Open AccessEvaluating the NIRS-derived microvascular O2 extraction “reserve” in groups varying in sex and training status using leg blood flow occlusions
Author(s) -
Erin Calaine Inglis,
Danilo Iannetta,
Juan M. Murias
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0220192
Subject(s) - blood flow , plateau (mathematics) , hemoglobin , medicine , myoglobin , cardiology , anatomy , zoology , chemistry , biology , mathematics , biochemistry , mathematical analysis
It has been demonstrated that the plateau in the near-infrared spectroscopy (NIRS) derived deoxygenated hemoglobin and myoglobin (deoxy[Hb+Mb]) signal (i.e., deoxy[Hb+Mb] PLATEAU ) towards the end of a ramp-incremental (RI) test does not represent the upper-limit in O 2 extraction of the vastus lateralis (VL) muscle, given that an O 2 extraction reserve has been recently observed. This study aimed to investigate whether this O 2 extraction reserve was present in various populations and whether it exhibited sex- and/or training- related differences.Sixteen men- 8 untrained (27±5 years; 83±11 kg; 179±9 cm), 8 trained (27±4 years; 82±10 kg; 182±8 cm) and 9 trained women (27±2 years; 66±10 kg; 172±6 cm) performed a RI cycling test to exhaustion. The NIRS-derived deoxy[Hb+Mb] signal was measured continuously on the VL as a proxy for O 2 extraction. A leg blood flow occlusion (i.e., ischemia) was performed at rest (LBF OCC 1) and immediately post the RI test (LBF OCC 2).No significant difference was found between the deoxy[Hb+Mb] amplitude during LBF OCC 1 and the deoxy[Hb+Mb] PLATEAU ( p >0.05) nor between baseline (bsln) deoxy[Hb+Mb] values. deoxy[Hb+Mb] amplitude during LBF OCC 2 was significantly greater than LBF OCC 1 and at deoxy[Hb+Mb] PLATEAU ( p <0.05) with group means ~30–45% higher than the deoxy[Hb+Mb] PLATEAU and LBF OCC 1 ( p <0.05). No significant differences were found between groups in O 2 extraction reserve, regardless of sex- or training-statusThe results of this study demonstrated the existence of an O 2 extraction reserve in different populations, and that neither sex- nor training-related differences affect the amplitude of the reserve.