Effects of circadian rhythm on balance performance

Aim: Circadian rhythm changes that occur in the human body in a 24 hour period affect many sporting abilities. The aim of the study was to examine the circadian rhythm effect on dynamic balance performance and to determine the role of physical activity level, body temperature, sleep state and sex on this possible effect. Methods: Forty-two volunteers from 18 to 25 years of age with different physical activity levels participated in the study. The dynamic equilibrium test, Star Excursion Balance Test, was conducted under standard laboratory conditions at 09:00, 13:00 and 17:00 on three different days with at least two days interval. The physical activity level and sleepiness status of the participants were determined by the relevant questionnaires. Before each test, oral body temperatures were measured. Results: The best balance test scores were found in the lunch and evening, in the male and the trained group; the body temperature changes were increased parallel to these results; while for dominant leg in anterior, non-dominant leg was found to be significantly different in posterior test directions. The condition of sleepiness has not been affected by this process. Conclusion: Circadian rhythm effect was determined in dynamic balance performance, and it was found that oral body temperature, gender, physical activity level also played a role in this effect. Key words: Balance, postural control, circadian rhythm, star excursion balance test.