Objective sleep duration and health in elderly Russians

Abstract

Objectives - We examine the relationship between sleep duration and health in the high mortality context of Russia. Methods - Night and daytime sleep durations are based on self-reports and 24-hour heart rate trends (Holter monitoring). The sample of 201 individuals (Holter data for 185) is drawn from the Moscow Lipid Research Clinics cohort, followed up since 1975-77. Field-work occurred in 2002-03. Results - Although objective and reported mean sleep are similar, there are significant intra-individual differences. Significant associations are found between objective sleep and health: longer sleep corresponds to lower grip strength, poorer self-rated health and immediate recall, and higher mortality risk score. No significant relationships are found for subjective sleep. Conclusions - We provide the first evidence of an association between long sleep and worse health outcomes among elderly Russians. Predictive power increases if objective sleep measures are used, a consideration which is especially important in small studies.