Cardiovascular Responses to Lower Body Negative Pressure in Endurance and Static Exercise-Trained Men.

摘要

The cardiovascular responses to lower body negative pressure (LBNP) (to -50 torr) were examined in 8 sedentary control (UT), 8 endurance-trained (ET), and 8 weight-trained (WT) human subjects. The results were used to compare and contrast the blood pressure control system of the three subject groups. The primary differences in response included a more effective maintenance of blood pressure, by reason of greater stroke volume and cardiac indices of the WT subjects during (P <0.05). Peripheral vascular resistances were not different (P >0.05) throughout LBNP between the three groups. Therefore, the improved blood pressure maintenance of the WT subjects was attributed to a cardiac effect. The ET subjects were less effective in maintaining blood pressure than UT or WT subjects this finding was apparently due to an attenuated baroreflex sensitivity, as evidence by a significantly (P <0.05) lower delta heart rate/delta systemic blood pressure ratio, 0.99 for ET vs 1.51 and 1.38 for the UT and WT group respectively, calculated from the responses observed from 0 to -50 torr of LBNP. Keywords: Reprints.