Is there any benefit to strengthening my breathing muscles?

Saturday, July 16, 2011 • Chicago, IL 60657


t makes perfect sense: to avoid getting out of breath, you should improve your breathing muscles. When you inhale, you use the muscles of the chest wall and diaphragm to suck in air; you then relax those  muscles to pus air back out. After strenuous exercise, those muscles can fatigue. That’s the observation that spurred British researcher Alison McConnell of Brunel University in London to develop the Powerbreathe “inspiratory muscles trainer” in the 1990s, a portable device that looks like an oversized asthma inhaler, designed to strengthen the muscles you use to inhale, just as weights strengthen your arm muscles. Taking 30 breaths through the machine twice a day, and gradually increasing the resistance, is supposed to strengthen the muscles, increase endurance, and make you feel less out of breath.

            There’s just one problem. Initial studies by a variety of researchers ailed to find any benefits from inspiratory muscles training, though subjects often reported feeling less out of breath. After testing classic laboratory measures of aerobic endurance like VO2max with no success, many researchers concluded that breathing isn’t a limiting factor in endurance after all – that the limits are instead determined by your ability to circulate oxygen through the blood, or your muscles’ ability to make use of that oxygen. The exception is people with conditions like chronic obstructive pulmonary disease, where this kind of respiratory exercise has long been standard.

            But athletes are more concerned with how they perform in competition than in the lab, and several more recent studies have demonstrated small but significant benefits in sports like swimming, cycling, and rowing. For example, a 2010 study at Auckland University of Technology in New Zealand put 16 competitive swimmers through a six-week Powerbreathe training program; half of them did the real thing, while the other half used the same device but were given a training program that didn’t actually strengthen their inspiratory muscles? The experimental group improved by 1.7 percent in the 100-meter freestyle and 1.5 percent in the 200 meters compared to the sham training group, but didn’t show significant improvement in the 400 meters.

            Swimmers are good candidates for this type of training for several reasons: they have to control their breathing rate to match their stroke, and they have to overcome water pressure to expand their chests when they inhale. Rowers also facet eh challenge of synchronizing their breathing to their stroke rate. But even cyclists, who don’t face the same constraints, have shown improvements of 2.7 to 4.6 percent in time trials ranging from 20 to 40kilometers after inspiratory muscle training. And a 2010 study by researchers in Hong Kong saw improvement in the series of repeated 20-meter shuttle springs when the subjects did twice-daily inspiratory muscle training. The runners also warmed up before workouts and testing sessions with a slightly easier breathing routine.  

            There are several plausible theories of why this form of training should work, the simplest being that stronger breathing muscles allow you to pump in more oxygen when you’re tired. Even if breathing rate isn’t a limiting factor, it may be that stronger breathing muscles require less oxygen-rich blood to fuel them, allowing it to be diverted to arm and leg muscles. A more subtle possibility is that the primary benefit is how you feel – which would explain the initial failure to find improvements in laboratory studies. If theories about fatigue originating in the brain are correct, then feeling less out of breath could allow you to keep pushing for longer, even if there’s’ no actual difference in the functioning of your lungs or other parts of your body.

            The downside of the “it’s how you feel” theory is that the performance-enhancing effects may then fade away as you become accustomed to inspiratory muscle training. Clearly, much more research will be needed before we really understand if and how this technique works. Until then, unless you’re an elite athlete searching for an extra hundredth of a second, you’re probably better off focusing your time and energy on a more traditional form of breathing training with proven results: swimming or running or biking until you’re out of breath.