Peripheral Vascular Resistance Impairment during Isometric Physical Exercise in Normotensive Offspring of Hypertensive Parents

Background: A family history of hypertension is associated with vascular and autonomic abnormalities, as well as an impaired neurohemodynamic response to exercise. Objective: To test the hypothesis that normotensive individuals with a family history of hypertension present an impaired peripheral vascular resistance response to exercise. Methods: The study included 37 normotensive volunteers of both sexes who were sedentary, eutrophic, and nonsmokers, comprising 23 with (FH+; 24 +/- 3 years) and 14 without (FH-; 27 +/- 5 years) a family history of hypertension. Blood pressure, heart rate (DIXTAL (R)), forearm blood flow (Hokanson (R)), and peripheral vascular resistance were simultaneously measured for 3 minutes during rest and, subsequently, for 3 minutes during an isometric exercise at 30% of maximal voluntary contraction (Jamar (R)). Results: At rest, the FH+ and FH-groups present similar mean blood pressure (83 +/- 7 versus 83 +/- 5 mmHg, p = 0.96), heart rate (69 +/- 8 bpm versus 66 +/- 7 bpm, p = 0.18), forearm blood flow (3 +/- 1 mL/min/100 mL versus 2.7 +/- 1 mL/min/100 mL, p = 0.16), and peripheral vascular resistance (30 +/- 9 units versus 34 +/- 9 units, p = 0.21), respectively. Both groups showed a significant and similar increase in mean blood pressure (Delta = 15 +/- 7 mmHg versus 14 +/- 7 mmHg, p = 0.86), heart rate (Delta = 12 +/- 8 bpm versus 13 +/- 7 bpm, p = 0.86), and forearm blood flow (Delta = 0.8 +/- 1.2 mL/ min/100mL versus 1.4 +/- 1.1 mL/min/100 mL, p = 0.25), respectively, during exercise. However, individuals in the FH+ group showed no reduction in peripheral vascular resistance during exercise, which was observed in the FH-group (Delta = -0.4 +/- 8.6 units versus -7.2 +/- 6.3 units, p = 0.03). Conclusion: Normotensive individuals with a family history of hypertension present an impaired peripheral vascular resistance response to exercise.