Effect of circadian rhythm on response of some of athlete's serum electrolytes to the submaximal PWC195 test

Purposec Time of day affects many physiological characteristics such as aerobic power, and physical practice may influence the serum electrolytes. Accordingly, the purpose of this study was to survey the effect of circadian rhythm on response of some of athlete's serum electrolytes to the submaximal PWC195 test. Materials & Methods: For this purpose, 13 subjects (age: 24.7 +/- 2.3 yr; weight: 69 +/- 3.7 kg; height: 176.5 +/- 2.6 cm) selected from physical education students at Urmia University. Subjects had did regular physical activity and sport participation (at least 3 yr). Initially, in the morning of 1st day (7: 00), after blood sampling (pre-test), subjects performed submaximal PWC195 test -as a short-duration submaximal activity- and blood samples (morning post-test) taken immediately after the test. Then, in the evening of 2(nd) day (17: 00), the test practiced again by the subjects, and final blood samples (evening post-test) taken. Finally, the blood samples analyzed to determine the concentrations of serum electrolytes (Ca++, K+, Na+ and Mg++). Results: Statistical analysis of data revealed that morning and evening submaximal PWC195 tests had no significant effects on serum electrolytes (P<0.05), and there were no significant differences between mean values of morning and evening post-tests (P<0.05). Conclusions: We concluded that, 1) short-duration submaximal activity can not change concentrations of athlete's serum electrolytes, and 2) time of day (morning or evening) has no effect on responses of serum electrolytes to this type of activity.