Name: Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with One Stop Shop Near-infrared Spectroscopy (Video) | JoVE Journal
Uploaded: 2018-02-20T15:00:00.000+00:00
Duration: 9 min 4 s
Description: Learn to noninvasively assess skeletal muscle oxidative capacity, reactive hyperemia, and neurovascular coupling using near-infrared spectroscopy. This method enables comprehensive evaluation of macro and microvascular function in clinical settings.

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5 minutes

This work was supported by a University of Texas at Arlington Interdisciplinary Research Program grant.

This protocol follows the guidelines of the institutional review board at the University of Texas at Arlington and conforms to the standards set by the latest version of the Declaration of Helsinki. Accordingly, written informed consent was (and should be) obtained prior to commencement of research procedures.
1. Instrumentation
NOTE: The following instrumentation description is based on the near-infrared (NIR) spectrometer and data acquisition system used in our lab (see Table of Materials). Thus, the instructions include steps that are necessary for the optimal function of these devices. These steps include the calibration of the NIR probe using the accompanying software and calibration phantom, and the application of a dark cloth to exclude ambient light. In the event that different data collection hardware and/or software are used, investigators should consult their own specific user manuals for calibration and ambient light considerations. Figure 1 illustrates the experimental set-up and instrumentation described immediately below.
<ol>
	<li>Instruct the subject to lie supine with their legs inside a lower body negative pressure (LBNP) chamber (Figure 1A), so that their belt line is approximately even with the opening to the LBNP box. For instructions on how to build a LBNP chamber, see References17.</li>
	<li>Place three electrocardiogram electrodes on the subject: two in an inferior, mid-clavicular location and one on the subject's left side medial to the iliac crest. This configuration provides the best results due to limited access to the lower limbs, instrumentation of the upper limbs, and arm movement during hand grip exercise.</li>
	<li>Place a non-invasive blood pressure monitor module on the subject's dominant wrist. Place the finger blood pressure cuffs on each finger and connect them to the module (Figure 1B). Ensure the finger blood pressure cuffs are properly calibrated according to the user's manual accompanying your device.</li>
	<li>Instruct the subject to grasp a hand grip dynamometer (HGD) with their non-dominant arm in a slightly abducted position. The arm should be comfortably positioned on a bedside table. The distance and angle of the HGD should be adjusted to allow for optimal grip strength with minimal arm movement (Figure 1C).</li>
	<li>Secure the HGD to a bedside table.</li>
	<li>Measure the maximum voluntary contraction (MVC) of the participant. Tell the participant that, when prompted, they must squeeze the HGD as hard as possible while only utilizing the muscles in the hand and forearm. Instruct the subject that they must refrain from recruiting their upper arm, chest, shoulder, or abdominal muscles when performing the maximum grip.</li>
	<li>Repeat Step 1.6 three times, separated by at least 60 s. Record the maximum force achieved (best of 3). This maximum force will be used to calculate the exercise intensity for skeletal muscle oxidative capacity and neurovascular coupling (below).</li>
	<li>Place a rapid-inflation cuff around the upper arm of the exercising hand. Connect the airline from the rapid inflation controller to the cuff.</li>
	<li>Identify the flexor digitorum profundus. Use a skin marker to demarcate the borders of the palpable muscle.</li>
	<li>Ensure that the NIR spectrometer is properly calibrated according to the user's manual included with your device. Clean the skin over which the NIR probe will be positioned with an alcohol prep wipe.</li>
	<li>Place the NIR probe over the center of the belly of the muscle (flexor digitorum profundus) and affix it securely to the forearm.</li>
