May 2007 What causes the inspiratory muscles to become weak?
Weakness of the inspiratory muscles can result from a number of causes, including disease, but a potent influence upon their condition is the amount of exercise they receive. The phrase ‘use it or lose it’ applies equally well to the inspiratory muscles as it does to your leg muscles. If you get out of breath on the stairs, then you’ll take the lift, with the consequence that your inspiratory muscles get less exercise. As they become weaker, the level of physical activity that brings on the breathlessness gets lower, so you avoid the stairs even more…it’s a vicious cycle of breathlessness, lack of exercise and inspiratory muscle weakness. In addition, the use of oral steroid medication (not inhaled steroids) to control lung inflammation in conditions such as asthma and emphysema has been shown to cause weakness of the inspiratory muscles. This weakness can impair lung function and can be counteracted by inspiratory muscle training. N.B. inhaled steroids do not cause inspiratory muscle
