Does NIRS-derived total haemoglobin correlate with femoral artery blood flow during recovery from resistance exercise?
NIRS-derived total haemoglobin demonstrates a strong relationship with Doppler ultrasound blood flow during the recovery period of dynamic resistance exercise, suggesting it is a reliable indicator of muscle blood flow changes.
Blood flow changes in response to exercise have been attributed, among other factors, to the effect of vasodilators factors on the microvasculature, suggesting a close relationship between small blood vessels and conducting arteries. The main purpose of this study was to determine the relationship between the changes in near infrared spectroscopy (NIRS) -derived total haemoglobin (tHb) and muscle oxygen saturation (SmO2) signals and femoral artery blood flow in response to resistance exercise at fast- and slow-velocity muscle contraction. The study randomised crossover design included twelve participants. NIRS and blood flow measurements were continuously monitored before, during, and 5 min after the exercise protocol. There was a significant correlation between tHb reperfusion slope (tHbslope) and peak blood flow (BFpeak) after slow- and fast-velocity muscle contraction (r = 0. 83, p = 0. 0008 and r = 0. 72, p = 0. 0080, respectively). No significant correlation existed between the SmO2 reperfusion slope (SmO2ₛlope) and BFpeak after both slow- and fast-velocity muscle contraction exercise (r = −0. 46, p = 0. 1253 and r = 0. 33, p = 0. 2841, respectively). This study demonstrated a strong relationship between the NIRS-derived tHb and Doppler ultrasound BF during the recovery period of dynamic resistance exercise at both slow- and fast-velocity contraction.
Álvares et al. (Thu,) studied this question.