健常成人における温水プール入水時の血行動態に及ぼす影響 : 心エコー図法による検討

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Exercising in water has become widely accecpted as a popular training program in many athletic gymnasiums. However, surprisingly little information regarding the effects of water immersion, in a heated pool, on cardiovascular responses has been reported to date. Therefore, the cardiovascular responses during bathing in eight healthy men, aged 18-20(mean 19ys), werestudied using the M-mode and pulsed Doppler echocardiography. Bathing was conducted with subjects in the standing position(water depth : each subject's xiphoid level)in a heated poolat 3O℃ . The hear t rate, left atrial dimension(LAD), left ventricular end-diastolic dimension(LVDd) and left ventricular end-systolic dimension(LVDs) standing in air and during water immersion were compared. Furthermlre, to study the effect of water immersion on the left ventricular inflow, the subjects were evaluated with pulsed Doppler echocardiography, which was performed with the sample volume placed at the mitral leaflet tips in the apical 4-chamber projection. The LV inflow measurements comprised peak early filling(E) and peak atrial filling velocities(A) .The measurements were recorded at the baseline(standing in air)and during water immersion in a standing position. Water immersion produced a significant decrease in the heart rate(HR) from 71.4±7.8 to 57.4±4.3 beats/ min(mean±standard deviation) , p=0.0005, but the blood pressure remained unchanged. Water immersion produced a significant increase in the LAD(2.3±0.3 to 3.1±0.3cm, p=0.0001) ,LVDd (4.3±0.3 to 5.2±0.2cm, p=0.0001) and LVDS (3.2±0.3 to 3.7±0.2 cm, p =0.0003). The peak early filling velocity(E) did not change significantly(0.64±0.08to 0.74±0.15m/sec) . The peak atrial velocity(A) decreased from 0.34±0.08 to 0.26±0.06m/sec(p<0.05), while the A/E ratio decreased 0. 54±0.10 to 0.37±0.12m/sec (P < 0.005). These results sugggest that(1)the increase in the venous return when immersing a standing subject in water produced significant inceases in the LAD, LVDd, LVDs, and stroke volume, (2)the increase in the chamber sizes may cause a decrease in the heart rate, (3) the increase in the diastolic interval might reduce the A and A/E ratio. It is concluded that water immersion at30℃ may thus result in a volume overload to the subjects, and not a pressure overload.温水プール入水時の心内径や左室流入血流に及ぼす影響をパルスドプラー法も含めた心エコー図法を用いて検討し，下記のような結果を得た。1.水中での立位では大気中での立位に比し，静脈還流量が増加し，心内径の拡大，すなわちecho windowの拡大により良好な心エコー図記録ができた。2.入水による静水圧の作用により静脈還流量が増加し，左肩径および左室径も拡大し，一同駆出量が増加する。その結果，交感神経刺激の解除，副交感神経の刺激が起こり，心拍数が低下したと考えられる。3.左室流入血流に及ぼす入水の影響は，心房収縮血流の低下が最も著明であった。この機序としては，上記の入水による心拍数の低下(すなわち拡張期の延長)が最も考えられるが，その他の影響も検討しなければならない。4.温水(30℃)プール入水は，被検者にとって圧負荷でなく，容量負荷となることを示唆する。
九州大学の論文

健常成人における温水プール入水時の血行動態に及ぼす影響 : 心エコー図法による検討

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