In this pioneering work, subjects who followed a resistance-breathing training protocol improved their respiratory muscle strength and their snorkel swimming time by 33 percent and underwater scuba swimming time by 66 percent, compared to their baseline values.

Participants randomised to a similar protocol requiring high respiratory flow rates improved their respiratory endurance and surface and underwater swimming times by 38 percent and 26 percent, respectively. The group randomised to a placebo training program, conducted with the same equipment and protocol, showed no significant improvement in respiratory or swimming performance.

"Specific respiratory muscle training could allow divers in the military, civilian rescue services, commercial enterprises and sport to perform better underwater," said Claes Lundgren, M.D., Ph.D., professor of physiology and biophysics in the UB School of Medicine and Biomedical Sciences and the study's senior author. Lundgren said that training the breathing muscles to improve the performance of swimming muscles seems counter-intuitive, but is logical physiologically.

"Typically, we think it's the muscles that move the body that are fatigued when we tire," he noted. As shown by other studies, when breathing muscles become fatigued, the body switches to survival mode and "steals" blood flow and oxygen away from the locomotor muscles and redirects it to the respiratory muscles to enable the diver to continue breathing, explains Lundgren. Deprived of oxygen and fuel, the locomotor muscles become fatigued.

"Increasing the strength and endurance of the respiratory muscles prevents their fatigue during sustained exercise, enabling divers and swimmers to sustain their effort longer without tiring," Lundgren said. He noted that this type of training also may be useful for patients who suffer from respiratory stress.

MEDICA.de; Source: University at Buffalo