Circadian rhythm effect on military physical fitness and field training: a narrative review

Abstract

Disruption of the circadian rhythm also has significant influences on the exercise function. Therefore, the aim of this study was to review the effects of circadian rhythm on physical fitness and athletic performance in military personnel. An online search was done in web of science (WoS), Ovid, Scopus and PubMed (MeSH) databases with the following combination of keywords: “chronobiology” AND “performance of military” AND “exercise”. A total of articles were identified, physical fitness and sport performance of military forces is severely affected by the science of chronobiology and 24-h circadian rhythm. In humans, these articles showed circadian rhythm with affects on performance of various organs in the body, such that the body temperature, heart rate, hormonal secretion, electrolyte excretion, blood pressure, plasma tyrosine concentrations, free amino acids, cholesterol production and even behavior can affect physical fitness and athletic performance in the military force. Based on the analyzed articles, it is concluded that circadian rhythm has a significant effect on exercise performance, aerobic and anaerobic power, muscular endurance and flexibility, and hormonal secretion. For this reason, it is recommended to the organizers of the competitions and coaches should take into consideration the effects of circadian rhythm on the athletic performance of the military, the scheduling of competitions and exercises.