The antihypertensive effects of aerobic versus isometric handgrip resistance exercise

Background: Aerobic exercise reduces blood pressure (BP) on average 5-7 mmHg among those with hypertension; limited evidence suggests similar or even greater BP benefits may result from isometric handgrip (IHG) resistance exercise. Method: We conducted a randomized controlled trial investigating the antihypertensive effects of an acute bout of aerobic compared with IHG exercise in the same individuals. Middle-aged adults (n = 27) with prehypertension and obesity randomly completed three experiments: aerobic (60% peak oxygen uptake, 30 min); IHG (30% maximum voluntary contraction, 4 x 2 min bilateral); and nonexercise control. Study participants were assessed for carotid-femoral pulse wave velocity pre and post exercise, and left the laboratory wearing an ambulatory BP monitor. Results: SBP and DBP were lower after aerobic versus IHG (4.8 +/- 1.8/3.1 +/- 1.3 mmHg, P = 0.01/0.04) and control (5.6 +/- 1.8/3.6 +/- 1.3 mmHg, P = 0.02/0.04) over the awake hours, with no difference between IHG versus control (P = 0.80/0.83). Pulse wave velocity changes following acute exercise did not differ by modality (aerobic increased 0.01 +/- 0.21 ms, IHG decreased 0.06 +/- 0.15 ms, control increased 0.25 +/- 0.17 ms, P>0.05). A subset of participants then completed either 8 weeks of aerobic or IHG training. Awake SBP was lower after versus before aerobic training (7.6 +/- 3.1 mmHg, P = 0.02), whereas sleep DBP was higher after IHG training (7.7 +/- 2.3 mmHg, P = 0.02). Conclusion: Our findings did not support IHG as antihypertensive therapy but that aerobic exercise should continue to be recommended as the primary exercise modality for its immediate and sustained BP benefits.