Continuous variables are presented as mean ± SD or median [IQR]. Categorical variables are presented as n (%).

HCM, hypertrophic cardiomyopathy; $ppV˙O2$⁠, per cent predicted peak oxygen consumption; CD, implantable cardioverter-defibrillator.

^aCompetitive athlete defined as one that regularly participates in organized competitions. Team athlete defined as one that competes as part of an organized team. Recreational athlete defined as one that regularly trains intensely with personal goals but does not compete against others. Endurance athlete defined as one that predominantly participates in endurance sports (i.e. running, cycling, rowing, swimming, and triathlon). Mixed sport athlete defined as one that participates in a mixture of sports, including endurance, team, lifting, and/or is regularly and intensely active as part of occupation (i.e. armed services or personal trainer). Physically active individuals defined as meeting at least guideline-recommended minimum recommended ‘aerobic’ activity levels (>150 min/week of moderate and/or >75 min/week of intense ‘aerobic’ physical activity).

^bHCM participants had maximal WT of ≥15 mm with the exception of n = 2 individuals with 13–14 mm maximal WT in the setting of a documented family history of HCM. Maximal WT was derived from cardiac magnetic resonance imaging (CMR) in 25 participants and transthoracic echocardiography in 5 participants who did not have CMR data available (e.g. severe claustrophobia, low quality CMR, no recent CMR since ICD placement and outside CMR without available images).