Exercise and sleep in community-dwelling older adults: evidence for a reciprocal relationship.

Exercise behaviour and sleep are both important health indicators that demonstrate significant decreases with age, and remain modifiable well into later life. The current investigation examined both the chronic and acute relationships between exercise behaviour and self-reported sleep in older adults through a secondary analysis of a clinical trial of a lifestyle intervention. Seventy-nine community-dwelling, initially sedentary, older adults (mean age = 63.58 years, SD = 8.66 years) completed daily home-based assessments of exercise behaviour and sleep using daily diary methodology. Assessments were collected weekly and continued for 18 consecutive weeks. Multilevel models revealed a small positive chronic (between-person mean-level) association between exercise and wake time after sleep onset, and a small positive acute (within-person, day-to-day) association between exercise and general sleep quality rating. The within-person exercise and general sleep quality rating relationship was found to be reciprocal (i.e. sleep quality also predicted subsequent exercise behaviour). As such, it appears exercise and sleep are dynamically related in older adults. Efforts to intervene on either sleep or exercise in late-life would be wise to take the other into account. Light exposure, temperature regulation and mood may be potential mechanisms of action through which exercise can impact sleep in older adults.