Forced respiration during the deeper water immersion causes the greater inspiratory muscle fatigue in healthy young men

Comparison of respiratory muscle strength in individuals performing continuous and noncontinuous walking exercises in water after the 6-week program

This study aimed to compare respiratory muscle strength in individuals performing continuous and noncontinuous walking exercises in water after the 6-week program. Twenty-nine healthy men were randomly divided into a continuous group (CG, n=14) and a noncontinuous group (NG, n=15). Firstly, both groups executed the 6-week program which set them to walk for 30 min, 4 times per week, over 6 weeks in a pool with the adjusted intensity that their walking speed increased the heart rate to 60% of the predicted maximum. After the 6-week program, participants in the CG continued the water-walking program for 4 weeks while those in the NG discontinued the water-walking program. In both groups, respiratory muscle strength evaluated by maximum inspiratory pressure (PImax) and maximum expiratory pressure (PEmax) increased significantly after the 6-week program compared with pre-exercise value. Compared to the value after the 6-week program, PEmax increased significantly in the CG after 10 weeks (P<0.05), but the PImax showed no significant change. Compared to the value after the 6-week program, after 10 weeks, in the NG, PEmax decreased significantly, with a considerable decrease after 9 and 10 weeks compared to the CG (P<0.05). The PImax in the NG significantly decreased after 10 weeks from the value observed after the 6-week program. We demonstrated that 6 weeks of walking in water at 60% of the predicted maximum heart rate enhances PImax and PEmax, and that PImax and PEmax decrease in 4 weeks without a water-walking program.

Impact of continuous positive airway pressure on the pulmonary changes promoted by immersion in water

OBJECTIVE

To determine whether different levels of CPAP improve the lung volumes and capacities of healthy subjects immersed in water.

METHODS

This was a randomized clinical trial, conducted between April and June of 2016, involving healthy female volunteers who were using oral contraceptives. Three 20-min immersion protocols were applied: control (no CPAP); CPAP5 (CPAP at 5 cmH2O); and CPAP10 (CPAP at 10 cmH2O). We evaluated HR, SpO2, FVC, FEV1, the FEV1/FVC ratio, peak expiratory flow rate (PEFR), and FEF25-75%) at three time points: pre-immersion; 10 min after immersion; and 10 min after the end of each protocol.

RESULTS

We evaluated 13 healthy volunteers. The CPAP10 protocol reversed the restrictive pattern of lung function induced by immersion in water, maintaining pulmonary volumes and capacities for a longer period than did the CPAP5 protocol.

CONCLUSIONS

When the hemodynamic change causing a persistent lung disorder, only the application of higher positive pressures is effective in maintaining long-term improvements in the pulmonary profile.