Fig. 1.

Index of systemic total peripheral resistance during supine baseline, 3 different degrees of head-down tilt (HDT), and rapid transitions to 75° head-up tilt (HUT). BL, supine baseline; Con, HUT without previous HDT; HDT1, HDT values between 0 and 7 s; HDT2, HDT at 8–15 s. 75° HUT at the times 5: 0–5 s; 10: 6–10 s; 15: 11–15 s; 20: 16–20 s; 40: 21–40 s; 60: 41–60 s. Significantly different &vs. Control, *vs. −10° HDT condition, #vs. −25° at same period, P < 0.05. Data are expressed as means ± SD.