The Effect of Melatonin Consumption on Some Heart Contractility Parameters during Exhaustive Exercise in Active Males

Melatonin has an important role in the regulation of cardiovascular system, and the reduction of melatonin is associated with an increase in vasoconstriction and finally in blood pressure and heart rate. According to the positive effect of melatonin on cardiovascular indexes, the main aim of this study was to investigate the effect of melatonin consumption on some heart contractility parameters during exercise in active men. For this purpose, 12 students of Imam Reza University(mean age 22±3, weight 72.7±9.80, BMI 23.2±2.63) were selected to participate in this study. The participants were tested once in the control group (without melatonin consumption) and once in the experimental group (with melatonin consumption). Bruce test was conducted in two different days, with 72 hours of interval at 1 p.m. and the results were recorded. After 72 hours, 10 milligrams of melatonin supplement were consumed 30 minutes before the exercise. Heart contractility indexes were measured using the cardio-screen system. The data were analyzed with SPSS 16, descriptive statistics and paired t test at p<0.05. The results of the study revealed that heart rate, systolic time ratio reduced significantly after melatonin consumption (p˂0.05). Stroke volume, blood acceleration index and blood velocity index increased significantly after melatonin consumption (p˂0.05). However, left ventricular ejection time did not change significantly (p˂0.05).Hence, it was concluded that probably 10 mg of melatonin consumption improved the pressure on cardiovascular system of males during the exercise.