Goldberg D I, Shephard R J
J Appl Physiol Respir Environ Exerc Physiol. 1980 May;48(5):833-7. doi: 10.1152/jappl.1980.48.5.833.
A CO2 rebreathing method has been modified to allow nonsteady-state measurements of cardiac output during and after recovery from upright bicycle ergometer exercise. Data obtained on 10 healthy men who continued loadless pedaling for 4 min following a progressive exercise bout to 70% of maximum oxygen intake showed a rapid recovery of heart rate. In contrast, there was an early 29% increase of stroke volume and 216 s after exercise the stroke volume was still larger than the final exercise reading. It appears that if venous return is facilitated, the metabolic needs of recovery plus the small cost of loadless pedaling are met by maintaining stroke volume rather than heart rate.
