Leg Muscle Preactivation and Tensing Mitigate initial Orthostatic Hypotension

A Canadian study demonstrated that preactivating lower body muscle (PREACT) and leg crossing with muscle tensing (TENSE) after standing attenuates symptoms and blood pressure (BP) drop of initial orthostatic hypotension (IOH) upon standing. The study included 24 female IOH participants (mean ± SD: 32 ± 8 years) completed 3 sit-to-stand maneuvers, including a stand with no intervention (Control), PREACT (through repeated knee raises for 30 seconds immediately before standing), and TENSE. The drops in mean arterial pressure (MAP) following PREACT (–21 ± 8 mm Hg) and TENSE (–18 ± 10 mm Hg) were significantly reduced compared to Control (–28 ± 10 mm Hg). The increase in cardiac output was significantly larger following PREACT (2.6 ± 1 L/min) but not TENSE (1.9 ± 1 L/min) compared to Control (1.4 ± 1 L/min). The Vanderbilt Orthostatic Symptom Score following PREACT (9 ± 8 au) and TENSE (8 ± 8 au) both were significantly reduced compared to Control (14 ± 9 au). The reduced drop in MAP following PREACT was a result of an overall increase in cardiac output, which started during the intervention while seated and continued through the stand. The TENSE intervention attenuated the drop in MAP by increasing stroke volume through mechanical compression of the leg vasculature after standing. Source: https://www.heartrhythmjournal.com/