Few reports have been published on the epidemiology of heart rate in general populations including women and blacks. In the first cycle of the National Health Examination Survey, resting heart rate was significantly higher in women than in men at each age in both races. Age and race were inconsistently related to heart rate, black men having slightly lower rates than white men at ages 18 to 34. The product of heart rate and mean blood pressure was consistently highest in black women. Heart rate was associated with obesity, waist girth, and waist-to-hip girth ratio in men under 55 years and with blood pressure and post-load serum glucose in all groups. Sex differences at each age were larger (6 to 14 beats/min) when adjusted for multiple variables. Multivariate linear regression analysis confirmed the independent associations of heart rate with blood pressure and serum glucose. After controlling for other risk factors, prevalent hypertensive subjects had higher heart rates than normotensive individuals in all groups. Further research is needed to elucidate mechanisms of the associations of resting heart rate with sex, risk factors, coronary heart disease, and mortality.