This study examined the relationship between changes in physical activity and their impact on exercise capacity and health-related quality of life over a 3-year span in patients with CHD.

We evaluated 99 young patients with CHD, aged 13–18 years at the outset. Physical activity, health-related quality of life, and exercise capacity were assessed via questionnaires and peak oxygen uptake measurements at baseline and after 3 years; changes in measures were estimated between the two time points and categorised into quartiles. Participants were stratified according to achieved (active) or not-achieved (inactive) recommended levels of physical activity (≥150 minutes/week) at both time points.

Despite increases in physical activity, exercise capacity, and health-related quality of life over 3 years, the changes were not statistically significant (all p > 0.05). However, a positive association was found between physical activity changes and exercise capacity (ß = 0.250, p = 0.040) and health-related quality of life improvements (ß = 0.380, p < 0.001). Those with the most pronounced physical activity increase showed notable exercise capacity (p < 0.001) and health-related quality of life increases (p < 0.001) compared with patients with the largest decline in physical activity. The active-inactive category demonstrated a notable decline in exercise capacity compared to the active-active group, while the inactive-active group showed health-related quality of life improvements.

Over 3 years, increased physical activity was consistently linked to increases in exercise capacity and health-related quality of life in patients with CHD, highlighting the potential of physical activity augmentation as an intervention strategy.