Influence of Aerobic Exercise on Sleep and Salivary Melatonin in Men

Abstract

Background: Insomnia is a sleep disorder that affects ap proximately 50-70 million US adults. Previous studies have examined the impact of exercise as a non-pharmacologic mechanism for improving sleep and reducing insomnia. The body’s melatonin secretion is considered an internal sleep regulator (as opposed to external sleep regulators such as medications) and may be improved by regular exercise. Therefore, the purpose of this study was to evaluate the ef fect of an 8-week aerobic exercise intervention on nighttime salivary melatonin concentrations and self-reported sleep quality in a cohort of adult men. Methods: Utilizing an experimental pre-test post-test de -sign, 17 previously sedentary men ages 18-44 years com pleted 8 weeks of moderate-intensity aerobic exercise. Sleep Quality and was assessed pre-intervention and post-inter vention using the Pittsburgh Sleep Quality Index (PSQI). Salivary melatonin concentrations were assessed pre-inter vention, mid-intervention, and post-intervention at 20:00h, 22:00h, and 03:00h using Enzyme-Linked Immunosorbent Assay (ELISA) techniques. Paired sample t-tests were used to compare changes in PSQI scores from pre-intervention to post-intervention, as well as to compare salivary concen trations at 20:00h, 22:00h, and 03:00h during the pre-inter vention, mid-intervention, and post-intervention collections. Results: PSQI scores significantly decreased from pre-in tervention to post-intervention, indicating significant im provement in sleep quality (p = 0.046). Salivary melatonin concentrations increased significantly from pre-intervention to post-intervention at 20:00h, as well as from 20:00h to 3:00h within the post-intervention collection period (p 0.015-0.037). Conclusions: Moderate aerobic exercise may increase the production of nighttime melatonin, thus improving inter nal sleep regulation and positively impacting sleep quality in previously sedentary adult men. Individuals with sleep problems may consider using exercise to improve aspects of sleep.