The maximally attainable V̇ o 2 during exercise in humans: the peak vs. maximum issue

• Published in: Journal of applied physiology (1985) Vol. 95; no. 5; pp. 1901 - 1907
• Main Authors: Day, J. R., Rossiter, H. B., Coats, E. M., Skasick, A., Whipp, B. J.
• Format: Journal Article
• Language: English
• Published: 01-11-2003
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00024.2003

The quantification of maximum oxygen uptake (V̇o
2 max
), a parameter characterizing the effective integration of the neural, cardiopulmonary, and metabolic systems, requires oxygen uptake (V̇o
2
) to attain a plateau. We were interested in whether a V̇o
2
plateau was consistently manifest during maximal incremental ramp cycle ergometry and also in ascertaining the relationship between this peak V̇o
2
(V̇o
2 peak
) and that determined from one, or several, maximal constant-load tests. Ventilatory and pulmonary gas-exchange variables were measured breath by breath with a turbine and mass spectrometer. On average, V̇o
2 peak
[3.51 ± 0.8 (SD) l/min] for the ramp test did not differ from that extrapolated from the linear phase of the response in 71 subjects. In 12 of these subjects, the V̇o
2 peak
was less than the extrapolated value by 0.1-0.4 l/min (i.e., a “plateau”), and in 19 subjects, V̇o
2 peak
was higher by 0.05-0.4 l/min. In the remaining 40 subjects, we could not discriminate a difference. The V̇o
2 peak
from the incremental test also did not differ from that of a single maximum constant-load test in 38 subjects or from the V̇o
2 max
in 6 subjects who undertook a range of progressively greater discontinuous constant-load tests. A plateau in the actual V̇o
2
response is therefore not an obligatory consequence of incremental exercise. Because the peak value attained was not different from the plateau in the plot of V̇o
2
vs. work rate (for the constant-load tests), the V̇o
2 peak
attained on a maximum-effort incremental test is likely to be a valid index of V̇o
2 max
, despite no evidence of a plateau in the data themselves. However, without additional tests, one cannot be certain.