Study Shows a Decline in Physical Activity Increases the Risk for Sleep Disorders

Having trouble falling asleep? Finding it difficult to perform daily tasks like walking up 10 stairs, stooping, crouching or kneeling? Well, your sleep difficulty and physical functioning may be related.

Dr. Jeffrey Herrick of the Department of Rehabilitation Science and his team of faculty and doctoral student researchers recently completed a 10-year analysis that found that limitations in physical function (PF) can increase your risk for developing a sleep disorder (SD). The effect was especially apparent in adult males.

Herrick explains, “We undertook this study to gain a better understanding of the relationship between diagnosed sleep disorders and the effects on performing daily functional tasks. From our work it is clear that adults should consider their sleep as a factor that may be affecting their daily physical functioning and impacting their quality of life and overall health.”

The study used data from the National Health and Nutrition Examination Survey (NHANES) from year 2005 to 2014. NHANES covers a nationally representative sample of the resident civilian non-institutionalized U.S. population. From that group, individuals were selected who had completed both the PF questionnaire and the SD questionnaire, which resulted in a sample for this study of 9,618 adults between ages 20 and 83.

The research team assessed PF by self-reported difficulty in performing a selection of 10 activities of daily living. SD was determined by a previously recorded physician diagnosis of a SD to include insomnia, obstructive sleep apnea, and/or restless leg syndrome. They found that adults with a self-reported PF limitation have 41% higher odds of having a diagnosed SD. Females were 27% less likely to have a SD than males, however, it is suspected that SDs in women are under-diagnosed. Regardless, the relationship between sleep quality and the ability to perform daily living tasks is quite clear.

Since SDs are commonly associated with other major health problems, the study also looked at the effect of comorbid conditions such as cardiovascular and pulmonary disease, metabolic conditions including obesity and diabetes, musculoskeletal conditions like arthritis, all forms of cancer, and cognitive disorders such as depression and anxiety. Participants having cognitive disorders and cardiovascular and pulmonary disease as secondary conditions have 145% and 28% higher odds of having a diagnosed SD. However, as Herrick clarifies, “This relationship is complex and could benefit from additional study to understand more specifically the relationship between the mechanisms of comorbid conditions and sleep.”

Herrick explains that there are some limitations to the study. “Unfortunately the NHANES study did not allow us to determine which came first—the decline in PF or the SDs—so we were not able to show causation. Additionally, SD were grouped and not categorized in the data set, so we weren’t able to determine the individual relationships between insomnia, obstructive sleep apnea, and restless leg syndrome and declines in PF.”

Nevertheless, Herrick and colleagues can see this present study as a stepping stone for future longitudinal and mechanistic studies exploring the influence of rehabilitation interventions on physical functioning and SDs.

With daytime sleepiness or difficulty in falling asleep reported by more than a third of all U.S. adults, the research group strongly recommends that adults engage in daily moderate to vigorous physical activity which has the potential to enhance physical functioning and may prevent or delay the onset of sleep disorders.