Abstract 469: Relationship of Heart Rate and Physical Activity with Cardiovascular Risk Factors in a Multi-ethnic Population.

Abstract

Introduction: Resting heart rate (RHR) has been identified as an independent risk factor for cardiovascular disease and mortality. Hypothesis: Physical activity and RHR are associated with hypertension, dyslipidemia and insulin resistance in a multiethnic population. Methods: Cross-sectional data from 1,440 participants of Native Hawaiian, Japanese, Filipino, Caucasian, and mixed ethnic ancestries were examined. Body fat was estimated using body mass indices (BMI); fat distribution by waist-hip ratios (WHR); and insulin resistance using the Homeostasis Model (HOMA-IR). Total cholesterol, triglycerides, and HDL-cholesterol levels were assayed from fasting plasma samples. LDL cholesterol was calculated using the Friedewald formula. Blood pressure measurements and medical histories were obtained to determine hypertension status. Leisure time physical activity (PA) was estimated by calculating metabolic equivalents (METS) using the Modifiable Activity Questionnaire. Associations were estimated using logistic regression for dichotomous outcomes (HTN) and general linear models (GLM) for continuous variables. Results: Caucasians had lower prevalence of HBP and insulin resistance than all other ethnic groups; there were no statistically significant differences between other ethnic groups on mean RHR. HOMA-IR, RHR, BMI and WHR all differed significantly by ethnic group. Low RHR and high levels of physical activity were inversely associated with insulin resistance. After adjusting for covariates, only RHR remained significantly associated with HBP prevalence. Likewise, only RHR was significantly associated with total cholesterol, LDL and triglycerides. In contrast, HDL cholesterol was positively associated with physical activity but not associated with RHR. Conclusion: The relationship of RHR and PA is complex with RHR and PA actions differing for different CVD risk factors. Since low RHR may be an indicator of cardiovascular fitness, these findings suggest fitness, rather than energy expenditure, may be important in preventing most CVD risk factors, while activity level may be more important for increasing HDL levels. A customized approach to activity plans may need to consider specific patient risk profiles.