Characterizing the Blood Pressure Response to Physical Counterpressure Manoeuvres Using Surface Electromyography in Adults With Long Covid

Orthostatic intolerance (OI) is common in Long Covid. Physical counterpressure manoeuvres (PCM) may improve OI other disorders. We characterised the blood pressure-rising effect of PCM using surface electromyography (sEMG) and investigated its association with fatigue adults Participants performed an active stand beat-to-beat hemodynamic monitoring sEMG both thighs, including at 3-minutes post-stand. Multivariable linear regression between change systolic pressure (SBP) normalised root mean square (RMS) amplitude, controlling for confounders Chalder Fatigue Scale (CFQ). In 90 participants (mean age 46), SBP rise was 13.7 (SD 9.0) mmHg. regression, significantly, directly associated RMS ( $\beta =0.25$ , 95% CI 0.07–0.43, P = 0.007); however, CFQ not significant. measured by augmented without influence fatigue.