Azevedo RDA, Forot J, Millet GY, Murias JM. Comparing muscle VO
2 from near-infrared spectroscopy desaturation rate to pulmonary VO
2 during cycling below, at and above the maximal lactate steady state.
J Appl Physiol (1985) 2022;
132:641-652. [PMID:
35112926 DOI:
10.1152/japplphysiol.00754.2021]
[Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscle oxygen uptake (V̇O2m) evaluated from changes in the near-infrared spectroscopy oxygen desaturation slope during a 5-s arterial blood flow occlusion has been proposed as an estimation of the actual V̇O2m. However, its correspondence with pulmonary oxygen uptake (V̇O2p) during exercise remains unknown.
PURPOSE
to investigate the V̇O2m and V̇O2p relationship in females and males in response to prolonged constant-load cycling exercise at different intensities.
METHODS
Eighteen participants (8 females) visited the laboratory on six occasions: 1) ramp incremental test; 2-3) 30-min constant power output (constant-PO) exercise bout to determine the maximal lactate steady state (MLSS); 4-6) constant-PO exercise bouts to task failure at (i) 15% below MLSS (MLSS-15%); (ii) MLSS; (iii) 15% above MLSS (MLSS+15%). V̇O2m was estimated at baseline, at min 5, 10, 20, 30, and at task failure. V̇O2p was continuously recorded during the constant-PO bouts.
RESULTS
V̇O2pand V̇O2m significantly increased from min 5 to min 30 in MLSS condition (all p < 0.05) and from min 5 to min 10 in MLSS+15% condition (all p < 0.05). V̇O2pand V̇O2m were correlated (r2 adj range of 0.70-0.98, all p < 0.001) amongst exercise intensities in both females and males. Additionally, both variables were also correlated when expressed as percent (r2 adj range of 0.52-0.77, all p < 0.001).
CONCLUSION
V̇O2p and V̇O2m responses were similar when exercising below, at, and above the MLSS independently of sex. Most importantly, V̇O2p andV̇O2m were correlated regardless the exercise intensity and sex of the participants.
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