Associations between heart rate and physical activity in people with post-COVID-19 condition accounting for myalgic encephalomyelitis/chronic fatigue syndrome symptoms.

Abstract

Tachycardia after mild activity or during rest is a common complaint among people with post-COVID-19 condition (PCC). Understanding the relationships between heart rate (HR) and physical activity (PA) in this population is crucial for developing appropriate rehabilitation protocols. To investigate the associations between HR and PA in individuals with PCC, accounting for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) symptoms. Observational study. Sixteen adults with PCC (81% females, mean age 51 ± 12 years). Participants were instructed to use 2 wearable devices (Garmin smartwatch and ActiGraph accelerometer) during waking hours over 4 days while performing daily activities. Average HR, percentage of time in tachycardia (time with HR > 100 bpm), and daily step count were assessed. The accelerometer counts per minute was used to categorize daily PA as sedentary, light intensity, and moderate-to-vigorous (MVPA). Participants wore the watches and accelerometers for a mean of 11.36 ± 2.60 and 12.51 ± 1.94 h per day, respectively. Average daily HR increased with increasing PA levels from sedentary to MVPA. However, the percentage of time in tachycardia was significantly lower during periods of MVPA compared with sedentary periods, even after adjusting for ME/CFS symptoms. Individuals with PCC in our study experienced more tachycardia during periods of minimal physical activity compared with periods categorized as MVPA.