Some effects of breathing oxygen before and after exercise

¹ Physiology of Exercise Laboratory, University of Kansas, Lawrence, Kansas

Athletes in better than average physical condition breathed 100% O₂ during 6 minutes of rest, air during 5 minutes of treadmill running at 8 m.p.h. and O₂ during 19 minutes of recovery. The results were compared with a control procedure in which the same subjects breathed air throughout. It was found that the experimental procedure: a) did not significantly facilitate recovery as based upon payment of O₂ debt, measured by a closed-circuit spirometric method; b) depressed the pulse rate during the first 2 minutes of exercise and during the recovery period; c) caused the respiratory rate to increase at rest, to decrease during the initial part of the recovery period, and to increase during the latter part of the recovery period; d) increased the percentage of O₂ saturation of blood hemoglobin, as measured by an ear oximeter, during rest and recovery. Lower oximeter readings were found during the latter part of the exercise period.