Abstract P127: Gender and Fitness Status Influence Age-related Decline in Peak Heart Rate Achievement: Insight From the FIT Cohort

Abstract

Background: The declines in peak heart rate (HR) and fitness level with age are related; however, whether this association differs based on gender is not well appreciated. In a large cross-sectional cohort of women and men referred for a clinically indicated exercise treadmill test (ETT), we set out to determine whether the decrease in peak HR by age varied by gender (and fitness) in the Henry Ford Exercise Testing (FIT) project. Methods: We analyzed data on 38,196 apparently-healthy patients aged 18-96 [mean age 51 ± 12 yrs, 25% black, 48% women] who completed an ETT. Those with history of coronary heart disease, congestive heart failure, diabetes on medications, atrial fibrillation or flutter, or taking AV nodal blocking medications were excluded. Being “fit” was defined as achieving ≥ the median MET level for each sex/age-decile group. Peak HR vs age was plotted, and regression lines were used to determine the intercept and slope for each group. Results: Men had higher peak HR than women but with a greater decline over time; the respective intercepts and slopes for peak HR estimates were 202.9 and 0.90 for men and 197.3 and 0.80 for women, (p-interaction = 0.023). Fit people also started out with higher peak HR but approached unfit people at higher age groups; respective intercept and slope by fitness status were 203.0 and 0.87 for fit and 194.7 and 0.83 for unfit (p-interaction <0.001). Separate regression lines were generated for categories of fit men/unfit men, fit women/unfit women ( Figure ). Fit and unfit men had similar declines in peak HR with increasing age (slope=0.92); whereas fit women (slope=0.81) had a slightly greater decline in peak HR with increasing age than unfit women (slope=0.73). However, peak absolute HR for fit people still remains higher than for unfit people even into elderly ages. Conclusion: In this cross-sectional cohort of patients referred for a clinical ETT, we found that the age-related decline in peak HR is influenced by both gender and fitness status.