Normocapnic hyperpnea is a form of endurance training for respiratory muscles.

This study reports it’s useful in people with myasthenia gravis.

First, the details.

• 10 people with myasthenia gravis participated in home-based respiratory muscle endurance training
• The patients had mild to moderate generalized myasthenia gravis.
• Normocapnic hyperpnea training was designed to achieve 50% to 60% of their maximal voluntary ventilation over 4 to 6 weeks.

And, the results.

• The training significantly increased respiratory endurance and total ventilatory volume.
• When the training was stopped, about 25% of this gain was lost after 3 to 5 months.
• Myasthenia gravis score and lung function, however, did not change.
• Patients were positive about the training effects on physical fitness and respiration.

The bottom line?
The major symptom of myasthenia gravis is muscle weakness. One example is myasthenia crisis, which involves shortness of breath. Patients in crisis have difficulty breathing, and a ventilator might be needed.

Usually breathing problems worsen over days to weeks, not suddenly, as the term “crisis” suggests. And based on this study it appears that normocapnic hyperpnea training might be helpful.

A placebo-controlled study would have provided more information. A real challenge would be to gather a sufficient number of patients to see if those using normocapnic hyperpnea training have a lower risk of crisis.

7/25/07 112:16 JR