	<li>Wrap the probe and forearm with dark cloth, minimizing interference from ambient light (Figure 1C, Figure 1D).</li>
	<li>When ready to perform the functional sympatholysis portion of the study, seal the subject into the LBNP chamber.</li>
</ol>
2. Skeletal Muscle Oxidative Capacity
NOTE: A representative data tracing illustrating the experimental procedure for measuring skeletal muscle oxidative capacity is depicted in Figure 2. This experimental approach has previously been validated against in vivo phosphorus MRS18 and in situ muscle respirometry19, and is gaining widespread acceptance20.
<ol>
	<li>Instrument the subject as indicated above (Instrumentation).</li>
	<li>Instruct the subject to lie still for 2 min while monitoring deoxyhemoglobin (HHb) and oxyhemoglobin (HbO2) via the NIR probe. 
	NOTE: This rest period allows the subject to recover from any movement artifact associated with the instrumentation process, and ensures stable baseline measurements. If after 2 min no significant fluctuations have occurred, the subject may be considered at a steady state, or resting baseline.</li>
	<li>Prior to cuff occlusion, notify your subject that you will be inflating the cuff. Inflate the upper arm cuff at least 30 mmHg above systolic blood pressure for 5 min (i.e., suprasystolic). Instruct the subject to keep their arm as still and relaxed as possible both during cuff inflation and following cuff deflation. 
	NOTE: This 5 min brachial artery cuff occlusion protocol closely reflects the currently accepted clinical standard for vascular occlusion tests21,22,23,24,25.</li>
	<li>Record the initial/baseline value (prior to cuff occlusion) and the nadir value of tissue saturation (StO2) during the cuff occlusion and determine the midpoint between these two values. 
	<img alt="Blood oxygenation equation (StO₂), showing ratio of HbO₂ to total hemoglobin, formula representation." src="/files/ftp_upload/57317/57317eq1.jpg" data-altupdatedat="1788250015000" data-alt="Equation 1"></li>
	<li>Allow the subject to recover from the cuff occlusion and return to the resting baseline values. Once the subject has maintained a resting baseline for at least 1 full min, continue to the next step.</li>
	<li>Instruct subject to squeeze and maintain an isometric hand grip at 50% of their MVC. Encourage the subject to maintain their isometric contraction until the tissue desaturates by 50%. Upon achieving this value, tell the subject to relax their hand and inform them that no more exercise or movement is needed.</li>
	<li>Within 3 - 5 s following exercise cessation, administer the following rapid cuff occlusion series (one series = 1 inflation + 1 deflation), as previously established18: 
	Series #1 - 6: 5 s on/5 s off 
	Series #7 - 10: 7 s on/10 s off 
	Series #11 - 14: 10 s on/15 s off 
	Series #15 - 18: 10 s on/20 s off</li>
	<li>After completing the 18th inflation/deflation series, instruct the subject to rest, allowing tissue saturation to return to initial baseline values. After these values have remained consistent for at least 2 min, repeat steps 2.4 and 2.5.</li>
	<li>Calculating Skeletal Muscle Oxidative Capacity
	<ol>
		<li>Calculate the slope of change in the StO2for each of the individual 18 cuff occlusions, forming the monoexponential recovery points illustrated in Figure 2C.</li>
		<li>Fit the calculated data from 2.7 to the following monoexponential curve18,19,26 
		y = End - Δ x e-kt 
		NOTE: 'y' is the relative muscle oxygen consumption rate (mV̇O2) during cuff inflation, 'End' represents the mV̇O2 immediately following the cessation of exercise; delta ('Δ') signifies the change in mV̇O2 from rest to the end of exercise; 'k' is the fitting rate constant; 't' is time. Tau is calculated as 1/k.</li>
	</ol>
	</li>
</ol>
3. Reactive Hyperemia
NOTE: A representative data tracing illustrating the experimental procedure for measuring reactive hyperemia is depicted in Figure 3.
<ol>
	<li>With the subject lying supine and instrumented as described above (Instrumentation), instruct the subject to lie as still as possible.</li>
