ABSTRACT
Moderate-intensity physical activity is recommended to promote health, and augment peak oxygen transport, thus reducing the risk of chronic disease, and delaying functional loss in the elderly. The optimal method of prescribing the recommended intensity of effort [approximately 50% of oxygen intake reserve ( V(.)O(2reserve)) or heart rate reserve (HR(reserve))] remains unclear for this age group. Our aim was to develop a new field-method of prescribing exercise for the elderly, based on walking velocity measured over a 5-m distance. Walking velocities were calculated from the time taken to move from the 3-m to the 8-m mark on an 11-m, straight, flat walkway. Interrelationships of preferred and maximal walking velocities with traditional laboratory measurements [peak isometric knee-extension strength and maximal oxygen intake ( V(.)O(2max))] were examined in 10 healthy male and 13 healthy female volunteers, aged 65-74 years. Percentages of oxygen intake reserve (% V(.)O(2reserve)) and heart rate reserve (%HR(reserve)) were also determined when walking at 30-70% of maximal velocity. Preferred and maximal walking velocities were significantly correlated ( r>0.60; P<0.05), the former corresponding to an average of 53-54% of the latter in both men and women. Maximal walking velocity was significantly correlated with both peak knee-extension torque ( r>0.90; P<0.05) and V(.)O(2max) ( r>0.80; P<0.05). As a result, the % V(.)O(2reserve) and %HR(reserve) showed a regular and linear relationship to various submaximal walking velocities. For both men and women, 40-60% of the maximal walking velocity corresponded to about 30-50% of V(.)O(2reserve) and HR(reserve). Approximately 60% of the maximal walking velocity (or 110-115% of the preferred walking velocity) represents an appropriate intensity of moderate exercise for the typical elderly person. Our preliminary data suggest that a prescription based on walking velocity over the 5-m distance allows the healthy elderly to exercise simply, safely, and effectively.
