The Effect of Training Time (Morning and Evening) on Blood and Coagulation Indices in Young Athletes: A Quasi-experimental Study

Background and Aim: Exercise and physical activity are crucial for maintaining general health. One of the new topics in the field of exercise physiology is the investigation of the effect of exercise time (morning or evening) on the physiological responses of the body. This study aimed to investigate the effect of exercise time (morning and evening) on changes in blood and coagulation indices in young athletes. Materials and Methods: This quasi-experimental study was conducted with a pre-test and post-test design. Thirty young male athletes were randomly divided into two exercise groups: morning (۸-۱۰ AM) and evening (۵-۷ PM). The exercise program was conducted for ۶ weeks and in ۳ weekly sessions, including aerobic and resistance exercises. Blood sampling was performed in two stages, and blood indices, including white blood cells, red blood cells, platelets, fibrinogen, and thromboplastin time, were measured. The data were analyzed using a paired t-test and analysis of covariance. Results: Training in the morning and evening resulted in significant improvements in blood and coagulation indices (P<۰.۰۵). The number of white blood cells increased more in the evening group, and the thromboplastin time decreased more in the morning group. No significant difference was observed in the changes in red blood cells, platelets, and fibrinogen between the two groups. Conclusion: Training time can affect certain blood and coagulation indices. Evening training stimulates the immune system more and morning training appears to have a stronger effect on accelerating coagulation processes. These findings can be used by coaches and sports specialists in planning sports training, especially for endurance and martial arts athletes.

کلیدواژه ها:

Exercise ، Circadian rhythm ، Blood physiological phenomena ، Athletes ، Hematology