Objectives Recommendations on physical activity (PA) for adults with hypertrophic cardiomyopathy (HCM) are not well established. We investigated the association of PA intensity with mortality in the general adult HCM population.

Methods A nationwide population-based cohort of individuals with HCM who underwent health check-ups including questionnaires on PA levels were identified from the years 2009 to 2016 in the National Health Insurance Service database. Subjects who reported no PA at baseline were excluded. To estimate each individual’s PA level, the PA score (PAS) was calculated based on the self-reported questionnaires, and the study population was categorised into three groups according to tertiles of PAS. The associations of PAS with all-cause and cardiovascular mortality were analysed.

Results A total of 7666 participants (mean age 59.5 years, 29.9% were women) were followed up for a mean 5.3±2.0 years. All-cause and cardiovascular mortality progressively decreased from the lowest to the highest tertiles of PA intensity: 9.1% (4.7%), 8.9% (3.8%) and 6.4% (2.7%), respectively (p-for-trend=0.0144 and 0.0023, respectively). Of note, compared with the middle PA group, the highest PA group did not have an increased risk of all-cause and cardiovascular mortality (HR 0.78, (95% CI 0.63 to 0.95) and HR 0.75 (95% CI 0.54 to 1.03), respectively). All subgroup and sensitivity analyses consistently showed that all-cause and cardiovascular mortality did not increase with higher PA levels.

Conclusions Moderate-to-vigorous-intensity PA, in a middle-aged population of patients with HCM, was associated with progressive reduction of all-cause and cardiovascular mortality. The impact of vigorous-intensity PA on a younger age group requires further investigation.