PHYSICAL TRAINING IN SEDENTARY MIDDLE-AGED AND OLDER MEN .3. CARDIAC OUTPUT AND GAS EXCHANGE AT SUBMAXIMAL AND MAXIMAL EXERCISE

Fifteen previously sedentary men (38-55 years old) participated in an endurance training program which consisted of running for 2-3 half-hours a week for 8-10 weeks. Maximal oxygen uptake increased in all subjects, mean increase from 2.68 to 3.06 l/min, i.e. 14 per cent. This increase was brought about by a 13 per cent increase in maximal cardiac output, from 18.7 to 21.1 l/min. Heart rate was 8-17 beats/min lower during submaximal exercise. The maximal heart rate decreased by 6 (from 182 to 176) beats/min. Thus stroke volume was increased 7-17 ml at submaximal and 17 ml (16 per cent) at maximal exercise. Heart volume determined from X-rays did not change. After the training, mean arterial blood pressure was on the average 5 mm Hg lower at a given submaximal oxygen uptake; no change was observed at maximal exercise. © 1969 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.