Gender differences in nighttime sleep and daytime napping as predictors of mortality in older adults: The Rancho Bernardo Study

Abstract Objective Many studies suggest optimal sleep duration for survival is 7–8 h/night. We report the gender-specific independent association of all-cause mortality with nighttime sleep and daytime nap duration in older adults who were followed for up to 19 years. Methods Between 1984 and 1987, 2001 community-dwelling, mostly retired, adults (1112 women), age 60–96 years, answered questions about health, mood, medications, life-style, daytime napping, and nighttime sleep duration. Vital status was confirmed for 96% through July 2001. Results At baseline, men reported significantly longer nighttime sleep and daytime napping than women. In both men and women, nighttime sleep