle that includes both sufficient sleep and regular physical activity. Further, they highlight the potential for physical activity to help mitigate some of the negative effects of inadequate or excessive sleep on life expectancy. As our understanding of the complex interplay between sleep and exercise continues to grow, these findings offer valuable insights for individuals looking to optimize their health and well-being.

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