The antihypertensive effects of aerobic versus isometric handgrip resistance exercise

Abstract

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 × 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.

Fig. 1

Study Design. *Blood pressure measured throughout (see text for details). †Ambulatory blood pressure monitor worn afterwards until waking the next morning. ‡Pulse wave velocity measured throughout (see text for details). GEST, graded exercise stress test. MVC, maximum voluntary contraction. VO2peak, peak oxygen consumption

Fig. 2

Average awake systolic (A) and diastolic (B) blood pressure change from baseline at hourly intervals for 10 hours after control and exercise among 27 sedentary adults. *p<0.05 aerobic versus control. †p<0.05 aerobic versus isometric handgrip. Baseline values were control 121.7±2.4 / 79.7±1.5 mmHg, aerobic 121.4±2.0 / 79.7±1.4 mmHg, isometric handgrip 120.1±1.9 / 77.9±1.3 mmHg.

Fig. 3

Average awake systolic (A) and diastolic (B) blood pressure at hourly intervals before and after exercise training among participants assigned to the aerobic (n=6) and isometric handgrip (n=5) training groups. *p<0.05 versus pre-training. †p<0.05 change following aerobic exercise training versus change following isometric handgrip exercise training