The effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of controlled intervention studies
PubMed 33866630 · doi:10.1113/EP089424
What was done
Four databases were searched through September 2020 for studies assessing the effects of heat therapy (30–90 minutes per session across 10–36 sessions) compared to control conditions on blood pressure and vascular function in healthy and clinical populations. Fifteen studies were included in the systematic review and meta-analysis, and evidence certainty was evaluated using GRADE.
What was found
Compared with control conditions, heat therapy significantly decreased: - Mean arterial pressure: MD -5.86 mmHg (95% CI: -8.63 to -3.10; P < 0.0001; n = 4 studies) - Systolic blood pressure: MD -3.94 mmHg (95% CI: -7.22 to -0.67; P = 0.02; n = 10 studies) - Diastolic blood pressure: MD -3.88 mmHg (95% CI: -6.13 to -1.63; P = 0.0007; n = 9 studies) It significantly increased brachial artery flow-mediated dilatation (MD: 1.95%, 95% CI: 0.14 to 3.76; P = 0.03; n = 5 studies). Resting heart rate was unchanged (MD: -1.25 beats/min, 95% CI: -3.20 to 0.70; P = 0.21; n = 10 studies). Evidence certainty was rated moderate for systolic blood pressure, diastolic blood pressure, and heart rate, and low for mean arterial pressure and flow-mediated dilatation.
Why it matters
Repeated heat therapy demonstrates modest but statistically significant reductions in blood pressure and improvements in macrovascular endothelial function, supporting its potential utility as an adjunct cardiovascular health strategy.
Limits
The meta-analysis is based on a small total number of studies (15 included, with only 4–10 studies per outcome). Individual participant sample size is not reported in the abstract. Populations were heterogeneous, pooling healthy participants with clinical cohorts, and heat protocols varied substantially in exposure time and number of sessions.
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