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Alterations in VO 2 max and the VO 2 plateau with manipulation of sampling interval
Author(s) -
Astorino Todd A.
Publication year - 2009
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/j.1475-097x.2008.00835.x
Subject(s) - medicine , incidence (geometry) , confidence interval , plateau (mathematics) , zoology , treadmill , respiratory exchange ratio , cardiology , demography , mathematics , heart rate , blood pressure , mathematical analysis , geometry , biology , sociology
Summary Background: The most accepted criterion for confirming attainment of VO 2 max is a plateau in oxygen consumption (VO 2 ) at VO 2 max, but its incidence varies. Aims: To compare VO 2 max and VO 2 plateau incidence across various sampling intervals, and to examine predictors of the change in VO 2 (ΔVO 2 ) at VO 2 max. Methods: Sedentary, recreationally‐active, and endurance‐trained subjects ( n = 108, age = 24·2 ± 6·2 year) completed incremental exercise on the treadmill or cycle ergometer. Gas exchange data were obtained breath‐by‐breath and time‐averaged every 15, 30, and 60 s. VO 2 max attainment was verified with the Taylor et al. (1955) criterion (ΔVO 2 at VO 2 max ≤2·1 ml kg −1 min −1 ). Multiple regression was used to examine predictors of ΔVO 2 at VO 2 max. Results: VO 2 plateau incidence was higher using breath‐by‐breath (81%) and 15 (91%) and 30 s time averaging (89%) versus 60 s averaging (59%). Compared to 60 s averaging, VO 2 max was significantly higher ( P <0·05) when data were obtained breath‐by‐breath and with 15 and 30 s time‐averaging compared to 60 s sampling. VO 2 max was not related to VO 2 plateau incidence. Respiratory rate was a significant predictor of ΔVO 2 at VO 2 max in endurance‐trained subjects. Conclusion: More frequent data acquisition revealed higher VO 2 max and incidence of the VO 2 plateau compared to 60 s time averaging. Secondary criteria to verify VO 2 max attainment should not be used, as they do not discern between subjects who do and do not reveal a plateau in VO 2 at VO 2 max.