Engaging in or exceeding the weekly recommended amount of physical activity (PA) may offset serious health risks associated with poor sleep quality, including death, new research suggests.
Investigators analyzed data on close to 400,000 middle-aged adults and found that over an 11-year period, those with poor sleep together with low levels of PA had 57% higher risk for all-cause mortality, a 67% higher risk for death from cardiovascular disease (CVD), a 45% higher risk for death from any type of cancer, and a 91% higher risk for death from lung cancer in comparison with their counterparts with good sleep and high PA levels.
“Our study found that PA amplified the premature mortality risks of poor sleep in a synergistic way, and conversely, meeting PA recommendations countered most of the risks of poor sleep,” study investigator Emmanuel Stamatakis, PhD, professor, Charles Perkins Center, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia, told Medscape Medical News.
The study was published online June 29 in the British Journal of Sports Medicine.
Combined Effects?
Physical activity and sleep are both critical for good health, but at a global level, many individuals don’t get the necessary levels of either, which causes huge disease burden and compromised quality of life, Stamatakis said.
PA and sleep each independently affect health outcomes. It is also possible that they “influence health conditions through related pathways.” However, “we know very little about the combined effects of these two key aspects of our lifestyle,” the authors note.
To investigate possible “combined effects,” the researchers used data from participants in the UK Biobank, a prospective cohort of over 500,000 adults who were recruited between 2006 and 2010, as well as mortality information from national datasets.
Participants’ normal weekly PA levels were measured in metabolic equivalent of task minutes (MET-min) , which are roughly equivalent to the amount of energy expended per minute of physical activity, according to Stamatakis.
PA was categorized as low (0 to <600 MET-min/wk), medium (600 to <1200 MET-min/wk), or high (≥1200 MET-min/wk). The researchers also created a “no moderate-to-vigorous PA” (MVPA) category.
The World Health Organization recommends 150 minutes of moderate or 75 minutes of vigorous PA weekly, Stamatakis noted.
The researchers created a “novel healthy sleep score” that was based of five healthy sleep characteristics: morning chronotype; adequate sleep duration (7 – 8 hr/d); not usually experiencing insomnia; not snoring; and no frequent daytime sleepiness.
Participants were given a sleep score of 1 to 5, with ≥4 indicating “healthy sleep, 2 or 3 indicating “intermediate sleep,” and ≤1 indicating “poor sleep.”
Covariates included age, sex, body mass index (BMI), socioeconomic status, fruit and vegetable intake, sedentary behavior, mental health status, cigarette smoking, employment status, alcohol consumption, and PA or sleep score.
Participants with a baseline history of total CVD or cancer were excluded. The researchers also excluded patients who died from COVID-19.
Participants were followed for a mean of 11.1 years to May 2020 or death (all-cause, total CVD, coronary heart disease [CHD], hemorrhagic stroke, ischemic stroke, total cancer, and lung cancer).
Synergistic Effects
Of those who met inclusion criteria (n = 380,055; mean [SD] age, 55.9 [8.1] years; 45% men; mean BMI, 26.9 [4.1]), 3% had poor sleep, 42% had intermediate sleep, and 56% had healthy sleep.
Over half (59%) had high levels of PA; 16% had no MVPA; 10% had low PA; and 15% had medium PA.
“Participants who were younger, women, thinner, faced less socioeconomic deprivation, had higher vegetable and fruit intakes, sat less, had no mental health issues, never smoked, were employed in non-shift work, drank less alcohol and had more PA, tended to have healthier sleep scores,” the authors report.
After adjusting for confounders and PA levels, poor and intermediate sleep were associated with higher mortality risks, compared to healthy sleep:
| Mortality | Poor sleep HR (95% CI) | Intermediate sleep HR (95% CI) |
|---|---|---|
| All-cause | 1.23 (1.13 – 1.34) | 1.05 (1.02 – 1.09) |
| Total CVD | 1.39 (1.19 – 1.62) | 1.09 (1.03 – 1.17) |
Poor sleep was associated with ischemic stroke (HR, 1.94 [1.29 – 2.94]); intermediate sleep was associated with CHD (HR, 1.16 [1.06 – 1.27]).
Compared with participants who had a high level of PA, those with lower PA levels were at incrementally higher risk for all-cause mortality after adjusting for confounders.
| Medium PA | Low PA | No MVPA |
|---|---|---|
| 1.05 (1.01 – 1.10) | 1.08 (1.02 – 1.14) | 1.25 (1.20 – 1.31) |
Participants with no MVPA were also at higher risk for all the other conditions except for hemorrhagic stroke:
| Total CVD | 1.31 (1.21 – 1.42) |
| Total cancer | 1.16 (1.10 – 1.23) |
| CHD | 1.35 (1.21 – 1.52) |
| Ischemic stroke | 1.38 (1.07 – 1.77) |
| Lung cancer | 1.35 (1.19 – 1.53) |
Participants with the poorest sleep quality who also exercised the least were at the greatest risk for adverse outcomes (other than hemorrhagic stroke), compared to those with high PA plus good sleep:
| Medium PA | Low PA | No MVPA |
|---|---|---|
| 1.05 (1.01 – 1.10) | 1.08 (1.02 – 1.14) | 1.25 (1.20 – 1.31) |
“The detrimental associations of poor sleep with all-cause and cause-specific mortality risks are exacerbated by low PA, suggesting likely synergistic effects,” the authors write.
“By ‘synergistic effects,’ we mean that physical inactivity amplified the health risks of poor sleep in a way that the combined mortality risk from physical inactivity and poor sleep was larger than the sum of the independent risks of por sleep alone plus physical inactivity alone,” said Stamatakis explained.
“Win-Win”
Commenting for Medscape Medical News, Nitun Verma, MD, a spokesperson of the American Academy of Sleep Medicine, said that although the study is associational and did not evaluate causality, it nevertheless “adds to the body of research linking healthy sleep and physical activity with improved health.”
Verma, a sleep physician at AC Wellness, Cupertino, California, who was not involved with the study, said it “reinforces the importance for clinicians to consider both the sleep health and physical activity of all patients in primary care.”
Stamatakis agreed.
“By adding a physical activity prescription to a sleep disorder treatment plan, clinicians will assist patients to enjoy the multitude of direct health benefits of an active lifestyle, improve their sleep patterns and, as our new study shows, may even mitigate some of the health risks that come from poor sleep. Investing in physical activity is a win-win all around investment for clinicians and public alike,” he said.
Stamatakis’ work was funded by a fellowship from the National Health and Medical Research Council. His coauthors and Verma have disclosed no relevant financial relationships.
Br J Sports Med. Published online June 29, 2021. Abstract
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