Repetitive high-sustained gravitoinertial stress does not modulate pressure responsiveness to peripheral sympathetic stimulation

Purpose We evaluated the hypothesis that repetitive gravitoinertial stress would augment the arterial-pressure response to peripheral sympathetic stimulation. Methods Before and after a 5-weeks G-training regimen conducted in a human-use centrifuge, twenty healthy men performed a hand cold-pressor test, and nine of them also a foot cold-pressor test (4 min; 4 °C water). Arterial pressures and total peripheral resistance were monitored. Results The cold-induced elevation (P ≤ 0.002) in arterial pressures and total peripheral resistance did not vary between testing periods, either in the hand [mean arterial pressure: Before = + 16% vs. After = + 17% and total peripheral resistance: Before = + 13% vs. After = + 15%], or in the foot [mean arterial pressure: Before = + 19% vs. After = + 21% and total peripheral resistance: Before = + 16% vs. After = + 16%] cold-pressor tests (P > 0.05). Conclusion Present results demonstrate that 5 weeks of prolonged iterative exposure to hypergravity does not alter the responsiveness of sympathetically mediated circulatory reflexes.
QC 20231120