Regular exercise associated with recommended duration of sleep, reduced insomnia symptoms

Key takeaways:

• Regular exercise reduced the risk for insomnia symptoms and longer and shorter sleep durations.
• The findings also show the importance of consistently exercising over time, researchers said.

Exercise just two to three times a week reduced the risk for multiple insomnia symptoms and extreme sleep durations both short and long, a study published in BMJ Open showed.

“Regular exercise is associated with better health and several studies suggest that physical activity is beneficial to sleep and may improve symptoms of chronic insomnia,” Erla Björnsdóttir, PhD, a postdoctoral researcher from the University of Reykjavík, in Iceland, and colleagues wrote. “It is, however, unclear how significant these benefits are and which factors may have a moderating effect on them.”

In the study, the researchers evaluated the frequency, intensity and duration of physical activity, symptoms of insomnia and sleep duration among participants (n = 4,339) aged 37 to 67 years from the European Community Respiratory Health Survey III cohort study.

Participants (48% men) answered questions on physical activity levels at baseline, and questions on sleep duration and insomnia 10 years later.

Björnsdóttir and colleagues categorized those who exercised two to three times a week, for 1 hour or more a week, as persistently active.

From baseline to follow-up, 36.9% of participants were persistently nonactive, 24.9% were persistently active, 20.3% became inactive and 17.9% became active.

Participants who were persistently active at follow-up were less likely to report:

• two or three insomnia symptoms (OR = 0.6; 95% CI, 0.45-0.78);
• a sleep duration of 6 hours or less a night (OR = 0.71; 95% CI 0.59-0.85); and
• a sleep duration of 9 hours or more a night (OR = 0.53; 95% CI 0.33-0.84).

Associations remained significant even after Björnsdóttir and colleagues adjusted for age, sex, BMI and smoking history.

Those who were persistently active were more often men, younger, less likely to be smokers and had a slightly lower BMI.

Persistently active participants (OR = 1.55; 95% CI, 1.29-1.87) and those who became active (OR = 1.21; 95% CI, 1-1.47) were also more likely to be normal sleepers vs. those who were persistently inactive.

The study “shows the importance of consistency in exercising over time, because the association was lost for initially active subjects who became inactive,” the researchers explained.

There were several limitations to the research, however. For example, physical activity was measured with just a questionnaire, and residual confounders that could impact both sleep and exercise — like mental health — were not assessed.

Additionally, “we did not explore cognitive function in the current study but it would be interesting for future studies to explore further how cognitive function is affected by the association of physical activity and sleep,” Björnsdóttir and colleagues wrote.

References:

• Björnsdóttir E, et al. BMJ Open. 2024;doi:10.1136/bmjopen-2022-067197.
• Consistently exercising 2-3 times a week over the long term linked to lower current insomnia risk. https://www.eurekalert.org/news-releases/1038722. Published March 26, 2024. Accessed March 27, 2024.