Cardiovascular response to static contraction in borderline hypertension.

Nine young males with borderline hypertension (BH) (mean age +/- SD, 25 +/- 5 yr) and 13 young male normotensive controls (NT) (24 +/- 3 yr) were studied to determine their cardiovascular responses to small and large muscle static contractions. The subjects performed one-arm handgrip and two-leg extension in a randomly assigned order for 3 min at 30% of maximal voluntary contraction. Mean intra-arterial blood pressure (MABP), heart rate (HR), and tension were measured throughout the contractions. Borderline hypertensive patients had a higher MABP at rest (p less than 0.005) and at the end of both types of static contractions (p less than 0.05). The average increases in MABP from rest to the end of exercise (delta MABP) were slightly greater for the BH patients (6 mmHg), but these differences were not significant (p greater than 0.1). However, a greater percentage of BH patients were hyperreactive to handgrip (delta BP greater than 35 mmHg) and leg extension (delta BP greater than 40 mmHg) when compared to controls. These data indicate that, in general, young men with borderline hypertension demonstrate normal cardiovascular regulation in response to static contraction, but that a portion of this population may be hyperreactive to this type of circulatory stress.