Wolf J P, Nguyen N U, Dumoulin G, Baulay A, Berthelay S
Eur J Appl Physiol Occup Physiol. 1987;56(3):345-9. doi: 10.1007/BF00690903.
The relative influences of the supine posture and of immersion on the renin-aldosterone system (RAS) were studied at rest and during moderate exercise in five healthy men. When supine, resting or immersion to the neck for 20 min in a thermoneutral environment both induced a decrease in plasma renin activity (PRA) when compared with the levels measured after 15 min sitting at rest (resting: -44%, p less than 0.05. Immersion: -45%, p less than 0.05). There was no significant difference in PRA decrease between the two situations. Aldosterone (ALDO) values were lower after supine rest or immersion than those observed after sitting at rest, but the difference was not significant. Two types of exercise at a constant relative work load (40-50% maximal oxygen uptake), namely cycling on an ergocycle in the supine position and free-style swimming, induced increases in PRA and ALDO when compared with the levels measured after 15 min rest when sitting (respectively, PRA = +35%, p less than 0.05, and +45%, p less than 0.05, ALDO = +32%, p less than 0.01 and +35%, p less than 0.05). Increases in PRA and ALDO did not differ between the two exercises. Thus inhibitory effects on RAS of change in external pressure are negligible during water immersion to the neck in the supine position and during swimming at moderate intensity.
在五名健康男性中，研究了仰卧姿势和浸入对肾素-醛固酮系统（RAS）的相对影响，分别在静息状态和中等强度运动期间进行观察。当仰卧时，无论是在热中性环境中静息还是颈部浸入20分钟，与静息坐位15分钟后测得的水平相比，血浆肾素活性（PRA）均降低（静息：-44%，p<0.05；浸入：-45%，p<0.05）。两种情况下PRA降低无显著差异。仰卧休息或浸入后醛固酮（ALDO）值低于静息坐位后观察到的值，但差异不显著。两种在恒定相对工作负荷（最大摄氧量的40 - 50%）下的运动，即仰卧位在测力计上骑自行车和自由泳，与静息坐位15分钟后测得的水平相比，PRA和ALDO均升高（分别为，PRA = +35%，p<0.05，和 +45%，p<0.05；ALDO = +32%，p<0.01和 +35%，p<0.05）。两种运动中PRA和ALDO的升高无差异。因此，在仰卧位颈部浸入水中和中等强度游泳期间，外部压力变化对RAS的抑制作用可忽略不计。
