Is Delayed Post-exercise Blood Pressure Recovery A Marker For Metabolic Syndrome In Young Men?

Abstract

Metabolic syndrome (MetS), an increasingly prevalent disorder, is denned by a cluster of cardio-metabolic risk factors including obesity, dyslipidemia, and hypertension. Autonomic dysfunction has been linked to chronic diseases arising from these risk factors. Following exercise, heart rate (HR) and blood pressure (BP) return to resting levels by parasympathetic activation and sympathetic withdrawal. Therefore, altered response patterns for these measures in post-exercise recovery have increasingly been accepted as markers of autonomic imbalance. MetS is associated with increased sympathetic activity, but little is known about the relationship between MetS and post-exercise autonomic balance, especially in young men. PURPOSE: To evaluate whether measures of autonomic balance, including post-exercise HR and BP recovery, are altered in young men with MetS. METHODS: Subjects included 8 young men (BMI: Mean ± SD = 33.4 ± 7.0 kg/m2; age = 21.6 ± 3.7 yr) with MetS and 9 without MetS (BMI = 21.9 ± 1.5 kg/m2; age = 22.0 ± 3.0 yr). The National Cholesterol Education Program standards (ATP III. Circulation, 2002) define MetS as having 3 or more of the following: elevated fasting blood glucose or triglycerides, pre-hypertension, abdominal obesity, or reduced HDL-C. Subjects performed a maximal effort cycle ergometer exercise test using a δ15W/ min ramping protocol. HR, systolic and diastolic blood pressure (SBP and DBP) and oxygen consumption (VO2) were recorded during exercise. Cardiovascular responses were evaluated at 15sec intervals during active recovery. RESULTS: Relative VO2pk, HR and SBP did not differ between groups at rest or at peak exercise. In recovery cardiovascular responses, only SBP was higher in the MetS group across minutes 1–5 min (p = 0.026). Similar assessments by Sung et al. (J Korean Med Sci, 2006) in older adults with MetS have shown delayed HR recovery following exercise, but not a delayed SBP response. CONCLUSIONS: Attenuated post-exercise BP recovery occurs in sedentary young men with MetS. Recovery responses provide useful information about autonomic balance and increase the clinical utility of the test.