Fig. 1

Cardiovascular hemodynamic response determinants to autonomic challenge test in the study population. Maximum increase in blood pressure (max ΔBP) and maximum increase in heart rate (max ΔHR) measured during the 10-min NASA lean test from supine position in the study participants. Panel (A) represents the maximum values for SBP/DBP and HR in ME/CFS patients, (B) maximum values for long COVID patients, and (C) maximum values for healthy sedentary controls. Each dot denotes a single participant and the horizontal lines represent the mean values for each hemodynamic parameter. Shaded bars indicate postural orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS) in each study cohort, as defined in the Methods section