eHealth-Guided Exercise Improves Peak Oxygen Uptake and Health-Related Quality of Life After COVID-19: A Randomized Controlled Trial

Purpose: Physical activity (PA) levels declined during the COVID-19 pandemic, contributing to reduced fitness and quality of life. eHealth tools may help increase PA. In a six-month randomized controlled trial, we evaluated Activity Quotient (AQ), an innovative eHealth tool designed to promote PA and improve peak oxygen uptake (V̇O 2 peak), compared with standard advice on national PA recommendations in physically inactive adults recovering from COVID-19. Methods: Seventy-seven participants with previous COVID-19 infection were randomized 1:1 to either receive: 1) an eHealth-guided exercise intervention (n=38), using AQ to motivate for a PA dose that led to > 100 weekly AQs, or 2) a control group (n=39) advised to follow standard PA recommendations. V̇O 2 peak scaled for fat-free mass (FFM) was the primary outcome, assessed in a subsample of participants who completed clinical assessment (n=33; eHealth group n=16, control n=17), while secondary outcomes included physical and mental scores of health-related quality of life (HRQoL). Linear mixed-effects models were used to analyze the effects of the intervention. Results: Participants (79% women) were 41.4±10.0 years and had a BMI of 28.8±5.9 kg/m². Among 33 participants who completed clinical assessment, V̇O 2 peak increased 4.9 mL•kgFFM -1 •min -1 (95%CI 1.2 to 8.7, p =0.0134) more in the eHealth group compared with controls. Mental HRQoL increased by 9.8 points (95% CI 2.5 to 17.0, p =0.009) more in the eHealth group compared with controls. No between-group difference was observed in physical score of HRQoL. Conclusions: A six-month eHealth-guided exercise intervention using AQ was more effective than standard PA advice in improving V̇O 2 peak and mental HRQoL among physically inactive adults recovering from COVID-19. These findings highlight the potential of AQ as an effective and feasible approach for post-COVID rehabilitation.