Exercise elicits orthostatic tachycardia and diastolic hypertension.

(A) Prior to first exercise, all participants had equivalent ΔHR. Three hours after the first stress test, 10 GWI subjects met the criteria for orthostatic tachycardia (START phenotype; P = 0.037, Fisher's test). START (n = 10; magenta triangles) subjects compared to controls (n = 10; cyan circles) and STOPP (n = 18; yellow squares) continued to have higher ΔHR recordings at 8, 16, 24 and 29 hours after first exercise. (B) START had significant increase ΔDBP at 8 and 16 hours after the first stress test. (C) Exercise did not cause ΔSBP in any of the subgroups. Δ = postural change. SBP = systolic blood pressure DBP = diastolic blood pressure HR = heart rate. Black and red arrows are start of first and second stress test respectively.*P<0.001; Error bars are means ±95% C.I.