Acute effects of isometric plank exercise on 24-hour ambulatory blood pressure in young adults with prehypertension: a randomized cross-over trial

Background: Isometric resistance exercise has been shown to reduce blood pressure (BP), particularly when involving large muscle groups. Isometric plank exercise (IPE), which elicits extensive muscle activation, may offer similar benefits; however, its acute effects on ambulatory blood pressure monitoring (ABPM) and variability remain unclear. This study aimed to examine the acute effects of IPE on ABPM, blood pressure variability (BPV) and ambulatory arterial stiffness index (AASI) in young adults with prehypertension. Methods: Twelve young adults (mean age, 26.4 ± 5.4 years) with prehypertension (systolic BP [SBP] 120–139 mmHg or diastolic BP [DBP] 80–89 mmHg) participated in a randomized cross-over trial. Each participant completed 2 sessions in random order: 1) 4 × 2-minute IPE session with 1-minute rest, and 2) a non-exercise control session. Office BP was measured at baseline, 30 minutes, and 90 minutes post-trial. ABPM, BPV and AASI were recorded over the following 24 hours. Results: A significant interaction effect was observed for systolic office BP (P = 0.009), with post-hoc analysis revealing a significant reduction at 90 minutes post-IPE session (P = 0.048). Twenty-four-hour average systolic and DBP were significantly lower in the IPE session compared to control session (P = 0.004, P = 0.031, respectively). In addition, both daytime SBP (P = 0.020) and nighttime DBP (P = 0.014) significantly decreased after the IPE session. Nighttime systolic BPV was also significantly decreased after the IPE session (P = 0.040). No significant changes were observed in other BPV index and AASI. Conclusions: IPE significantly reduced 24-hour SBP and DBP and improved nighttime BP variability in young adults with prehypertension. These findings provide preliminary evidence that IPE may serve as a potential nonpharmacologic strategy for early BP management. Large-scale interventional studies are warranted to confirm and extend on these effects.