Abstract

The influence of oxygen breathing upon physical working capacity (PWC170) was evaluated in 17 male subjects (track and field athletes aged 19-24 yrs). Four measurements of PWC170 were made under each of three conditions. Five minute rest intervals were allowed between the four measurements. The three experimental conditions were: (1) breathing air during both rest and exercise (experiment A), (2) breathing 100 02 at rest but air during exercise (experiment B), and (3) breathing air at rest but 100 02 during exercise (experiment C). These PWC170 showed the anticipated gradual decrease with repetition in each experimental condition. However, the average values of PWC170 in experiment C were significantly higher than the average values of PWC170 for experiments A and B. In experiment B, resting heart rates breathing 100 02 4-5 min after the exercise bouts were significantly lower than resting heart rates when breathing air throughout rest and exercise (experiment A), but there was no significant difference of average PWC170 between experiment A and experiment B. These results show that although the heart rate returns more rapidly to its resting level, if 100 02 is breathed during recovery. This has little effect on the subsequent PWC170. Such findings are in keeping with the very limited ability of the human body to store 02. Verf.-Referat