cardiac autonomic modulationepidemiologyethnicitylongitudinal trajectorynormative agingsocioeconomic status

No study to date has investigated longitudinal trajectories of cardiac autonomic modulation changes with aging; therefore, we lack evidence showing whether these changes occur naturally or are secondary to disease or medication use. This study tested whether heart rate variability (HRV) trajectories from middle to older age are largely normative or caused by pathological changes with aging in a large prospective cohort. We further assessed whether HRV changes were modified by socioeconomic status, ethnicity, or habitual physical activity. This study involved 3176 men and 1238 women initially aged 44 to 69 years (1997-1999) from the UK Whitehall II population?based cohort. We evaluated time? and frequency?domain HRV measures of short?term recordings at 3 time points over a 10?year period. Random mixed models with time?varying covariates were applied. Cross?sectionally, HRV measures were lower for men than for women, for participants with cardiometabolic conditions, and for participants reporting