Journeay W Shane, Jay Ollie, McInnis Natalie H, Leclair Emily, Kenny Glen P
Laboratory of Human Bioenergetics and Environmental Physiology, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada.
Med Sci Sports Exerc. 2007 Aug;39(8):1308-14. doi: 10.1249/mss.0b013e31806865e0.
We evaluated the hypothesis that during recovery from dynamic exercise in the 15 degrees head-down tilt (HDT) position, the attenuation of the fall in mean arterial pressure (MAP), cutaneous vascular conductance (CVC), and sweat rate, and the augmentation of the rate of esophageal temperature (T(es)) decay relative to the upright seated (URS) posture, would be different between males and females.
Fourteen subjects (seven males, seven females) performed two experimental protocols: 1) 15 min of cycle ergometry at 75% VO2peak and then 60 min of recovery in the URS posture; or 2) 15 min of cycle ergometry at 75% VO2peak and then 60 min of recovery in the 15 degrees HDT position. Mean skin temperature, Tes, CVC, sweat rate, cardiac output (CO), stroke volume (SV), heart rate (HR), total peripheral resistance (TPR), and MAP were recorded at baseline; end of exercise; 2 min, 5 min, 8 min, 12 min, 15 min, and 20 min after exercise; and every 5 min until the end of recovery (60 min).
During recovery from exercise, we observed significantly greater values for MAP, CVC, and sweat rate with HDT in comparison with the URS recovery posture (P <or= 0.05). The magnitude of these responses to HDT did not differ between genders, and a significantly lower T(es) was subsequently observed with HDT for the duration of recovery (P <or= 0.05) for both males and females. In the URS posture, females showed a greater decrease of postexercise MAP than did males (P <or= 0.05). At the end of 60 min of recovery, T(es) remained significantly elevated above baseline with the URS recovery posture (P <or= 0.05). With HDT, T(es) returned to baseline after 20 min.
HDT attenuates the reductions in MAP, CVC, and sweat rate observed after exercise in a gender-independent manner, and this likely is attributable to a nonthermal baroreceptor influence.
我们评估了这样一个假设，即在15度头低位倾斜（HDT）姿势下从动态运动恢复过程中，平均动脉压（MAP）、皮肤血管传导率（CVC）和出汗率下降的衰减，以及相对于直立坐姿（URS）姿势，食管温度（T(es)）下降速率的增加，在男性和女性之间会有所不同。
14名受试者（7名男性，7名女性）进行了两个实验方案：1）以75%的最大摄氧量（VO2peak）进行15分钟的周期测力计运动，然后在URS姿势下恢复60分钟；或2）以75%的VO2peak进行15分钟的周期测力计运动，然后在15度HDT姿势下恢复60分钟。在基线、运动结束时、运动后2分钟、5分钟、8分钟、12分钟、15分钟和20分钟以及恢复结束前（60分钟）每隔5分钟记录平均皮肤温度、T(es)、CVC、出汗率、心输出量（CO）、每搏输出量（SV）、心率（HR）、总外周阻力（TPR）和MAP。
在运动恢复过程中，我们观察到与URS恢复姿势相比，HDT时MAP、CVC和出汗率的值显著更高（P≤0.05）。这些对HDT的反应程度在性别之间没有差异，并且在恢复期间，男性和女性在HDT时随后观察到的T(es)均显著更低（P≤0.05）。在URS姿势下，女性运动后MAP的下降幅度比男性更大（P≤0.05）。在60分钟恢复结束时，URS恢复姿势下T(es)仍显著高于基线（P≤0.05）。在HDT时，T(es)在20分钟后恢复到基线。
HDT以与性别无关的方式减弱了运动后观察到的MAP、CVC和出汗率的降低，这可能归因于非热压力感受器的影响。