	<li>Once the subject has achieved a consistent resting state, continue to record at least 1 min of baseline data and then rapidly inflate a blood pressure cuff on the upper arm to a suprasystolic pressure (30 mmHg above systolic blood pressure).</li>
	<li>At the 5 min mark, rapidly deflate the cuff while recording the hyperemic response.</li>
	<li>Continue recording for at least 3 min to capture the subject's recovery.</li>
	<li>Calculating Reactive Hyperemia 
	NOTE: The NIRS parameters calculated are depicted in Figure 3.
	<ol>
		<li>Calculate baseline StO2 as the average StO2 over 1 full min prior to the onset of arterial cuff occlusion.</li>
		<li>Determine the resting skeletal muscle metabolic rate as the desaturation rate (i.e., average slope) during cuff occlusion (defined as Slope 1)27,28.</li>
		<li>Calculate reactive hyperemia as follows: 
		a) the average upslope following cuff release (i.e., reperfusion rate, defined as slope 2), calculated from the moment of cuff release through the linearly increasing phase of the rebound trace; 
		b) the highest StO2 value reached after cuff release (denoted as StO2max); 
		c) the reactive hyperemia area under the curve (AUC); calculated from the time of cuff release to 1-, 2- and 3-min post cuff-occlusion (AUC 1-min, AUC 2-min, and AUC 3-min, respectively); and 
		d) the hyperemic reserve, calculated as the change in StO2 above baseline and reported as a percent (%) change. This value is calculated as the highest saturation achieved during the post-occlusive rebound minus the average saturation calculated in step 3.5.1 (see above). 
		NOTE: Large differences in baseline data will greatly affect the interpretation of the hyperemic reserve.</li>
	</ol>
	</li>
</ol>
4. Functional Sympatholysis
NOTE: A representative data tracing illustrating the experimental procedure for measuring functional sympatholysis is depicted in Figure 4.
<ol>
	<li>Instrument the subject as indicated above (Instrumentation).</li>
	<li>Ensure an airtight seal in the LBNP chamber.</li>
	<li>With the subject lying still and at rest, collect 3 min of baseline data.</li>
	<li>At the 3 min mark, turn on the vacuum. Adjust the vacuum so that the pressure inside the LBNP chamber is between -20 and -30 mmHg. Allow the vacuum to run for 2 min while monitoring the subject's response.</li>
	<li>At the 5 min mark, turn off the vacuum and allow the subject to rest for 3 min.</li>
	<li>At the 8 min mark, initiate the voice prompt guiding the subject through the rhythmic hand grip exercise (20% MVC).</li>
	<li>Confirm that the subject is maintaining their squeeze throughout the entirety of each gripping phase and relaxing completely during between each repetition. Monitor their force output and confirm that they are achieving 20% MVC with each grip. Continue exercise until the 11 min mark.</li>
	<li>At the 11 min mark, turn on the vacuum encouraging the subject to continue their rhythmic exercise. Allow the vacuum to run from 11 - 13 min, then turn it off.</li>
	<li>Have the subject continue performing rhythmic hand grip exercise at 20% of their MVC for an additional 2 min. Upon exercise cessation, have the subject rest quietly and lie still.</li>
	<li>Calculating Functional Sympatholysis
	<ol>
		<li>Normalize the change in oxyhemoglobin with LBNP to the total labile signal (TLS), determined during 5 min cuff occlusion: 
		<img alt="Change in hemoglobin O2 formula, diagram for evaluating TLS in scientific experiment results." src="/files/ftp_upload/57317/57317eq2.jpg" data-altupdatedat="1788250015000" data-alt="Equation 2"> 
		<img alt="ΔHbO2 exercise equation for blood oxygenation analysis in physiological study diagram." src="/files/ftp_upload/57317/57317eq3.jpg" data-altupdatedat="1788250015000" data-alt="Equation 3"></li>
		<li>Calculate each event as the final 20 min average of each event.</li>
		<li>Calculate the exercise-induced attenuation of the oxyhemoglobin reduction: 
		<img alt="Hemo-globin variation formula, ΔHbO₂(rest) to ΔHbO₂(exercise), percentage calculation, equation." src="/files/ftp_upload/57317/57317eq4.jpg" data-altupdatedat="1788250015000" data-alt="Equation 4"></li>
	</ol>
	</li>
</ol>

