Skin sympathetic nerve activity: Potential new non‐invasive indicator of exercise metabolic thresholds in adults

Figures

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  FIGURE 1. Device Connections. The three curves connected to the participants' torso represent the SKNA lead lines, which are linked to the bioelectric acquisition system interfaced with a computer. The curve connected to the respiratory mask represents the VO2 acquisition line, which is also connected to the computer. Figure created in https://BioRender.com.

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  FIGURE 2. (a) A segment of the raw SKNA recording. (b) Trends in aSKNA changes in a participant's experiment. Due to variations in exercise duration, only one participant was selected to represent the complete curve as an example.

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  FIGURE 3. Trends and correlations in aSKNA, VO2, and HR during exercise. (a) Trend profiles in aSKNA, VO2, and HR during RIET. (b) Correlation analysis results for aSKNA with VO2 and HR.

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  FIGURE 4. Localization of SKNATs. SKNAT‐sub refers to the inflection point identified through the visual judgment method, SKNATs‐obj refers to the inflection point determined using the dynamic programming algorithm. (a) The inflection point identified via the visual judgment method. (b) The inflection point determined through the dynamic programming algorithm. (c) The overlap of the two methods. (d) The SKNAT identified by the dynamic programming algorithm.

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  FIGURE 5. Variation in SKNATs versus VTs.

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  FIGURE 6. Correlations in SKNATs and VTs. r > 0.6 is considered indicative of a strong correlation.

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  FIGURE 7. Bland–Altman plot of SKNATs versus VTs. The dashed lines at the top and bottom of the figure represent the mean difference between the measurements of the two methods, while the dashed line in the middle indicates the 95% limits of agreement (+1.96 SD and −1.96 SD). The points on the figure represent the differences between the measured values of individual samples and the mean value. Ideally, most of these points should fall within the 95% limits of agreement.