Abstract 10292: Longitudinal Changes in Cardiorespiratory Fitness and Measures of Adiposity are Associated With Heart Rate Variability: The Coronary Artery Risk Development in Young Adults (CARDIA) Study
Background: Physical activity and weight are associated with heart rate variability (HRV) in cross-sectional studies. However, it is less clear whether longitudinal changes in more accurate measures of cardiorespiratory fitness (graded exercise test duration [GXT]) and adiposity (body mass index [BMI] and waist circumference [WC]) are associated with HRV. We assessed these associations in a longitudinal analysis of CARDIA, a biracial observational cohort study.
METHODS: We included 2,402 subjects (mean age 45.3 ± 3.6 years, 58% female, 43% black) with HRV measured in 2005-06 (Year 20), and GXT and measures of adiposity obtained in 1985-86 (baseline, ages 18-30 years) and 2005-06. Measures of HRV (standard deviation of all normal RR intervals [SDNN], root mean square of successive differences [rMSSD]) were obtained from resting 30-second 12-lead ECGs. Longitudinal changes in GXT and adiposity was categorized as ≥10% increase, <10% change, or ≥10% decrease. We used multiple linear regression to assess associations of longitudinal changes in GXT and measures of adiposity with HRV.
RESULTS: The medians (IQR) of SDNN and rMSSD were 26.5 ms (17.4-40.8 ms) and 27.6 ms (17.8-41.9 ms), respectively. Longitudinal decrease in GXT was significantly associated with lower HRV after adjusting for measures of adiposity and other confounders. Longitudinal increases in BMI and WC were significantly associated with lower HRV. However, after additional adjustment for GXT, longitudinal increase in BMI was no longer associated with HRV (Table).
Conclusions: Although longitudinal changes in cardiorespiratory fitness and measures of adiposity were both associated with HRV in this middle-aged cohort, the association of longitudinal change in cardiorespiratory fitness with HRV was stronger. Further studies to determine the differential effects of improved cardiorespiratory fitness vs. weight loss on HRV are warranted.
- Heart rate/Heart rate variability
- Physical activity
- Cardiorespiratory fitness
- Longitudinal studies
- © 2013 by American Heart Association, Inc.