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<li>Ryan, T. E., Brizendine, J. T., McCully, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+comparison+of+exercise+type+and+intensity+on+the+noninvasive+assessment+of+skeletal+muscle+mitochondrial+function+using+near-infrared+spectroscopy%5BTitle%5D)+AND+%22J+Appl+Physiol%22%5BJournal%5D)">A comparison of exercise type and intensity on the noninvasive assessment of skeletal muscle mitochondrial function using near-infrared spectroscopy.</a> J Appl Physiol. 114 (2), 230-237 (2013).</li>
<li>Adami, A., Cao, R., Porszasz, J., Casaburi, R., Rossiter, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Reproducibility+of+NIRS+assessment+of+muscle+oxidative+capacity+in+smokers+with+and+without+COPD%5BTitle%5D)+AND+%22Respir+Physiol+Neurobiol%22%5BJournal%5D)">Reproducibility of NIRS assessment of muscle oxidative capacity in smokers with and without COPD.</a> Respir Physiol Neurobiol. 235, 18-26 (2017).</li>
<li>Lacroix, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Reproducibility+of+near-infrared+spectroscopy+parameters+measured+during+brachial+artery+occlusion+and+reactive+hyperemia+in+healthy+men%5BTitle%5D)+AND+%22J+Biomed+Opt%22%5BJournal%5D)">Reproducibility of near-infrared spectroscopy parameters measured during brachial artery occlusion and reactive hyperemia in healthy men.</a> J Biomed Opt. 17 (7), 077010(2012).</li>
<li>Bopp, C. M., Townsend, D. K., Warren, S., Barstow, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Relationship+between+brachial+artery+blood+flow+and+total+%5Bhemoglobin%2Bmyoglobin%5D+during+post-occlusive+reactive+hyperemia%5BTitle%5D)+AND+%22Microvasc+Res%22%5BJournal%5D)">Relationship between brachial artery blood flow and total [hemoglobin+myoglobin] during post-occlusive reactive hyperemia.</a> Microvasc Res. 91, 37-43 (2014).</li>
<li>Willingham, T. B., Southern, W. M., McCully, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Measuring+reactive+hyperemia+in+the+lower+limb+using+near-infrared+spectroscopy%5BTitle%5D)+AND+%22J+Biomed+Opt%22%5BJournal%5D)">Measuring reactive hyperemia in the lower limb using near-infrared spectroscopy.</a> J Biomed Opt. 21 (9), 091302(2016).</li>
<li>Kragelj, R., Jarm, T., Erjavec, T., Presern-Strukelj, M., Miklavcic, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Parameters+of+postocclusive+reactive+hyperemia+measured+by+near+infrared+spectroscopy+in+patients+with+peripheral+vascular+disease+and+in+healthy+volunteers%5BTitle%5D)+AND+%22Ann+Biomed+Eng%22%5BJournal%5D)">Parameters of postocclusive reactive hyperemia measured by near infrared spectroscopy in patients with peripheral vascular disease and in healthy volunteers.</a> Ann Biomed Eng. 29 (4), 311-320 (2001).</li>
<li>Gurley, K., Shang, Y., Yu, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Noninvasive+optical+quantification+of+absolute+blood+flow%2C+blood+oxygenation%2C+and+oxygen+consumption+rate+in+exercising+skeletal+muscle%5BTitle%5D)+AND+%22J+Biomed+Opt%22%5BJournal%5D)">Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle.</a> J Biomed Opt. 17 (7), 075010(2012).</li>
</ol>

