The Investigation of the Effects of Melatonin on Electrocardiografic Findings in Rats Undergoing Acute Intense Exercise

Aim: Acute intense exercise causes an additional strain on cardiovascular system. Melatonin has been known as a hormone with cardiovascular protective effects. The aim of this study is to investigate the protective effects of melatonin on cardiovascular changes in rats undergoing acute intense exercise, considering electrocardiogram (ECG) results. Materials and Methods: The 3-5-month-old 28 Wistar albino rats were used in this study and they were divided into 4 groups. The vehicle injection was applied in the control group without any exercise procedure. The groups of exercise, exercise+melatonin (intraperitoneal injection of melatonin at the dose of 10 mg/kg before exercise) and exercise+melatonin+luzindole (intraperitoneal injection of luzindole at the dose of 0.4 mg/kg and melatonin at the dose of 10 mg/kg before exercise) were run on treadmill until they were tired. ECG recording was performed at the end of the exercise. Results: A significant increase in heart rate was observed in both exercise groups. The decreasing effect of melatonin on QT and QTc prolongation in the exercise group was reported; however, this effect did not occur in the luzindol administrated group. Melatonin also decreased corticositerone levels, which increased with exercise, independent of receptor. White blood cell and neutrophile counts of the melatonin administrated group were observed to be close to that of the control group. Conclusion: These results indicate that melatonin can be used as an agent that may decrease unfavorable effects of exercise and improve the quality of exercise.