NIRS-Derived Muscle-Deoxygenation and Microvascular Reactivity During Occlusion–Reperfusion at Rest Are Associated With Whole-Body Aerobic Fitness


Purpose: Near-infrared spectroscopy (NIRS) indices during arterial occlusion–reperfusion maneuver have been used to examine the muscle’s oxidative metabolism and microvascular function—important determinants of whole-body aerobic-fitness. The association of NIRS-derived parameters with whole-body VO2max was previously examined using a method requiring exercise (or electrical stimulation) followed by multiple arterial occlusions. We examined whether NIRS-derived indices of muscle deoxygenation and microvascular reactivity assessed during a single occlusion–reperfusion at rest are (a) associated with maximal/submaximal indices of whole-body aerobic-fitness and (b) could discriminate individuals with different VO2max. We, also, investigated which NIRS-parameter during occlusion–reperfusion correlates best with whole-body aerobic-fitness. Methods: Twenty-five young individuals performed an arterial occlusion–reperfusion at rest. Changes in oxygenated- and deoxygenated-hemoglobin (O2Hb and HHb, respectively) in vastus-lateralis were monitored; adipose tissue thickness (ATT) at NIRS-application was assessed. Participants also underwent a maximal incremental exercise test for VO2max, maximal aerobic velocity (MAV), and ventilatory-thresholds (VTs) assessments. Results: The HHbslope and HHbmagnitude of increase (occlusion-phase) and O2Hbmagnitude of increase (reperfusion-phase) were strongly correlated with VO2max (r = .695–.763, p textless .001) and moderately with MAV (r = .468–.530; p textless .05). O2Hbmagnitude was moderately correlated with VTs (r = .399–.414; p textless .05). After controlling for ATT, the correlations remained significant for VO2max (r = .672–.704; p textless .001) and MAV (r = .407; p textless .05). Individuals in the high percentiles after median and tritile splits for HHbslope and O2Hbmagnitude had significantly greater VO2max vs. those in low percentiles (p textless .01–.05). The HHbslope during occlusion was the best predictor of VO2max. Conclusion: NIRS-derived muscle deoxygenation/reoxygenation indices during a single arterial occlusion–reperfusion maneuver are strongly associated with whole-body maximal indices of aerobic-fitness (VO2max, MAV) and may discriminate individuals with different VO2max.

Research Quarterly for Exercise and Sport