Melatonin is an Ergogenic Aid for Exhaustive Aerobic Exercise only during the Wakefulness Period

• Grant number: 15/19878-1
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: November 01, 2015
• End date: February 29, 2016
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Wladimir Rafael Beck
• Grantee: Wladimir Rafael Beck
• Host Institution: Faculdade de Ciências Aplicadas (FCA). Universidade Estadual de Campinas (UNICAMP). Limeira , SP, Brazil

Abstract

This study tested the ergogenic effects of acute administration of melatonin on exhaustive exercise (tlim) at the anaerobic threshold intensity (iAnT) during periods of lower (L) and higher (H) spontaneous physical activity in swimming rats. Additionally, we evaluated the time of day effect on aerobic exercise tolerance. The periods of L and H were determined gravimetrically. All animals were subjected to an incremental test to determine the iAnT. Melatonin was administered (10 mg.kg-1, intraperitoneal) and after 30 minutes, the rats were subjected to tlim during the L (LM) or H (HM) period. Control groups were called LC and HC. The criterion of significance was 5%. Melatonin enhanced tlim by 169% during H (HC = 72 min; HM = 194 min; P < 0.01; ES = 1.23) and by 90% during L (LC = 31 min vs LM = 59 min; P = 0.39; ES = 1.18), demonstrating a significant effect on tlim (F = 10,35; P < 0.01) and a strong effect size (ES). Additionally, tlim was higher during H (F = 14.24; P < 0.01). Melatonin is a reasonable ergogenic aid, particularly during the wakefulness period, and the exercise tolerance is dependent on the time of day for swimming rats. (AU)