0160 Resistance Exercise in the Luteal Phase Promotes Heat Loss and Increases Delta Power During Nocturnal Sleep

Introduction Fluctuation in body temperature rhythm are associated with the menstrual cycle and closely relate to sleep. In particular, during the luteal (high temperature) phase (LP), sleep quality during nocturnal sleep decreases and daytime sleepiness increases. Menstrual cycle-related sleep disturbance can negatively impact a woman’s social life. In this study, we investigated the effect of exercise on body temperature, heat loss, nighttime sleep, delta power, and subjective evaluation during the follicular phase (FP) and LP in young-adult women. Methods Twelve young-adult females participated in the experiment for a total of 4 days over the course of their menstrual cycle: 1) FP non-exercise condition, 2) FP exercise condition, 3) LP non-exercise condition, and 4) LP-exercise condition. Exercise consisted of 40 minutes of resistance exercise training (RT) at 70% one repetition maximum during the day. Electroencephalography (EEG), electro-oculography, chin surface electromyography, skin temperature, and tympanic temperature were measured simultaneously at the subject’s home overnight, and distal-proximal-skin-temperature-gradient was calculated. Sleep EEG data were scored for 30 s epoch periods according to the American Academy of Sleep Medicine Scoring Manual by a registered polysomnographic technologist. Power spectral analysis using the fast Fourier transform (FFT)algorithm was conducted. The study was approved by the Ethics Committee of Saitama Prefectural University. Results RT promoted heat loss and increased stage N3 sleep during nocturnal sleep in both the FP and LP. When the distribution of stage N3 duration and delta-power in the sleep period was analyzed, stage N3 sleep and delta power persistence occurred in the second half of the nocturnal sleep period, especially in the LP-exercise condition. The heat loss was also higher and coincided with the increase of delta power in the LP-exercise condition. Conclusion RT promoted heat loss, slow wave sleep, and delta power also in the latter half of the nocturnal sleep in the LP, when body temperature is higher and heat loss are disrupted. Encouraging RT during the LP may help women to overcome sleep disturbance associated with this phase of the menstrual cycle. Support (if any)