The short-term effects of melatonin supplement consumption on some cardiac parameters of active young women before, during and after exhaustive activity

The reduction of melatonin is associated with the increase in vasoconstriction and blood pressure (BP). The purpose of this study was to investigate the effect of short-term melatonin consumption (MC) on some cardiacparameters of young women during rest،immediately after exercise and during recovery. This semi-experimental study was done in Mashhad. Active young women (24people) voluntarily participated in the study،and were randomly divided into two groups of MC and placebo groups. During rest condition،BP and body temperature were measured and heart contractility and hemodynamic parameters were measured using the cardio screen system. Then Bruce protocol was conducted on the treadmill until exhaustion phase. In the recovery،the subjects walked on the treadmill and at the fifth minute cardio-screen indicators and blood pressure were recorded. For one week،experimental group took 3milligram melatonin tablets and placebo group took 3milligram of placebo tablets every night. On the ninth day of luteinizing،the tests were repeated again and by using paired t-test and ANOVA test the following findings were obtained (p<0. 05). There were a significant difference (SiDi) between two groups in BP changes in the «recovery» and Heart Rate (HR) and Systemic Vascular Resistance index (SVRI) changes in all the three phases. There was a SiDi in the Acceleration Index (ACI) and Velocity Index (VI) changes in the «right after exercise» and «recovery»، so that the increase in VI and ACI in MC group was more than the increase in placebo group. There was no SiDi in the amount of Left Ventricular Ejection Time (LVET) changes in three conditions. According to the results،MC reduces the pressure on cardiovascular system during the activity and increases the efficiency of recovery.