Heart rate recovery after treadmill exercise testing is an independent predictor of stroke incidence in men with metabolic syndrome

Abstract

Heart rate recovery (HRR), a measure of the heart rate which decreases after a graded exercise test, has been associated with mortality and cardiovascular diseases. However, the association between HRR and risk of stroke has not been fully determined in men with metabolic syndrome (MetS). Participants were 3886 men with MetS, aged 40-79 years, who completed a maximal exercise test during 1979-2004. We calculated 5-min HRR as the primary predictor and identified HRR tertiles; tertile 1 (<59 bpm), tertile 2 (59-71 bpm), and tertile 3 (>71 bpm). Stroke incidence was ascertained from responses to mail-back surveys during 1982-2004. Differences in baseline characteristics across HRR tertiles were examined using general linear model. Hazard ratios (HRs) and 95% confidence intervals (95% CIs), were estimated using Cox regression model after adjusted for potential confounders. We identified 90 incident stroke cases during an average follow-up of 15.2 years. After adjusting for age-, examination year-, and survey response indicator, a significant inverse association between HRR and incident stroke was observed in men with MetS (p < 0.001). Compared with the lowest tertile of HRR, adjusted HRs in the second and third tertiles were 0.96 (0.53-1.74) and 0.41 (0.20-0.87), respectively. We also found a significant linear trend (p < 0.03) across increments of HRR. Delayed HRR was independently associated the higher risk of incident stroke in men with MetS. This suggests that HRR have prognostic value of stroke risk for men with MetS.