THE INFLUENCE OF A MODERATE AMOUNT OF PHYSICAL TRAINING ON THE RESPIRATORY EXCHANGE AND BREATHING DURING PHYSICAL EXERCISE

Abstract

Moderate physical training, about an hour daily, increased the load-carrying ability [in 2 subjects] within 1 wk. but the full effect was observed only after 5-7 wks. Any let down in the regularity or amount of daily work soon reduced the load-carrying ability, but even with complete neglect of exercise some of the gain in power was maintained for several months. The percentage of CO2 exhaled and of O absorbed dur-ing work was increased by training, the full effects being reached within 4 or 5 wks. These soon dropped back to the pre-training level when training was dis-continued. The minute-volume of breathing for any given load of work decreased with training, and reached its lowest level in 4-6 wks. This effect disappeared within 4-6 wks. after training was discontinued. In 1 subject the absorption of O was increased as training changed overloads to normal or crest-loads. In another subject a slight decrease in the O consumption of work was evidenced as training proceeded. A decrease in the respiratory quotient of work during training suggested a gain in ability to more adequately reconvert lactic acid into its precursor. The effects of physical training were manifest, in the subject sitting at ease, by a higher percentage output of CO2 and intake of O and by a higher metabolism per sq. meter of body surface.