What causes breathlessness?
Breathlessness is a common feature of lung and heart disease, but as we know all too well, its also a feature of normal exercise. Recent research has shown that the strength of the inspiratory muscles has a direct influence on how hard we can breathe and how breathless we feel whilst doing it. If the muscles are weakened or fatigued (inspiratory muscles can fatigue by as much as 20%) then we can’t breathe as hard and breathing requires greater effort; we experience the effort as breathlessness. A useful analogy is to think about how much heavier a barbell feels on the 12th repetition than it did on the first. In the same way, if the inspiratory muscles are weakened or fatigued, breathing feels harder.
