Reliability of near infrared spectroscopy (NIRS) for measuring forearm oxygenation during incremental handgrip exercise

Abstract

The purpose of this study was to test the reliability of a new handgrip exercise protocol measuring forearm oxygenation in 20 healthy subjects on two occasions. The retest took place 48 h later and at the same time of the day. The incremental exercise consisted of 2 min steps of cyclic handgrip contraction (1/2 Hz) separated by 1 min of recovery. The exercise started at 20% MVC, was increased with 10% MVC each step and was performed until exhaustion (69.5 and 73% MVC). Near infrared spectroscopy (NIRS) was used to measure deoxygenation (deoxy[Hb + Mb]) and oxygen saturation (SmO(2)) in the forearm muscles. Prior to the exercise protocol an arterial occlusion of the forearm was performed until deoxy(Hb + Mb) did no longer increase. Maximal increase in deoxy[Hb + Mb] during 10 s of each exercise bout was expressed relative to the occlusion amplitude. ICC was used to examine the test-retest reliability. Significant ICC's were reported at 50% (r = 0.466, p = 0.017) and 60% MVC (r = 0.553, p = 0.005). The group mean of the maximum increase in oxygen extraction was 45.6 ± 16.7% and at the retest 44.9 ± 17.0% with an ICC of r = 0.867 (p < 0.001) which could be classified (Landis and Koch 1979) as almost perfect. The absolute SmO(2) values showed reliable ICC's for every submaximal intensity except at 60% MVC. An ICC of r = 0.774 (p < 0.001) was found at maximal intensity. The results of the present study show that deoxy[Hb + Mb] and SmO(2) responses during this protocol are highly reliable and indicate that this protocol could be used to get insight into deoxygenation and oxygen saturation in a population with low exercise tolerance.

Reliability of telemetric electromyography and near-infrared spectroscopy during high-intensity resistance exercise

“…The current investigation suggests that the inter-test reliability of NIRS during multi-joint resistance exercise is lower than reported in previous investigations using isokinetic and isometric exercise (Celie et al, 2012;Kell et al, 2004;Pereira et al, 2005;Tanimoto and Ishii, 2006). While great attention was paid to standardize experimental conditions between exercise trials, several factors may have contributed to the day-to-day variability observed.…”

“…While previous research has established the test-retest reliability of NIRS to monitor muscle oxygenation status during various exercise protocols (Celie et al, 2012;Kell et al, 2004;Pereira et al, 2005;Tanimoto and Ishii, 2006), this research is the first to assess the reproducibility of NIRS during isotonic multi-joint resistance exercise. The current data demonstrate that at most intensities and set volumes, HbO 2min and HHb max values display acceptable intra-test reliability.…”

“…NIRS data during knee extension exercise has also yielded moderate to strong ICC values during both isokinetic (0.73-0.97) (Pereira et al, 2005) and isotonic (ICC = 0.85 and coefficient of variation [CV] = 0.07%) (Tanimoto and Ishii, 2006) (Celie et al, 2012). While these studies have reported the reliability of NIRS during single-joint resistance exercise, no data have reported on the reliability of NIRS measures during multi-joint isotonic resistance exercise.…”

Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients

“…24,28 The NIRS device, placed at the forearm, noninvasively, monitored changes in muscle oxygenation, by measuring micromolar (µmol/L) relative changes from baseline for oxygenated, deoxygenated, and total hemoglobin. 29,30 NIRS also assessed the tissue saturation index (TSI), as an absolute parameter for muscle oxygenation. Muscle microvascular function was assessed during reactive hyperemia, as previously described.…”

“…Within the skeletal muscle, light is absorbed by hemoglobin in small arterioles, capillaries, and venules of the microcirculation, causing changes in oxygenated, deoxygenated, and total hemoglobin NIRS signals, and provides information on the balance of oxygen delivery and utilization. 29,31,37 The NIRS signals arise predominantly from capillaries as these microvessels compose the largest portion of vascular volume in skeletal muscle (>90%), and the NIRS light can only pass through vessels <1 mm. 25,31,37,38 Thus, NIRS signals mainly reflect changes in capillary (hemoglobin related) oxygen levels and provide information on the microcirculation.…”