Physical activity levels in myalgic encephalomyelitis/chronic fatigue syndrome before and after a 2-day cardiopulmonary exercise test protocol

Objective: This study characterized physical activity levels in people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MECFS) before and after a 2-day cardiopulmonary exercise test (CPET) protocol. Activity levels of people with MECFS were compared to sedentary controls and separated into day and night activity to elucidate circadian differences.Methods: People with MECFS (n = 58) and sedentary controls (CTRL; n = 41) completed a 2-day CPET. For six days prior to testing and 10 days following testing, participants wore an ActiGraph GT3X-BT accelerometer on the dominant wrist to track daily activity. Physical activity intensity was separated into sedentary, light, and moderate/vigorous zones based on accelerometry cut-off points. Linear mixed effects models were used to compare differences in activity levels between groups.Results: People with MECFS spent significantly more time in sedentary activity and less time in light and moderate/vigorous activity compared to the control group. These differences persisted when further separated into daytime and nighttime hours.Conclusion: Those with MECFS spend a larger portion of their day in sedentary activities compared to sedentary controls. MECFS also spend comparatively less time in light-vigorous activities throughout the day, suggesting that people with MECFS are overall generally much less physically active than sedentary otherwise healthy individuals.