Pattern of Habitual Physical Exercise in Myasthenia Gravis Patients

Notwithstanding the amount of deliberate exercise, the daily patterns of active versus sedentary behavior have a major influence on health outcomes [1]. Patterns of habitual active and sedentary behavior in Myasthenia Gravis (MG) patients, as well as their possible relations to disease activity, are not known.

To evaluate baseline patterns of physical and sedentary behavior in MG patients.

Activity patterns of twenty-seven MG patients were assessed by a Dynaport MoveMonitor (McRoberts) accelerometer, worn for seven consecutive days. The amount of time spent in moderate and vigorous intensity activities, physical activity level (PAL), number of steps/day and sedentary time were assessed and correlations to disease severity were analyzed. The results were compared to general recommendations and published data of healthy individuals and to data of patients with the chronic disorders chronic obstructive pulmonary disease (COPD) and mitochondrial myopathy.

MG patients had sedentary behavior during 78±7% of the day. There was neither a correlation between disease severity and number of steps/day (R = -0.15; p = 0.56) nor between disease severity and PAL (R = 0.33; p = 0.26). Nevertheless, the MG patients met the recommendations of daily deliberate exercise (181±158 MET min/day). PAL was lower in MG patients (1.5±0.138) than in healthy individuals (1.67±0.145, p < 0.00001).

Although a majority of MG patients meet the recommendations of deliberate exercise, their baseline physical activity levels are dominated by sedentary behavior. In comparison with a healthy population, MG patients are less physically active, but the reason for this remains unclear with no correlations between disease severity and physical activity patterns.