The findings support the development of new exercise guidelines for blood pressure control, the authors said.
Previous research, based on older data that excluded high-intensity interval training (HIIT) and isometric exercise training (IET), led to aerobic exercise training (AET) being recommended for managing blood pressure, according to the authors.
Although AET, HIIT, dynamic resistance training (RT), and combined training (CT) are also effective in reducing both systolic and diastolic blood pressure, the new analysis suggests that IET does it best.
The analysis showed reductions in blood pressure of 8.24/4 mm Hg after IET, compared with 4.49/2.53 mm Hg after AET; 4.55/3.04 mm Hg after RT; 6.04/2.54 mm Hg after CT; and 4.08/2.50 mm Hg after HIIT.
“These findings mirror our smaller-scale trials, and therefore we anticipated that isometrics would be largely effective,” Jamie O’Driscoll, PhD, of Canterbury (England) Christ Church University, said in an interview. However, “the magnitude of difference between isometrics and some other modes was surprising.”
The study was published online in the British Journal of Sports Medicine.
All modes effective
The investigators analyzed data from 270 randomized controlled trials including 15,827 people published between 1990 and February 2023. For consistency, the protocol/intensity of each included paper was screened against the Exercise Prescription in Everyday Practice and Rehabilitative Training tool to be defined and categorized.
All protocols were then stratified as AET, RT, CT, HIIT or IET.
As appropriate, protocols were then further stratified into subgroups: AET included walking, running, and cycling; HIIT included sprint interval training and aerobic interval training; and IET included isometric leg extension and isometric wall squat.
Healthy resting blood pressure was defined as a reading below 130/85 mm Hg, prehypertension as 130-139/85-89 mm Hg, and hypertension as 140/90 mm Hg or higher.
All exercise modes led to statistically significant reductions in systolic BP in normal blood pressure cohorts; however, all reductions were substantially larger in individuals with hypertension.
Pairwise analyses showed significant reductions in resting systolic BP and diastolic BP following AET (−4.49/–2.53 mm Hg); RT (–4.55/–3.04 mm Hg), CT (–6.04/–2.54 mm Hg), HIT (–4.08/–2.50 mm Hg); and IET (–8.24/–4.00 mm Hg).
In the network meta-analysis, the rank order of effectiveness for systolic BP based on surface under the cumulative ranking curve values were IET (SUCRA: 98.3%), CT (75.7%), RT (46.1%), AET (40.5%), and HIIT (39.4%).
Secondary network meta-analyses showed that isometric wall squat was the most effective submode for reducing systolic BP (90.4%), followed by isometric leg extension, isometric hand grip, cycling, running, CT, sprint interval training, other aerobic, RT, aerobic interval training, and walking.
Running was the most effective submode for lowering diastolic BP (91.3%), followed by isometric wall squat, isometric handgrip, isometric leg extension, cycling, sprint interval training, RT, AIT, other aerobic, CT, and walking.
The authors acknowledged limitations, including variability in exercise interventions, missing data, variable quality of exercise monitoring and analyses, lack of blinding to group allocation, varying participant populations, and publication bias.
Nevertheless, they concluded, “the results of this analysis should inform future exercise guideline recommendations for the prevention and treatment of arterial hypertension.”