Comparison of the effect of aerobic exercise in water with two different temperatures with outside water environment on the index of very low frequency waves of heart rate variability in active young men

Introduction and purpose: Cardiac response to body core temperature variation measured with the very low-frequency parameter of heart rate variability. The aim of this study was to investigate the variability of very low frequency due to different temperatures of aerobic training in water and dry. Materials and methods: 40 academic active male were selected as research subjects. Then, all subjects were randomly divided into different groups of research (control=10; aerobic training on a treadmill=10; aerobic training in water with normal temperature=10 and aerobic training in hot water=10). In the pre-test and after the intervention, the parameter of very low frequency was measured using a heart rate monitor Holter. In order to compare differences in the research stages, analysis of variance in repeated measures was used. Results: The results of this study showed that compared with control group, performing 21 consecutive days aerobic exercise in drought conditions at 20°C significantly increased in values of low-frequency waves (P=0.02) and very Low frequent (P=0.04). Performing aerobic exercise in water at 29°C in values of low frequency waves (P=0.21) and very low frequency (P=0.35) and water at 39 ° C in values of low frequency (P=0.18) and very low frequency (P=0.41) does not change significantly. Discussion and Conclusion: In conditions of dry aerobic exercise due to sweating, surface and the central temperature reduced and the heart rate variability increased. The condition of the aquatic environment and different water temperatures do not have significant effect on heart rate variability.