Why is this study important?
It is estimated that more than 1.4 billion of the world’s population have high blood pressure (hypertension), which is a leading cause of illness and death. Medications commonly prescribed to treat high blood pressure carry a number of substantial limitations, including negative side effects, considerable financial costs, and poor adherence rates. As such, alternative non-pharmacological approaches , such as exercise training, are largely favoured .
Based on previous research, traditional aerobic exercise training consisting of 150 minutes of at least moderate-intensity continuous exercise performed over the course of a week remains the primarily recommended approach for blood pressure control.
However, these recommendations are largely based on historical data, and recent research has provided evidence to show that new modes of exercise, such as high-intensity interval training and isometric (static) exercise training , can provide greater improvements in blood pressure control. As a consequence, the optimal exercise intervention for the management of resting blood pressure is unknown, which will impact exercise recommendations at the population level.
How was the study?
We conducted a comprehensive systematic search of all randomized controlled trials that reported changes in systolic (SBP) and/or diastolic blood pressure (DBP) after an exercise intervention ≥2 weeks with an eligible control group without intervention.
The training protocols were divided into the following main categories of exercise modes for comparison: aerobic exercise training, dynamic resistance training, combined training (aerobic with dynamic resistance), high-intensity interval training, and isometric exercise training .
Each category was then further explored for subgroups, allowing secondary analysis of walking, running, cycling, sprint interval training, aerobic interval training, isometric handgrip exercise training, leg extension isometric and isometric squat against the wall .
Independent pairwise analyzes were performed on all primary and secondary exercise modes. Each pairwise primary analysis was subsequently analyzed by baseline blood pressure. Separately, to facilitate comparison of exercise modes that have not been directly compared in head-to-head randomized controlled trials, all modes were analyzed collectively in Bayesian network meta-analyses. Additional moderator and sensitivity analyzes were also performed during the analysis.
What did the study find?
270 randomized controlled trials were included in the final analysis, with a pooled sample size of 15,827 participants. Pairwise analyzes demonstrated significant reductions in resting systolic blood pressure (sBP) and diastolic blood pressure (dBP) after aerobic exercise training (-4.49/-2.53mmHg, P-0.001), dynamic resistance training (-4.55/-3.04mmHg, P-0.001), combined training (-6.04/-2.54mmHg, P-0.001), high-intensity interval training (4.08/-2.50mmHg, P-0.001) and isometric exercise training (-8.24/-4.00mmHg, P-0.001).
The order of effectiveness of the network meta-analyses according to the area under the cumulative classification curve (SUCRA) for SBP values were isometric exercise training (SUCRA: 98.3%), combined training (75.7%), dynamic resistance training (46.1%), aerobic exercise training (40.5%) and high-intensity interval training (39.4%).
Secondary network meta-analyses revealed isometric wall squatting and running as the most effective submodes in reducing SBP (90.4%) and dBP (91.3%) respectively.
What are the key points for practice?
Aerobic exercise training, dynamic resistance training, combined training, high-intensity interval training, and isometric exercise training are significantly effective in reducing sBP and dBP at rest.
However, isometric exercise training is the most effective way. The types of isometric exercises discussed in this work include a wall sit, grip squeeze, or leg extension, often performed in 3 sessions per week consisting of 4 x 2 minute intervals, separated with 2 minute rest periods in between. each set.
These findings provide a comprehensive data-driven framework to support the development of new exercise guidelines for the prevention and treatment of high blood pressure.
