But how exactly does that work? What are the most effective methods to train respiratory muscles? And what are the measurable outcomes? A range of studies has looked at these questions from different angles over the last years, and the results were recently collected and analyzed in a meta-analysis, in order to extract the most powerful evidence.
Researchers from the ETH Zurich evaluated 236 relevant articles, and included 49 studies into their analysis. After quality control, 8 studies met the inclusion criteria for in-depth analysis .
The overall conclusions confirm the effectiveness of respiratory muscle training (RMT) to improve exercise performance:
- RMT improves exercise performance
- The average overall improvement in performance was 11%. The sharpest increases in performance were seen in constant load tests (21% improvement).
- Less fit individuals experience a steeper incline in performance compared to highly trained athletes. This is due to a shorter time to respiratory muscle fatigue in untrained subjects, which is increased by RMT.
- RMT improves exercise performance independent of RMT method
- The two main methods used are respiratory muscle strength training and respiratory muscle endurance training. Both methods resulted in a comparable impact on performance.
- Providing a combination of inspiratory and expiratory muscle training proved superior to training inspiratory or expiratory muscles only.
- RMT improves exercise performance independent of type of exercise
- RMT elicits increase in performance in endurance sports such as cycling or running, as well as in intermittent sports such as soccer or basketball.
Analysis of all relevant high-quality data shows that RMT effectively improves exercise performance, with combined inspiratory and expiratory muscle training being most effective.
The rationale for training both aspects of the breath cycle is twofold:
Exercise causes respiratory muscle fatigue, leading to dyspnea (breathlessness), which is the major reason to stop exercise. Inspiratory and expiratory muscles are equally affected by respiratory muscle fatigue.
Overload of the respiratory muscles trigger the metaboreflex, reducing blood flow to the limbs and thus impairing exercise performance, eventually leading to exercise attenuation. Both inspiratory and expiratory muscles elicit the metaboreflex.
These two points underscore the importance of training both inspiratory and expiratory muscles for optimal impact on exercise performance. The Breather is one of the few devices available that trains both parts of the breath cycle.