Sleep is considered to be the most potent health-enhancing weapon known to humankind, affecting our weight, blood pressure, and emotional well-being. Poor sleep has been linked to numerous health issues, and thus improving sleep is crucial for overall well-being.
Fortunately, a new study, published today in the European Journal of Preventive Cardiology, of over 90,000 adults has found that physical activity can help counteract some of the negative effects of unhealthy sleep duration on longevity.
The findings of the study revealed “that increased physical activity levels weakened the mortality risks associated with short or long sleep duration,” according to study author Dr. Jihui Zhang.
While it has long been established that both regular exercise and healthy sleep patterns are key contributors to a longer life, previous research relied on self-reported physical activity and sleep data which may be subject to bias. In contrast, this study used an accelerometer wristband to objectively record movement and provide more reliable estimates of both activity and sleep duration.
The study, which is the first to examine the joint effects of physical activity and sleep duration on mortality risk using accelerometry, included 92,221 adults between the ages of 40 and 73 who wore the wristband for one week between 2013 and 2015 as part of the UK Biobank cohort.
During the study, participants’ sleep duration per night was classified as short (less than six hours), normal (six to eight hours), or long (more than eight hours), while total volume of physical activity was divided into low, intermediate, and high tertiles. Participants were also classified as meeting or not meeting World Health Organization (WHO) guidelines for moderate to vigorous physical activity. Mortality data were collected from death registries, with the primary outcome being all-cause death and secondary endpoints being death due to cardiovascular disease and death due to cancer.
The participants’ average age was 62 years, and 56% of them were women. Over a median follow-up period of seven years, 3,080 participants passed away, with 1,074 deaths attributed to cardiovascular disease and 1,871 deaths attributed to cancer.
The impact of physical activity on the relationship between sleep and mortality was investigated by the researchers. Two aspects were examined: the volume of activity and moderate to vigorous physical activity. To account for potential confounding factors, such as age, sex, ethnicity, deprivation, education level, season of sleep measurement, body mass index, diet, smoking, alcohol intake, and shift work, the analyses were adjusted.
In individuals with low levels of physical activity, both short and long sleep durations were linked to 16% and 37% higher risks of all-cause mortality, respectively. However, for those with intermediate levels of physical activity, only short sleep was associated with a 41% increased risk of all-cause mortality. In individuals with high levels of physical activity, there was no association between sleep duration and the risk of death.
Regarding cardiovascular death, short sleepers with low levels of physical activity had a 69% higher risk of mortality, which disappeared when physical activity increased to moderate or high levels. For cancer-related mortality, long sleepers with low levels of physical activity had a 21% higher risk, which disappeared with moderate or high levels of physical activity.
The results for moderate to vigorous physical activity were comparable. In individuals who did not meet the World Health Organization (WHO) recommendations, both short and long sleep durations were associated with 31% and 20% increased risks of all-cause mortality, respectively. However, these risks were no longer observed in those who met the WHO recommendations.
For cardiovascular mortality, short sleepers who did not meet the WHO recommendations for physical activity intensity had a 52% higher risk of mortality, which disappeared in those who met the recommendations. For cancer-related mortality, long sleepers who did not meet the WHO recommendations had a 21% increased risk, which was no longer observed in those who followed the WHO guidelines.
According to Dr. Zhang, the results indicate that promoting both physical activity and adequate sleep duration could be more effective in preventing or delaying premature death in middle-aged and older adults than focusing solely on one behavior.
While it would be ideal for individuals to maintain healthy levels of both physical activity and sleep, the study suggests that getting enough exercise could partly counteract the negative effects of insufficient sleep.
Source: 10.1093/eurjpc/zwad060
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