The authors declare that they have no competing financial interests.

The methods described herein enable non-invasive, clinical evaluation of reactive hyperemia, neurovascular coupling, and skeletal muscle oxidative capacity in a single clinic or laboratory visit.
Critical Considerations
Although NIRS is relatively robust and easy to use, collection of these data require careful placement of the optodes directly over the muscle belly, secured tightly in place to avoid movement artifact, and covered with a bl...

The hyperemic response to a brief period of tissue ischemia has emerged as a key non-invasive measure of (micro)vascular function. During occlusion of a conduit artery, downstream arterioles dilate in an effort to offset the ischemic insult. Upon release of the occlusion, the decreased vascular resistance results in hyperemia, the magnitude of which is dictated by one&#39;s ability to dilate the downstream microvasculature. While reactive hyperemia is a strong independent predictor of cardiovascular events1,2&#160;and therefore a clinically significant endpoint, its functional significance to exercise tolerance and quality of life is less clear.
Indeed, dynamic exercise represents a major cardiovascular stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic demand. For example, skeletal muscle blood flow can increase nearly 100-fold during isolated muscle contractions3, which would overwhelm the pumping capacity of the heart if such a hemodynamic response were extrapolated to whole-body exercise. Accordingly, to avoid severe hypotension, sympathetic (i.e., vasoconstrictor) nervous activity increases to redistribute cardiac output away from inactive and visceral tissues and towards active skeletal muscle4. Sympathetic outflow is also directed to the exercising skeletal muscle5; however, local metabolic signaling attenuates the vasoconstrictor response in order to ensure adequate tissue oxygen delivery6,7,8,9,10,11. Collectively, this process is termed functional sympatholysis12, and is imperative to the normal regulation of skeletal muscle blood flow during exercise. Since skeletal muscle blood flow is a key determinant of aerobic capacity &#8212; an independent predictor of quality of life and cardiovascular disease morbidity and mortality13&#8212; understanding the control of skeletal muscle blood flow and tissue oxygen delivery during exercise is of great clinical significance.
Oxygen delivery is only half of the Fick equation, however, with oxygen utilization satisfying the other half of the equation. Among the major determinates of oxygen utilization, mitochondrial oxidative phosphorylation plays an essential role in supplying adequate energy for cellular processes both at rest and during exercise. Indeed, impairments in muscle oxidative capacity can limit functional capacity and quality of life14,15,16. Various measures are commonly used to provide an index of muscle oxidative capacity, including invasive muscle biopsies and expensive and time-consuming magnetic resonance spectroscopy (MRS) techniques.
Here, we propose a novel, non-invasive approach, using near-infrared spectroscopy (NIRS), to assess each of these three major clinical endpoints (reactive hyperemia, sympatholysis, and muscle oxidative capacity) in a single clinic or laboratory visit. The major advantages of this approach are three-fold: First, this technique is easily portable, relatively low cost, and easy to perform. Current Doppler ultrasound approaches for measuring reactive hyperemia are highly operator-dependent &#8212; requiring extensive skill and training &#8212; and require sophisticated, high-cost, data acquisition hardware and post-processing software. Moreover, this could conceivably be introduced into the clinic and/or large clinical trials for bedside monitoring or testing therapeutic efficacy. Second, by virtue of the methodology, this technique focuses specifically on the skeletal muscle microvasculature, increasing the overall specificity of the technique. Alternative approaches using Doppler ultrasound focus entirely on upstream conduit vessels and infer changes downstream, which can dampen the signal. Third, this technique is completely non-invasive. Skeletal muscle oxidative capacity is traditionally assessed with invasive and painful muscle biopsies, and functional sympatholysis may be assessed with intra-arterial injection of sympathomimetics and sympatholytics. This approach avoids these requirements all together.

<table><tbody><tr><td>Dual-channel OxiplexTS Near-infrared spectroscopy machine</td><td>Iss Medical</td><td>101</td><td></td></tr><tr><td>NIRS muscle sensor</td><td>Iss Medical</td><td>201.2</td><td></td></tr><tr><td>E20 Rapid cuff inflation system</td><td>Hokanson</td><td>E20</td><td></td></tr><tr><td>AG101 Air Source</td><td>Hokanson</td><td>AG101</td><td></td></tr><tr><td>Smedley Handgrip dynometer (recording)</td><td>Stolting</td><td>56380</td><td></td></tr><tr><td>Powerlab 16/35, 16 Channel Recorder</td><td>ADInstruments</td><td>PL3516</td><td></td></tr><tr><td>Human NIBP Set</td><td>ADInstruments</td><td>ML282-SM</td><td></td></tr><tr><td>Bio Amp</td><td>ADInstruments</td><td>FE132</td><td></td></tr><tr><td>Quad Bridge Amp</td><td>ADInstruments</td><td>FE224</td><td></td></tr><tr><td>Connex Spot Monitor</td><td>Welch Allyn</td><td>71WX-B</td><td></td></tr><tr><td>Origin(Pro) graphing software</td><td>OrignPro</td><td>Pro</td><td></td></tr><tr><td>Lower body negative pressure chamber</td><td>Physiology Research Instruments</td><td>standard unit</td><td></td></tr></tbody></table>

skeletal muscle neurovascular coupling, oxidative capacity, and microvascular function with 'one stop shop' near-infrared spectroscopy

