Thermoregulatory and nonthermoregulatory interaction in human cardiovascular control

Abstract

Purpose. Study #1 examined the responses to facial immersion under states of altered cardiac filling. Study #2 sought to examine changes in postexercise hemodynamics and skin blood flow (SkBF) when lower blood pooling was manipulated using lower body pressure. Methods. Study #1---Six male subjects participated. They performed 30-s apneic facial immersions under: LBNP, LBPP, during post-exercise hypotension (PEH); & Control. MAP, HR, and SkBF were measured. Study #2---Subjects were exposed to LBNP, LBPP; or no pressure after 15-mins of cycle exercise at 70% of VO2 peak. HR, CO, SV, MAP, TPR, & SkBF, skin and esophageal temperature were recorded. Conclusions. Study #1---Cardiac parasympathetic response during facial immersion can be attenuated when cardiac filling is compromised. Study #2---(1) LBPP accelerates recovery of baseline hemodynamics while LBNP exacerbates the postexercise hemodynamic state relative to control. (2) Altering postexercise hemodynamics via LBPP may affect thermal responses.