Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

Distinguishing the effects of convective and diffusive O2 delivery on V̇o2 on-kinetics in skeletal muscle contracting at moderate intensity

“…Furthermore, the dynamic response of capillary hematocrit to contraction has not been studied in large mammals. Indirect evidence suggests that changes of capillary hematocrit observed in rats are similar to those measured in humans using near-infrared spectroscopy (6). Vasodilation and capillary recruitment are other factors that may affect both PS and Q in contracting muscle in vivo (21,35,36,46); however, it is expected that these factors are minimal for this canine muscle preparation.…”

Characterizing near-infrared spectroscopy responses to forearm post-occlusive reactive hyperemia in healthy subjects

“…RSS is residual sum of squared errors for Gompertz (RSS G ), logistic (RSS L ), and exponential (RSS E ) functions * Significantly different from both RSS L and RSS E represents increased microvascular hematocrit (Boushel et al 2001;Kindig et al 2002;Klitzman and Duling 1979 Tran et al (1999) demonstrated that during cuff ischemia of the lower leg, Mb desaturation by NMR reached a maximum value by *4.5 min. Given that Mb content of human skeletal muscle is greater than previously thought (Marcinek et al 2007;Davis 2009), the dynamics of Mb de/resaturation may contribute significantly to the overall kinetics of the NIRS responses during PORH. Consistent with this, the observed time to the inflection point (X 0 ) for deoxy [Hb?Mb] in the present study (16.9 s) is similar to the time constants for Mb resaturation reported by Duteil et al (2004).…”

Effect of pedaling cadence on muscle oxygenation during high-intensity cycling until exhaustion: a comparison between untrained subjects and triathletes

“…It should be considered that ∆deoxy[Hb + Mb] reflects the balance between V O 2M and Q O 2M (i.e., V O 2M /QO 2M ratio) and thus microvascular O 2 extraction [i.e., proportional to C(a−v)O 2 ] (Boone et al 2014;DeLorey et al 2003;Ferreira et al 2006;Grassi et al 2003;Koga et al 2007) and ∆total[Hb + Mb] reflects the increase in microcirculation hematocrit (Hct) during (Boone et al 2014;Davis and Barstow 2013;Poole et al 2013).…”

“…∆deoxy[Hb + Mb] represents variations in the V O 2M /QO 2M ratio in the capillaries, reflecting the change in O 2 extraction [i.e., proportional to C(a−v)O 2 ] in the muscle (DeLorey et al 2003;Grassi et al 2003). Total[Hb + Mb] is a measurement of (oxy[Hb + Mb] + deoxy[Hb + Mb]) and its changes are suggested to represent variations in hematocrit of the microcirculation during exercise (Boone et al 2014;Davis and Barstow 2013).…”