Abstract 18626: Quadratic Regression Reveals an Accelerated Age-related Decline of Maximal Heart Rate in those with Low and Moderate Cardiorespiratory Fitness
Background: Maximal heart rate (HRmax) obtained from an exercise test provides important prognostic information (chronotropic incompetence). Interpretation of HRmax has typically been derived from age-predicted linear regression equations, such as 220-age with large standard error of estimates of ~ ± 10-12 bpm. Recent investigations, with quadratic regression analyses, suggest a more rapid decline in HRmax may occur in older adults. However, a limitation in those studies was a lack of an objective indicator of maximal exercise test effort and consideration of cardiorespiratory fitness (CRF) as a potential influence of this age-related change.
Methods: Cardiopulmonary treadmill exercise tests (respiratory exchange ratio ≥1.0 and measured VO2max) from participants (1161 men, 1070 women; not using HR altering medications) of a university based health-assessment/fitness program were studied. Individuals were categorized into CRF categories (high [A], moderate [B], and low [C]) relative to age and gender normative VO2max classifications. Quadratic regression analyses were compared to linear equations to assess the age-related decline in HRmax by CRF category.
Results: There was little improvement in R2 (<1%) with the quadratic analyses for any of the CRF categories. However, as shown in the figure, the quadratic analyses revealed the HRmax decline with age is accelerated beginning at ~ 60 years in low and moderate CRF groups.
Conclusion: These findings demonstrate HRmax is blunted in older individuals with low and moderate CRF. This suggests a possibility of greater likelihood of chronotropic incompetence, which should be explored in future studies.
Author Disclosures: M. Tuttle: None. C. Ozemek: None. M. Whaley: None. H. Finch: None. L. Kaminsky: None.
- © 2014 by American Heart Association, Inc.