Association of metabolic syndrome with impaired heart rate recovery and low exercise capacity in young male adults

Abstract

Impaired heart rate recovery (HRR) is a powerful predictor of overall mortality. The aim of the present study is to assess HRR in young adult males with metabolic syndrome and to compare HRR with those of obese patients who do not meet the criteria for metabolic syndrome. Sixty-four newly diagnosed and untreated young male subjects (24 +/- 3 years) with metabolic syndrome and 40 age and sex matched obese or overweight control subjects (ages 23 +/- 3 years) were enrolled in the study. All subjects performed a symptom limited exercise stress test under the standard Bruce protocol. HRR was calculated in the first, second and third minutes of the recovery period. The relationship between metabolic syndrome and HRR was evaluated via logistic regression analysis and a P-value < 0.05 was accepted as significant. Body mass index (BMI) was 38.6 +/- 3.68 and 32.22 +/- 2.99 kg/m(2) in the study and control groups, respectively (P < 0.001). Total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, systolic and diastolic blood pressures and fasting glucose levels were significantly higher in the study group. HRR in the first minute of the recovery period and mean exercise capacity were significantly lower in the study-group patients with metabolic syndrome (P < 0.001 and P = 0.012, respectively). We determined that HRR was impaired in young adult males with metabolic syndrome compared with obese ones who do not meet the criteria of metabolic syndrome. This decreased HRR may have prognostic value in the prediction of vascular events in patients with metabolic syndrome.