Blood pressure, hemodynamic, and thermal responses after cycling exercise

Seated recovery [at 5, 15, 20, 40, and 60 min (R5,15,20,40,60)] body temperature (T) and blood pressure were examined after 45 min of cycling exercise (54 +/- 5% maximal O2 uptake) in 12 normotensive males to study the relationship between postexercise thermal and hemodynamic responses. Data were analyzed with a repeated-measures analysis of variance. Systolic (SBP, R15,20,40; P < 0.01) and mean arterial (MAP, R15,20; P < 0.05) blood pressures were significantly lower, but diastolic blood pressure (DBP) was unchanged. Heart rate (R5,15,20, P < 0.001) was above that measured at rest. Decreases in mean skin T (Tsk, R15,20,60; P < 0.01) and increases in core T (Tc, R5,15,20; P < 0.01) were found. Significant negative correlations averaging -0.68 (R15,20,40) and -0.69 (R15,20,40) were demonstrated for Tsk and SBP and MAP, respectively. Increases in thigh Tsk (R5,15,20; P < 0.00001) and decreases in calf (R15,20,40,60; P < 0.00001) and chest (Tchest, R5,15,20,40; P < 0.00001) Tsk were found. Significant negative correlations averaging -0.67 (R5,15,20,40) and -0.71 (R20,40,60) were demonstrated for Tchest and SBP and MAP, respectively. Inverse relationships between various regional Ts and blood pressure and the increased R Tc suggest a vasodilatory response in the visceral organs and/or lower limbs leading to a pooling of blood and transient decreases in blood pressure by a reduced venous return, although not affecting stroke volume and cardiac output.