Acute blood pressure responses to plank and wall sit isometric exercise in adults

Isometric exercise is an accessible, time efficient intervention for reducing blood pressure (BP). However, guideline recommendations for its use remain sparse due to safety concerns. This study aimed to determine the proportion of participants whose BP exceeded predefined limits during isometric exercise. Secondary aims were to examine differences in BP responses between sexes and across exercises.

Participants attended the laboratory for two sessions: screening and familiarisation, and exercise testing. In session two, participants performed the plank and wall sit in a randomised order while their BP was continuously monitored noninvasively using the Finapres NOVA. Each exercise was performed until volitional fatigue or until reaching the American College of Sports Medicine limits of SBP (>250 mmHg) or DBP (>115 mmHg).

Sixty-two apparently healthy participants completed the study (age 26.7 ± 8.2 years, 52% women, resting BP 121 ± 8/77 ± 6 mmHg). Almost all participants were stopped [plank: 97% (95% confidence interval, 95% CI 89-99); wall sit: 98% (95% CI 91-100)] due to DBP more than 115 mmHg after an average of approximately 50 s of exercise. All women exceeded the DBP limit [plank: 100% (95% CI 89-100); wall sit: 100% (95% CI 89-100)] compared to most males [plank: 93% (95% CI 78-99); wall sit: 97% (95% CI 83-99)]. No participants reached the SBP limit. No adverse events were reported.

Common isometric exercises cause a marked increase in BP, particularly DBP. Despite this, no adverse events occurred. Future studies should examine the dose-response of different isometric exercises in higher risk populations to better inform its clinical suitability.