A reduced initial HR overshoot, along with a drop in CO, might suggest an impaired or decompensated initial phase in the CV pain-o-meter pattern, while a higher steady-state HR with a lower CO could indicate a similar impairment at a later stage, resembling postural orthostatic tachycardia syndrome (POTS), as seen in renin-dependent hypertension, chronic fatigue syndrome, and functional abdominal pain [8, 77, 78]. Here, REN is linked to myalgic encephalomeyelitis/chronic fatigue syndrome.