ABSTRACT
<b>Background</b>: A 30-60 min rest after exercising is generally recommended before taking a bath. Although this was considered an appropriate bathing method, effects of pre-bath rest on recovery from exercise fatigue remain unclear. Here, we aimed to examine the effects on fatigue recovery of pre-bath rest after a workload, with the focus on changes in lactic acid levels. <BR><b>Methods and Results</b>: Ten healthy adult men increased their blood lactic acid levels through a treadmill workload performed in accordance with the Bruce method, then took either a 60-min post-workload rest followed by a 10-min full-immersion 38°C bath (Experiment A) or a 10-min full-immersion 38°C bath followed by a 60-min rest (Experiment B). Body temperature, blood pressure, pulse rate, and blood lactic acid level were measured at three time points: before workload (Test 1), after workload (Test 2), and after bathing/resting (Test 3). Decreases and percent decreases in blood lactic acid levels were calculated by comparing Test 3 results with Test 2 results. These calculated values and the measured values in three tests were compared between Experiment A and Experiment B using paired-t test. There were no significant differences in maximum systolic blood pressure, maximum diastolic blood pressure, maximum workload attained, and maximum pulse rate measurements between Experiment A and Experiment B. Differences in systolic blood pressure and diastolic blood pressure measurements in Tests 1, 2, and 3 were not significant. The pulse rates measured at the final measurement (Test 3) were significantly higher in Experiment A than in Experiment B (90.4 ± 18.2 bpm vs 79.6 ± 11.6 bpm, p = 0.04). No significant differences were observed in other measurement timings. The body temperature measurements at the final measurement were slightly higher in Experiment A than in Experiment B (36.4 ± 0.4 vs 36.1 ± 0.3°C, p = 0.05). No significant differences were observed in other measurements. Blood lactic acid levels before workload (Test 1) were significantly higher in Experiment A (6.6 ± 4.7mmol/L) than in Experiment B (2.0 ± 1.4 mmol/L, p = 0.02), but those at other measurement points (Test 2 and Test 3) were similar. Neither decreases nor percentage decreases in blood lactic acid levels differed between Experiment A and Experiment B.<BR><b>Conclusions</b>: Resting before a post-exercise bath did not change the decreases or percent decreases in blood lactic acid levels after bathing at 38°C, suggesting negligible effects of pre-bath resting on recovery from exercise fatigue.
ABSTRACT
Background: A 30-60 min rest after exercising is generally recommended before taking a bath. Although this was considered an appropriate bathing method, effects of pre-bath rest on recovery from exercise fatigue remain unclear. Here, we aimed to examine the effects on fatigue recovery of pre-bath rest after a workload, with the focus on changes in lactic acid levels. Methods and Results: Ten healthy adult men increased their blood lactic acid levels through a treadmill workload performed in accordance with the Bruce method, then took either a 60-min post-workload rest followed by a 10-min full-immersion 38°C bath (Experiment A) or a 10-min full-immersion 38°C bath followed by a 60-min rest (Experiment B). Body temperature, blood pressure, pulse rate, and blood lactic acid level were measured at three time points: before workload (Test 1), after workload (Test 2), and after bathing/resting (Test 3). Decreases and percent decreases in blood lactic acid levels were calculated by comparing Test 3 results with Test 2 results. These calculated values and the measured values in three tests were compared between Experiment A and Experiment B using paired-t test. There were no significant differences in maximum systolic blood pressure, maximum diastolic blood pressure, maximum workload attained, and maximum pulse rate measurements between Experiment A and Experiment B. Differences in systolic blood pressure and diastolic blood pressure measurements in Tests 1, 2, and 3 were not significant. The pulse rates measured at the final measurement (Test 3) were significantly higher in Experiment A than in Experiment B (90.4 ± 18.2 bpm vs 79.6 ± 11.6 bpm, p = 0.04). No significant differences were observed in other measurement timings. The body temperature measurements at the final measurement were slightly higher in Experiment A than in Experiment B (36.4 ± 0.4 vs 36.1 ± 0.3°C, p = 0.05). No significant differences were observed in other measurements. Blood lactic acid levels before workload (Test 1) were significantly higher in Experiment A (6.6 ± 4.7mmol/L) than in Experiment B (2.0 ± 1.4 mmol/L, p = 0.02), but those at other measurement points (Test 2 and Test 3) were similar. Neither decreases nor percentage decreases in blood lactic acid levels differed between Experiment A and Experiment B. Conclusions: Resting before a post-exercise bath did not change the decreases or percent decreases in blood lactic acid levels after bathing at 38°C, suggesting negligible effects of pre-bath resting on recovery from exercise fatigue.