Intensity of exercise in water is not established, because it is difficult to measure in water. The purpose of this study was to evaluate the intensity of treadmill walking in water, and to compare it with walking on land. Subjects were three healthy adult male and females.
　We measured oxygen consumption (Vo₂) and heart rate (HR) in water and on a dry treadmill walking at speeds of 3.5 to 5.5 km/h with in a stepwise increments of 0.5 km/h.
　Water and room temperatures were 29 ～ 30°C.
　The results were as follows :
1) Standing in water showed a lower HR than on land, though Vo₂ in water showed a higher value than that on land.
2) Treadmill walking in water showed higher Vo₂ and HR than walking on land through exercise.
3) The intensity of treadmill walking in water was 28 ～ 35% Vo₂max at 3.5 km/h, 35 ～ 46% Vo₂max at 4.0 km/h, 65 ～ 71% Vo₂max at 5.0 km/h, 76 ～ 85% Vo₂max at 5.5 km/h and that of walking on land was 24 ～ 29% Vo₂max at 3.5 ～ 5.5 km/h.
　It was suggested that walking in water might be adequate for improvement of aerobic work capacity.

DESCENTE SPORTS SCIENCE Vol.13/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE