The relations between age inactivity and physiological responses to exercise

The studies described have been concerned with two previous untried techniques for measuring the response to exercise. The general aim in both studies was to investigate the relations-between age, activity and the response to exercise (physical condition). In the first study (Part A) the response to exercise was measured using a bicycle ergometer pedalled with one leg. The subjects were in hospital for a meniscectomy. The results showed that bedrest as a model of inactivity caused a decline in physical condition. It also showed that the decline was greatest in those who were initially in the best condition. The older subjects deteriorated less and this appeared to be because their initial condition was the poorest. In the second study (Part B) a method for measuring the response to exercise was developed which is suitable for use with elderly and frail subjects who could not be tested using existing methods. The method consists of self-paced walking at several speeds in a free situation, combined with the tape recording of heart rate and footfall. The assessment of physical condition which can be obtained is the heart rate at a standard walking speed. It was found to correlate with a conventional assessment made using a bicycle ergometer in which the heart rate was standardised on oxygen uptake adjusted for body weight. No age differences have been found in physical condition measured in this way but significant differences were found in performance. The older subjects (aged. between 60 and 80 years) of both sexes walked more slowly than the younger subjects (aged about 20 years) and the older men were found to walk with a shorter stride. These differences may also reflect levels of daily activity