Artificial Co 2 -water Immersion Facilitates Recovery From Muscle Fatigue Caused By High Intensity Anaerobic Exercise

Abstract

In response to the CO2-water (CO2≥1000 ppm) immersion, the reduction of sympathetic nerve activity may imply the facilitation of muscle fatigue recovery. PURPOSE: In the present study, we investigated whether the whole body bath with CO2-water influences recovery of the muscle fatigue after high intensity exercise. METHODS: The healthy male college students (n=6, 18-21yrs, 171.3±6.7cm, 73.6±13.0kg) participated in this study. The cycle ergometer work tests lasting 30 seconds were used to estimate anaerobic power with leg pedaling exercises. Exercise loads of the tests were 0.075kp per body weight. Anaerobic power was determined by measuring the highest power output during 30 seconds. Core temperature (CoreT) and ECG were recorded continuously throughout the experiment. The subjects performed 30-s maximal pedaling exercise, and took bath in tap- or CO2-water at 35 °C for 10 minute after exercise. Subjective thermal sensation (TS) in the body bath was also recorded. Vastus lateralis (VL) dominant muscle hardness using the elastography. , muscle pain by visual analog scale (VAS), and blood lactate (BLa) and were evaluated at pre- and immediately after-exercise, and at 10 min after exercise. RESULTS: The strain ratio (SR) between the VL and a reference material was calculated. TS in the CO2-water was significantly higher than in the tap-water (tap-water vs. CO2-water, -0.17±0.76 vs. 1.17±0.41, p<0.01). At 10 min in recovery, in the CO2-water compared with the tap-water, SR significantly decreased quicker (0.49±0.25 vs. 0.91±0.25, p<0.01). However, there was no significant difference in CoreT, BLa and VAS between these two water kinds. CONCLUSIONS: We reported previously that the muscle blood flow in the immersed part was larger in CO2-water than tap-water of a same temperature. In addition to a local effect of CO2, suppression of muscular sympathetic activity may also contribute to the increase in local blood flow. Facilitation of muscle hardness recovery shown in this study might be caused by the increased muscle blood flow. The present results suggested that CO2-water immersion may contribute to rapid recovery from the muscular hardness induced by high intensity exercise.