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic demand. Reactive hyperemia (in response to a brief period of tissue ischemia) is an independent predictor of cardiovascular events and provides important insight into vascular health and vasodilatory capacity. Skeletal muscle oxidative capacity is equally important in health and disease, as it determines the energy supply for myocellular processes. Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess each of these major clinical endpoints (reactive hyperemia, neurovascular coupling, and muscle oxidative capacity) during a single clinic or laboratory visit. Unlike Doppler ultrasound, magnetic resonance images/spectroscopy, or invasive catheter-based flow measurements or muscle biopsies, our approach is less operator-dependent, low-cost, and completely non-invasive. Representative data from our lab taken together with summary data from previously published literature illustrate the utility of each of these end-points. Once this technique is mastered, application to clinical populations will provide important mechanistic insight into exercise intolerance and cardiovascular dysfunction.

Skeletal muscle oxidative capacity
Figure 2 illustrates a representative participant response during a NIRS-derived skeletal muscle oxidative capacity assessment. Panel A shows the tissue saturation profile during a 5 min arterial cuff occlusion protocol, handgrip exercise, and intermittent arterial occlusion during recovery from exercise. Panel B illustrates the expected t...

Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess reactive hyperemia, neurovascular coupling and skeletal muscle oxidative capacity in a single clinic or laboratory visit.

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic ...

skeletal-muscle-neurovascular-coupling-oxidative-capacity

Research

JoVE Journal

Medicine

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In vivo Micro-circulation Measurement in Skeletal Muscle by Intra-vital Microscopy

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Functional Near Infrared Spectroscopy of the Sensory and Motor Brain Regions with Simultaneous Kinematic and EMG Monitoring During Motor Tasks

This work demonstrates the feasibility of an in vivo phosphorus-31 magnetic resonance spectroscopy (31PMRS) technique to quantify mitochondrial oxidative phosphorylation (OXPHOS) capacity in human skeletal muscle.

Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle

We describe a protocol to non-invasively and continuously measure absolute microvascular blood flow index and blood oxygen saturation using a multi-modal device based on near-infrared diffuse optics. We then evaluate the metabolic rate of oxygen consumption and reactive hyperemia utilizing a vascular occlusion test.

Non-Invasive Monitoring of Microvascular Oxygenation and Reactive Hyperemia using Hybrid, Near-Infrared Diffuse Optical Spectroscopy for Critical Care

Here, we describe a non-invasive approach using near-infrared spectroscopy to assess reactive hyperemia in the lower limb. This protocol provides a standardized assessment of vascular and microvascular responsiveness that may be used to determine the presence of vascular dysfunction as well as the efficacy of therapeutic interventions.

Near-Infrared Spectroscopy During Reactive Hyperemia for the Assessment of Lower Limb Vascular Function

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Myo-mechanical Analysis of Isolated Skeletal Muscle

We describe a minimally-invasive and painless method to measure canine hindlimb muscle strength and muscle response to repeated eccentric contractions.

In Vivo Canine Muscle Function Assay

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Skeletal Muscle Gender Dimorphism from Proteomics

Capillaroscopy is a non-invasive, relatively inexpensive methodology for directly visualizing the microcirculation. The forearm blood flow technique provides accepted non-invasive measures of endothelial function.

Non-invasive Assessment of Microvascular and Endothelial Function

Learn to noninvasively assess skeletal muscle oxidative capacity, reactive hyperemia, and neurovascular coupling using near-infrared spectroscopy. This method enables comprehensive evaluation of macro and microvascular function in clinical settings.

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with One Stop Shop Near-infrared Spectroscopy (Video) | JoVE Journal

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy

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