IMPORTANCE Time-updated heart rate (HR) and temporal change in HR (ΔHR) are associated with outcome in individuals with established heart failure (HF). Whether these factors are associated with outcomes in a community-based cohort is unclear. OBJECTIVE To determine whether the time-updated analysis of resting HR, defined as the most recent HR value measured before occurrence of an event or the end of study, and ΔHR over time are associated with outcomes in a community-based cohort. DESIGN, SETTING, AND PARTICIPANTS A total of 15 680 participantswere enrolled in the Atherosclerosis Risk in Communities cohort study, with HR recorded at baseline and during 3 follow-up visits from 1987 to 1998, with a median interval between visits of 3.0 (interquartile range, 2.9-4.0) years. The ΔHR was calculated by assessing a change in HR from the preceding visit. Participants were followed up until December 31, 2014, equating to 28 years of follow-up. The present study was conducted from March 2014 to June 2016 with updated analysis. MAIN OUTCOMES AND MEASURES Baseline HR, time-updated HR, and ΔHR associated with outcomes, adjusted for established baseline and time-updated risk factors and medications. The main outcomes measures included all-cause mortality, incident HF, incidentmyocardial infarction, stroke, and cardiovascular and noncardiovascular death. RESULTS Of the 15 680 participants, 8656 (55.2%) were women, mean (SD) age was 54 (6) years, and 4218 (26.9%) were African American. Time-updated HR and ΔHR were associated with death, incident HF, incidentmyocardial infarction, stroke, and cardiovascular and noncardiovascular death compared with baseline HR. For example, a ΔHR from the preceding visit was significantly associated with increased risk of all-cause mortality (adjusted hazard ratio, 1.12; 95%CI, 1.10-1.15; P < .001 for every 5-bpm increase in HR from the preceding visit) and time-updated HR was also significantly associated with increased risk of all-cause mortality (adjusted hazard ratio, 1.14; 95%CI, 1.12-1.17; P < .001 for every 5-bpm higher time-updated HR). CONCLUSIONS AND RELEVANCE In a community-based cohort, time-updated HR and ΔHR are associated with mortality and nonfatal outcomes of incident HF,myocardial infarction, and stroke.