Resting heart rate is a predictor of mortality, but it would be better used as a marker of overall well-being, rather than a specific marker of cardiovascular health.
Heart rate is a marker of cardiovascular performance. The amount of beats yielded in a resting condition (resting heart rate, RHR) may be an indicator of myocardium efficiency since it represents the ability of the heart to provide the necessary supplies (e.g., nutrients, oxygen) for a certain demand. Therefore, RHR can be considered not only a predictor of physical fitness, but may also predict the risk of mortality.
American researchers investigated the prediction power of RHR on cardiovascular (CVD) and noncardiovascular mortality based on a population-based survey. Authors analyzed data from 6743 people who participated in the Third National Health and Nutrition Examination Survey (NHANES-III). A 12-lead electrocardiogram (ECG) was used as a screening index. Demographics (e.g., age, gender, race/ethnicity), laboratory parameters (e.g., fasting plasma glucose, total serum cholesterol levels), medical history (e.g., diabetes, previous CVD, cancer, thyroid disease, history of chronic obstructive pulmonary disease, smoking), physical examination (e.g., body mass index, blood pressure), and medication history were measured. RHR was measured by a 12-lead ECG. CVD mortality was defined by codes 100-178 in the International Classification of Diseases. All-cause mortality was considered the cause of death for those who CVD was not the primary death cause.
A higher RHR was associated with both CVD mortality and noncardiovascular mortality. Alterations in autonomic tone, heightened metabolic activity, and increased systemic inflammation may explain this association. It could be argued that an elevated RHR reflects an underlying imbalance in autonomic tone. Therefore, a higher RHR would be a common final pathway of systemic conditions related to inflammatory, metabolic, and neurology processes, such as myocardial infarction, sepsis, active autoimmune disease, sedentary behavior, and psychological stress. Higher myocardial oxygen consumption could also contribute to this association. Some study limitations include the source used to determine the mortality cause (i.e., National Death Index), the lack of controlling for important variables related to the participants’ health behaviors (e.g. exercise) that could influence both RHR and mortality. Therefore, confounding factors may have a bidirectional effect on results.
It can be concluded that RHR is a predictor of both CVD mortality and all-cause mortality. However, RHR should be considered a marker of overall well-being, rather than a specific marker of CVD health.
Written By: Vagner Raso