Anaerobic threshold and the oxygen consumption–cardiac output relationship during exercise

Abstract

There is some evidence that, above anaerobic threshold (AT), the arteriovenous oxygen difference may increase due to a reduced hemoglobin affinity for oxygen. Thus, it should be expected that above AT, the oxygen consumption to cardiac output (VO 2 /CO) relationship would become steeper compared to below AT since, if a larger amount of O 2 could be extracted from blood, a lower CO would be required for carrying the same O 2 quantity. We tested the possibility that the VO 2 /CO relationship shows a break point after AT, becoming steeper. Cardiodynamics and expired gases were measured with an impedance cardiograph and a mass spectrometer in ten healthy male subjects during an incremental test on a cycle ergometer. We performed three linear regressions for each subject's VO 2 /CO ratio: one for the entire exercise dataset, one for data below AT, and one for data above AT. Statistical comparisons of linear regressions obtained from VO 2 and CO for below and above AT data failed to find any significant difference between these data. This study demonstrates that the slope of the VO 2 /CO relationship does not exhibit a break point at AT. Therefore, it seems that AT does not play a key role in affecting this relationship during incremental exercise.

The physiological evaluation of sports activities of basketball players

“…It is as well necessary to develop aerobic capacity because the efficiency of the gaming activities implementation in oxygen supply of the body is gy processes' disturbed balance, and this property is determined by the level of development of players' aerobic capabilities. This confirms the information available in the literature [3,5,[17][18][19].…”

Graded Exercise Testing Protocols for the Determination of VO2max: Historical Perspectives, Progress, and Future Considerations

“…It has been well established that Q increases at a linear rate similar to VO 2 upon the initiation of incremental to maximal exercise [14–18]. In response to metabolically induced peripheral vasodilation in working skeletal muscle, blood pressure is maintained by increases in HR and SV [16].…”

Prediction of Extravascular Burden of Carbon Monoxide (CO) in the Human Heart

“…8,9 A regression equation for estimation of blood volume was also included in the model. 56 In addition, predictive equations for estimation of cardiac output 3,4,6,18,21,34,37,72 _ Q À Á and heart rate 14,50,83 (HR) as a function of total body oxygen consumption (MRO 2 ) were also developed (Eqs. C.4 and C.6, Appendix C) but were used only when values were not provided by the investigators whose data we simulated.…”

“…In order to account for change in cardiac output with physical activity, we developed a predictive equation for estimating cardiac output, _ Q; as a function of total body oxygen consumption, MRO 2 . Rest and exercise data for cardiac output and MRO 2 from various published papers 3,4,6,18,21,34,37,72 from human subjects are shown in Fig. 14.…”