Abstract

ABSTRACT: BACKGROUND: Physical exercise is important for promotion of the immune system. The immune responses to exercise are dependent on the intensity and duration of the exercise performed. During exercise, metabolic and hormonal changes occurred that can induce lymphocyte apoptosis. Melatonin is one of the hormones that are affected by exercise, it is a pineal gland hormone, its production and secretion followed a circadian pattern, onset of darkness stimulate its secretion, while day light suppress its production. Melatonin is regarded as an anti-aging hormone; it has a role in the elimination of harmful lymphocytes which may give rise to chronic inflammation and possibly to autoimmunity. OBJECTIVE: This prospective study aimed to elucidate the effect of moderate endurance exercise on melatonin hormone and the percentage of peripheral blood lymphocyte apoptosis in healthy subjects. METHODS: Sixty healthy subjects with a mean age of (37.05 ± 13.02) year, participated in the study. They were subjected to moderate exercise session which lasted for 60 min and repeated 3 times per week for 3 months. The exercise intensity was 50-60% of heart rate reserve (according to Karvonen formula). Two exercise stages were performed; the first stage include 30 minute of physical activity program and the second stage include 30 minute of treadmill exercise. Blood sample were collected before and after exercise to examine its effect on the level of melatonin hormone and apoptosis of peripheral blood lymphocyte. RESULTS: This study showed significant increment in the level of melatonin hormone and the percentage of lymphocyte apoptosis after exercise in comparison to pre exercise values for each week along the period of the test (P < 0.05). Three months exercise showed a significant correlation with the levels of melatonin hormone (P= 0.008, r= 0.44), and with percentage of lymphocyte apoptosis (P = 0.001, r= 0.701). CONCLUSION: It can be concluded that moderate exercise for three months was associated with increased percentage of periphral blood lymphocyte apoptosis and increased level of melatonin hormone in the first two months while in the third month this anti aging hormone had reached a steady state after the subjects get trained to exercise