ABSTRACT
The circumferences of chest, abdomen, thigh and calf during head-out water immersion up to chin level were measured in 8 healthy male subjects (age 35.4±1.6years old, body mass index 23.7±1.6kg/m<sup>2</sup>) in standing and sitting positions. The circumferences of chest, abdomen, thigh and calf decreased significantly during immersion in standing position. The circumferences of chest, abdmen and thigh decreased significantly in sitting position. The circumference of chest decreased from 90.6±3.4 to 90.1±3.1cm, that of abdomen decreased from 81.4±2.8 to 80.6±2.5cm, that of thigh decreased from 47.1±1.6 to 46.6±1.8cm, and that of calf decreased from 37.7±1.8 to 37.2±1.8cm during immersion in standing position. As the body surface area is about 1.6m<sup>2</sup>, the decrease in the volume of human body is considered to be 730cm<sup>3</sup> or less when the body shape change during immersion is not taken into considerarion.