Sleep Duration and Disturbances Were Associated With Testosterone Level, Muscle Mass, and Muscle Strength--A Cross-Sectional Study in 1274 Older Men

• Published in: Journal of the American Medical Directors Association Vol. 16; no. 7; p. 630.e1
• Main Authors: Auyeung, Tung Wai, Kwok, Timothy, Leung, Jason, Lee, Jenny Shun Wah, Ohlsson, Claes, Vandenput, Liesbeth, Wing, Yun Kwok, Woo, Jean
• Format: Journal Article
• Language: English
• Published: United States 01.07.2015
• Subjects: Aged; Aging; Cross-Sectional Studies; Hong Kong; Humans; Male; Muscle Strength - physiology; Muscle, Skeletal - physiology; Sleep; Sleep Wake Disorders - etiology; Surveys and Questionnaires; Testosterone - blood; Hong Kong; sleep; Testosterone; old age; muscle
• ISSN: 1538-9375
• DOI: 10.1016/j.jamda.2015.04.006

Testosterone level follows a circadian rhythm. However, whether sleep duration and disturbances can affect testosterone level, muscle mass, and strength remains unknown. To examine the relationship of sleep duration and disturbances to testosterone level, muscle mass, muscle strength, and walking speed. We recruited 1274 community-dwelling men older than 65 years of age. Their early morning testosterone level was assayed by mass spectrometry. A sleep questionnaire was administered to enquire about their reported sleep duration, prolonged sleep latency (>0.5 hour), and subjective insomnia complaint. Muscle mass was measured by dual-energy x-ray absorptiometry. Testosterone level, muscle mass, handgrip strength, and walking speed were tested against sleep duration and disturbances. Testosterone increased with increasing sleep duration up to 9.9 hours, after which it decreased, giving rise to an inverted U-shaped relationship (P for quadratic trend <.05). A similar inverted U-shaped relationship occurred between sleep duration and muscle mass and function. Earlier go-to-bed time, despite being associated with a higher testosterone level (P < .05), was associated with weaker grip strength (P < .05). Earlier wake-up time was associated with higher muscle mass (P < .05) but neither grip strength nor walking speed. Neither prolonged sleep latency nor insomnia was associated with testosterone levels. However, prolonged sleep latency was associated with lower muscle mass (P < .05), weaker grip strength (P < .05), and slower walking speed (P < .001). Insomnia, on the other hand was associated with weaker grip strength (P < .05) and slower walking speed (P < .001) but not muscle mass. Sleep duration and disturbances can affect testosterone level, muscle mass, and its function. Whether optimization of sleep can ameliorate age-associated decline in sex hormone and muscle performance warrants further studies.