The Metabolic Syndrome and the immediate antihypertensive effects of aerobic exercise: a randomized control design
BACKGROUND
The metabolic syndrome (Msyn) affects about 40% of those with hypertension. The Msyn and hypertension have a common pathophysiology. Exercise is recommended for their treatment, prevention and control. The influence of the Msyn on the antihypertensive effects of aerobic exercise is not known. We examined the influence of the Msyn on the blood pressure (BP) response following low (LIGHT, 40% peak oxygen consumption, VO2peak) and moderate (MODERATE, 60% VO2peak) intensity, aerobic exercise.


METHODS
Subjects were 46 men (44.3 +/- 1.3 yr) with pre- to Stage 1 hypertension (145.5 +/- 1.6/86.3 +/- 1.2 mmHg) and borderline dyslipidemia. Men with Msyn (n = 18) had higher fasting insulin, triglycerides and homeostasis model assessment (HOMA) and lower high density lipoprotein than men without Msyn (n = 28) (p < 0.01). Subjects consumed a standard meal and 2 hr later completed one of three randomized experiments separated by 48 hr. The experiments were a non-exercise control session of seated rest and two cycle bouts (LIGHT and MODERATE). BP, insulin and glucose were measured before, during and after the 40 min experiments. Subjects left the laboratory wearing an ambulatory BP monitor for the remainder of the day. Repeated measure ANCOVA tested if BP, insulin and glucose differed over time among experiments in men without and with the Msyn with HOMA as a covariate. Multivariable regression analyses examined associations among BP, insulin, glucose and the Msyn.


RESULTS
Systolic BP (SBP) was reduced 8 mmHg (p < 0.05) and diastolic BP (DBP) 5 mmHg (p = 0.052) after LIGHT compared to non-exercise control over 9 hr among men without versus with Msyn. BP was not different after MODERATE versus non-exercise control between Msyn groups (p > or = 0.05). The factors accounting for 17% of the SBP response after LIGHT were baseline SBP (beta = -0.351, r2 = 0.123, p = 0.020), Msyn (beta = 0.277, r2 = 0.077, p = 0.069), and HOMA (beta = -0.124, r2 = 0.015, p = 0.424). Msyn (r2 = 0.096, p = 0.036) was the only significant correlate of the DBP response after LIGHT.


CONCLUSION
Men without the Msyn respond more favorably to the antihypertensive effects of lower intensity, aerobic exercise than men with the Msyn. If future work confirms our findings, important new knowledge will be gained for the personalization of exercise prescriptions among those with hypertension and the Msyn.