The effect of acute swimming exercise on plasma melatonin levels in rats

This study aims to determine the changes in plasma melatonin levels of rats performing acute swimming exercise, immediately following the exercise and after 24 and 48 hours.

The study included 40 Spraque Dawley species adult male rats divided in to 4 groups as follows: group 1: general control group, group 2: swimming group A, the animals were decapitated after performing 30-minute acute swimming exercise, group 3: Swimming group B, the animals were decapitated 24 hours after performing 30-minute acute swimming exercise and group 4: swimming group C, the animals were decapitated 48 hours after performing 30-minute acute swimming exercise. Blood samples were collected from all experimental animals by decapitation method and plasma melatonin levels were determined according to RIA method.

The comparison of plasma melatonin levels among groups revealed that group 3 had the highest plasma melatonin levels (p<0.01). The levels in group 1 (control) and group 4 were not different. The lowest plasma melatonin levels were found in group 2 (p<0.01).

The results of our study demonstrate that plasma melatonin levels that decrease immediately after acute swimming exercise increase significantly after 24 hours and restore to resting levels after 48 hours (Tab. 1, Ref. 15).