Oxygen uptake and heart rate differences between walking on land and in water in the elderly

The purpose of this study was to determine the effects of head-out-of-water immersion (HOI) on elderly subjects' heart rate (HR) and oxygen uptake (VO2) responses to graded walking exercise. Subjects were 15 elderly participants, who selected three walking speeds and exercised for 6 min at each intensity on land and in the water. HOI exercise was carried out with subjects immersed to the level of the axilla. HR response at a given VO2 during walking with HOI was similar to the values found for walking on land, in contrast to published data on young subjects. The findings are consistent with the hypothesis that water immersion-induced central redistribution of blood volume changes with advancing age and may lead to a difference in the HR-VO2 relationship during HOI walking in the elderly compared to the young. This has important implications for prescribing exercise to the elderly when using treadmill HR values for HOI walking training.