Abstract
AbstractThe blood lactate threshold (LT) is a crucial marker of metabolic shifts and stress transitions during exercise, influencing optimal intensity determination and chronic exercise impact evaluation across diverse individuals. Although recent studies have explored methods for estimating blood lactate levels without blood sampling, accurate solutions for LT estimation remain undeveloped. Here, we tested the analytical capability of an ultra-minimally invasive technique for LT measurement that harnesses skin interstitial lactate dynamics using a single microneedle perfusion system. The rats were acclimated to exercise and underwent external jugular vein cannulation. Following comprehensive recovery, a 1 mm single microneedle was implanted into the back skin. This allowed for the simultaneous measurement of lactate concentrations in the blood and skin interstitial fluid during incremental treadmill exercise. Skin lactate progressively increased in tandem with blood lactate during incremental exercise, albeit with lingering post-exercise clearance that did not correlate with blood lactate. Remarkably, LT extrapolated from skin lactate showed significant alignment with blood LT. Our findings reveal the potential of skin interstitial dynamics to accurately assess LT during exercise using a single microneedle, integrating the discoveries of exercise physiology into real-world athletic and/or healthy practices.
Publisher
Cold Spring Harbor Laboratory