Sleep duration and health: results of the Moscow pilot study on physiological mechanisms of stress-related hazard
Maria A. Shkolnikova, Max Planck Institute for Demographic Research
Blake Aber, Columbia University
Maxine Weinstein, Georgetown University
A sample of 201 individuals aged 67 to 86 from the Moscow Lipid Research Clinics epidemiological cohorts of 1975 and 1983 was interviewed and medically tested in 2002-03. In many studies duration of sleep information is based on self-reporting. It leads to significant biases. In the present study the sleep duration was measured objectively from the 24-hour heart rate (Holter) monitoring. Comparison with reported sleep shows significant differences, which result in substantial underestimation of the impact of sleep on health outcomes. In general, longer sleep duration is correlated with mobility limitations, lower grip strength, depressed cognitive function, higher perceived stress, and higher mortality risk score. Episodes of daytime sleep are also correlated with mobility limitation and lower grip strength.