Cycling Power vs. Muscle Oxygenation and Nitric Oxide

I was recently asked about the relationship between peak power, change in muscle oxygenation (ΔSmO2), and peak nitric oxide levels across the population. Ie, does a larger ΔSmO2 or higher Peak NO correlate with a higher absolute power output across a diverse group of athletes?

Up to this point, we’ve collected a wealth of data showing that as a given athlete increases their peak power output (or max sprint speed) over time, they are able to elicit a greater change in SmO2 (ΔSmO2) from their baseline during exercise. However, we previously had limited data comparing these factors across a large population.

To answer the question above, I gathered NNOXX biomarker data from 45 participants of varying ages and genders (roughly 25–70 years old). These participants all performed unstructured cycling exercise in the form of a Fartlek ride, and I recorded their peak acceleration, ΔSmO2max (largest change in SmO2 from baseline), and NOpeak (highest recorded NO level). Here’s what we found:

Figure 1 (left) above shows that non-invasive optically-derived deoxygenation rates are strongly correlated with peak acceleration during unstructured cycling exercise in healthy subjects (n=45, r = 0.71, p = 0.02). *Both SmO2 and acceleration measured via NNOXX

Figure 2 (right) shows that non-invasive optically-derived NO measurements are strongly correlated with peak acceleration during unstructured running exercise in healthy subjects (n=45, r = 0.79, p = 0.03).

My takeaway from this analysis, is that a larger ΔSmO2 from baseline and higher peak NO levels are associated with greater peak acceleration, and subsequently power during cycling exercise. Going forward, we’ll begin to tease out causes and effects, test these relationships across other exercise modalities, and see how we can use this power:SmO2 and power:NO profiles to more easily identify physiological limitations.

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