Sleep efficiency and the metabolic risk score in very active older women and men.

Study objectives: Sleep disruption is a risk factor for obesity, diabetes, and cardiovascular disease in older adults. How physical activity (PA) interacts with the negative cardiometabolic effects of poor sleep is not known. We objectively measured sleep efficiency (SE) in very active older adults and examined the association between SE and a continuous Metabolic Syndrome Risk Score (cMSy).

Methods: Very active older adults (age ≥65 years) from a Master's Ski Team (Whistler, Canada) were recruited. Each participants wore an activity monitor (SenseWear Pro) continuously for 7 days to provide measures of both daily energy expenditure (metabolic equivalents, METs) and SE. All components of the metabolic syndrome were measured and a principal component analysis was used to compute a continuous metabolic risk score (cMSy, sum of eigenvalues ≥1.0).

Results: A total of 54 participants (mean age 71.4 years, SD 4.4 years, and 24 men and 30 women) were recruited and had very high PA levels (>2.5 h per day of exercise). Initially, there was no significant association between SE and cMSy (p = 0.222). When stratified by biological sex, only men showed a significant negative association between SE and cMSy (Standardized β = -0.364 ± 0.159, p = 0.032).

Conclusions: Only older men show a significant negative association between poor SE and increased cardiometabolic risk, despite high levels of PA.