Background: There have been several cross-sectional studies reporting that delayed heart rate recovery (HRR) after exercise is associated with the development of the metabolic syndrome (MetS). However, there have been few longitudinal studies. We evaluated the longitudinal association of delayed HRR following a graded exercise treadmill test (GTX) with the incident MetS including metabolic parameters as adjusting factors.
Methods: A retrospective longitudinal cohort study of participants without MetS, diabetes or cardiovascular diseases has been designed. HRR was calculated as peak heart rate minus heart rate after a 1-minute rest (HRR 1), heart rate after a 2-minute rest (HRR 2), and heart rate after a 3-minute rest (HRR 3). To investigate the association between HRR and incident MetS, multivariate Cox proportional hazards analysis was performed.
Results: During 9,683 person-years of follow-up between 2006 and 2012, there were 676 (31.2%) incident cases of the MetS. After adjustment for age, sex, smoking status, baseline heart rate, peak heart rate, peak oxygen uptake, hs-CRP, waist circumference, systolic blood pressure, TG, LDL-C, HDL-C, fasting plasma glucose, HOMA-IR, and HbA1c, the hazard ratios (HR) [95% confidence interval (CI)] of incident MetS comparing the first and second tertiles to the third tertile of HRR 3 were 1.492 (1.146-1.943) and 1.277 (1.004-1.624) (P for trend = 0.003). As a continuous variable, after full adjustments, the HR (95% CI) of incident MetS associated with each 1-second decrease in HRR3 was 1.015 (1.005 -1.026) (P = 0.004).
Conclusion: Delayed HRR 3 after exercise could predict incident MetS, even after adjusting for metabolic parameters. However, HRR 1 and HRR 2 have not shown the statistic significance.
T. Yu: None. S. Jin: None. K. Hur: None. J. Bae: None. J. Jee: None. J. Kim: None. M. Lee: None.