Overnight Temperature Regulation Improves Circadian Rhythm and Cardiovascular Recovery in Postmenopausal Women and Age-Matched Men

Abstract Sleep quality declines during menopause, yet the associated changes in body temperature and circadian rhythm during sleep remain poorly understood. In 90 postmenopausal women and age-matched men (1408 nights; mean ± SD: 56 ± 6 y), we examined how the menopausal transition alters the circadian rhythm of core temperature (T C ), and whether these changes relate to sleep composition and cardiovascular recovery (i.e., heart rate and heart rate variability). Additionally, we evaluated whether sleeping on an active temperature-regulated mattress cover (ATR) could improve circadian rhythm and sleep. Men and women demonstrated a blunted core temperature rhythm during sleep, which was restored when sleeping with ATR as a result of increased amplitude and lowered mesor of the T C . These T C changes significantly related to improvements in cardiovascular recovery during sleep (3% lower heart rate and 11% higher heart rate variability, on average). Although improvements in T C and cardiovascular recovery did not uniformly translate to changes in sleep composition, restoring the U-shaped T C curve has been linked to benefits in metabolic flexibility and cognition. Together, these findings support ATR as a promising non-pharmacological strategy to restore T C rhythmicity and improve cardiovascular recovery during sleep in older adults, including postmenopausal women.