Respiratory muscle training leads to strong, sustained results

Participants who underwent respiratory muscle training for 5 weeks had sustained, improved results after not training for the same amount of time, according to study results published in Experimental Physiology.

Such improvements may be especially helpful for patients with chronic lung conditions, according to the researchers.

“Our findings indicate that the benefits of inspiratory muscle training seem to persist as long as the strength of the respiratory muscles is elevated above baseline,” Paolo B. Dominelli, PhD, assistant professor in the department of kinesiology and health sciences at the University of Waterloo, told Healio. “Periodic respiratory muscle training may potentially be helpful.”

Dominelli and colleagues evaluated 16 healthy adults to find out if results from respiratory muscle training for 5 weeks are maintained when directly followed by 5 weeks of no training. They specifically looked for reductions in respiratory muscle metaboreflex, which is when the body limits blood flow to the limbs because the breathing muscles have reached exhaustion, according to a press release from The Physiological Society.

Of the total cohort, eight adults (mean age, 26 years; men, n = 6) received 5-week inspiratory muscle training at 50% maximal inspiratory pressure (MIP) and tibialis anterior (TA) training at 50% maximal isometric force for 5 days a week directly followed by no training for 5 weeks. The remaining eight adults (mean age, 24 years; men, n = 7) did not receive any intervention.

Researchers also collected patients’ heart rate and mean arterial blood pressure while they completed a loaded breathing task to failure, or 60% MIP, prior to training, after 5 weeks of training and after 5 weeks of no training, using iso-time (final minute from pre-training trial) to fairly compare heart rate to results from the three separate loaded breathing tasks.

In the group that underwent training, researchers observed improved MIP (18% ± 9%; P < .001) and dorsiflexor maximal force (34% ± 19%; P < .001) measures after 5 weeks. Compared with these measurements, 5 weeks of no training did not greatly impact MIP (17% ± 7%, P < .001) and TA (33% ± 18%, P < .001), suggesting sustained results despite not participating in strength training for 5 weeks.

In terms of metaboreflex, inspiratory muscle training decreased mean arterial blood pressure after training (–11% ± 17%; P = .003), and this was mostly sustained after 5 weeks of no training (–9% ± 9%; P = .007). This finding signals that patients who participate in the training can exercise for longer periods of time without the feeling of exhaustion, according to the release.

For all three times researchers performed the loaded breathing task, adults who received no intervention demonstrated no changes in MIP, TA strength or iso-time mean arterial blood pressure.

According to the press release, these findings may be helpful to inform pulmonary rehabilitation programs that include inspiratory muscle training, as such training may help relieve symptoms of patients with conditions such as COPD.

“Future studies will need to focus on two additional directions,” Dominelli told Healio. “First, the detraining period needs to be longer to see how long the benefits persist. Second, our current study was done with young healthy participants who are not limited by their respiratory muscles. Follow-up studies are needed in different patient groups who have pulmonary disease.”

For more information:

Paolo B. Dominelli, PhD, can be reached at paolo.dominelli@uwaterloo.ca.

Reference:

• Breathing muscles remain stronger even after weeks of no training; preserved health gains could improve physical endurance and quality of life for people with chronic lung conditions. https://www.physoc.org/news_article/breathing-muscles-remain-stronger-even-after-weeks-of-no-training/. Published Feb. 9, 2023. Accessed Feb. 8, 2023.