Increased resting heart rate (HR) is a known risk factor for cardiovascular morbidity and mortality (1–3), including stroke (4) and sudden cardiac death (5,6). Heart rate increased by 20 beats per minute (BPM) is associated with 30-50% higher mortality and appears to be independent of confounder factors (7). High HR increases myocardial oxygen consumption yet lessens oxygen delivery to myocardial tissue. It also increases arterial stiffness and risk of plaque rupture (8). Although HR can be influenced by many non-genetic factors (e.g. exercise, smoking and cardiovascular drugs), the heritability of resting HR is estimated to be 26–32% from family studies (9,10), and 55–63% from twin studies (11).
