Using a Portable Near-infrared Spectroscopy Device to Estimate The Second Ventilatory Threshold

Abstract

A breakpoint in a portable near-infrared spectroscopy (NIRS) derived deoxygenated haemoglobin (deoxy[Hb]) signal during an incremental VO2max running test has been associated with the second ventilatory threshold (VT2) in healthy participants. Thus, the aim was to examine the association between this breakpoint (NIRS) and VT2 in well-trained runners. Gas exchange and NIRS data were collected during an incremental VO2max running test for 10 well-trained runners. The breakpoint calculated in oxygen saturation (StO2) and the VT2 were determined and compared in terms relative to %VO2max, absolute speed, VO2, and maximum heart rate (HRmax). There were no significant differences (p>0.05) between the breakpoint in StO2 and VT2 relative to %VO2max (87.00±6.14 and 88.28 ± 3.98 %), absolute speed (15.70±1.42 and 16.10±1.66 km·h−1), VO2 (53.71±15.17 and 54.66±15.57 ml·kg−1·min−1), and%HRmax (90.90±4.17 and 91.84±3.70%). There were large and significant correlations between instruments relative to%VO2max (r=0.68, p<0.05), absolute speed (r=0.86, p<0.001), VO2 (r=0.86, p<0.001), and %HRmax (r=0.69; p<0.05). A Bland and Altman analysis of agreement between instruments resulted in a mean difference of − 1.27±4.49%, −0.40±0.84 km·h−1,−0.90±3.07 ml·kg−1·min−1, and − 0.94±3.14 for %VO2max, absolute speed, VO2, and %HRmax, respectively. We conclude that a portable NIRS determination of the StO2 breakpoint is comparable with VT2 using gas exchange and therefore appropriate for use in determining exercise training above VT2 intensity. This is the first study to analyze the validity with the running mode using a NIRS portable device.

Determination of Second Lactate Threshold Using Near-infrared Spectroscopy in Elite Cyclists

“…In running it has been shown that the SmO 2 breakpoint is be able to predict VT 2 using 10 well-trained runners (5 men and 5 women) [22]. However, in both studies, a possible limitation was the small sample size, as the authors themselves acknowledge.…”

“…Previous findings have shown the relationship between the HHb or SmO 2 breakpoint and other parameters such as RCP, CP, VT 2 or MLSS 2 3 5 9 19 22 23 24 25 26 using different devices in cyclists, runners and rowers. Of all these, the Humon Hex device only was used in two studies.…”

Changes in Muscle Oxygen Saturation Measured Using Wireless Near-Infrared Spectroscopy in Resistance Training: A Systematic Review

“…Importantly, NIRS devices allow one aspect of the muscle response (SmO 2 ) to be monitored during an exercise protocol. In the literature, the muscular response of SmO 2 using NIRS during other physical exercise protocols has been highlighted, observing a significant correlation with the maximum lactate in steady state and the critical power [32] and the second ventilatory threshold [33], where the use of these devices has been indicated as a contribution in optimizing and managing the physical response of the athlete in endurance exercises [34,35]. However, despite the lack of research in the area of resistance training and SmO 2 , the compilation of information presented in this work may contribute to position NIRS devices as an instrument to be used during muscle strength training as a useful alternative, being functional and low cost during the evaluation and planning of muscle strength protocols, optimizing the prescription and management of physical performance in healthy adults.…”

Post-COVID-19 Syndrome and the Potential Benefits of Exercise

“…New trends in resistance and cardiopulmonary training methods appeal to more individualized regimes with a variety of exercises, stimuli and intensities, which are controlled by incorporating new technologies and monitoring tools. Current training methods are based on new approaches to monitoring exercise intensity (e.g., rate of force development, movement velocity), technical execution (e.g., biomechanics, electromyography), readiness (e.g., heart rate variability) and physiological responses (e.g., ventilation, lactate, core temperature, heart rate, muscle oxygen saturation) while providing biofeedback in real time, ensuring the accomplishment of targeted results [125][126][127][128][129][130]. Likewise, a number of portable devices, wearable tools and apps for physical activity and fitness are emerging, making remote control of the patients' evolution possible [131].…”