This is particularly for any science nerds, doctors or physiologists out there. This research completed by VL Katz was ground breaking at the time, examining the effects of immersing pregnant women up to their necks in thermoneutral water. The shift in fluid from periphery to central venous system has some far reaching effects on so both homeostatic and nervous systems. All of these effects are taken into account when planning our Aqua4mums classes.
Effects during pregnancy studied by VL Katz:
Exercise in the water offers several physiological advantages to the pregnant woman. The hydrostatic force of water pushes extravascular fluid into the vascular spaces, producing an increase in central blood volume that may lead to increased uterine blood flow. This force is proportional to the depth of immersion. The increase in blood volume is proportional to the woman’s edema. A marked diuresis and natriuresis accompanies the fluid shifts. The buoyancy of water supports the pregnant women. Water is thermoregulating.
Studies of pregnant women exercising in the water have shown less fetal heart rate changes in the water than on land in response to exertion. Pregnant women’s heart rates and blood pressures during water exercise are lower than on land exercise, reflecting the immersion-induced increase in circulating blood volume. The physiology of water exercise offers some compensation for the physiological changes of exercise on land that may beneficially affect pregnancy.
https://www.sciencedirect.com/science/article/abs/pii/S0146000596800218