Implications of the Onset of Sweating on the Sweat Lactate Threshold

Maeda, Yuta; Okawara, Hiroki; Sawada, Tomio; Nakashima, Daisuke; Nagahara, Joji; Fujitsuka, Haruki; Ikeda, Kaito; Hoshino, Sosuke; Kobari, Yusuke; Katsumata, Yoshinori; Nakamura, Masaya; Nagura, Takeo

doi:10.3390/s23073378

Cited by 10 publications

(2 citation statements)

References 42 publications

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“…After calibration using saline for 2 or 3 min, the sensor chip connected to the sensor device was attached to the superior right upper limb of the participant 13 , 14 , which was cleaned with an alcohol-free cloth. The upper arm has a high-sweat rate during physical excursions 33 .…”

Section: Methodsmentioning

confidence: 99%

Estimation of maximal lactate steady state using the sweat lactate sensor

Muramoto,

Nakashima,

Amano

et al. 2023

Sci Rep

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A simple, non-invasive algorithm for maximal lactate steady state (MLSS) assessment has not been developed. We examined whether MLSS can be estimated from the sweat lactate threshold (sLT) using a novel sweat lactate sensor for healthy adults, with consideration of their exercise habits. Fifteen adults representing diverse fitness levels were recruited. Participants with/without exercise habits were defined as trained/untrained, respectively. Constant-load testing for 30 min at 110%, 115%, 120%, and 125% of sLT intensity was performed to determine MLSS. The tissue oxygenation index (TOI) of the thigh was also monitored. MLSS was not fully estimated from sLT, with 110%, 115%, 120%, and 125% of sLT in one, four, three, and seven participants, respectively. The MLSS based on sLT was higher in the trained group as compared to the untrained group. A total of 80% of trained participants had an MLSS of 120% or higher, while 75% of untrained participants had an MLSS of 115% or lower based on sLT. Furthermore, compared to untrained participants, trained participants continued constant-load exercise even if their TOI decreased below the resting baseline (P < 0.01). MLSS was successfully estimated using sLT, with 120% or more in trained participants and 115% or less in untrained participants. This suggests that trained individuals can continue exercising despite decreases in oxygen saturation in lower extremity skeletal muscles.

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Section: Methodsmentioning

confidence: 99%

Estimation of maximal lactate steady state using the sweat lactate sensor

Muramoto,

Nakashima,

Amano

et al. 2023

Sci Rep

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“…Seki et al confirmed that LT calculated from sweat lactate levels during exercise was significantly associated with LT derived from blood lactate concentrations 9 . However, the same research group also reported that there were some cases in which sweat LT failed to align with blood LT, attributable to individual variations in sweat patterns 10 . Moreover, the evaluation of sweat lactate cannot be performed in scenarios where exercise occurs in cold environments, during swimming activities, or in low-intensity workouts, where sweat production is minimal or infrequent.…”

Section: Introductionmentioning

confidence: 97%

Exercise intensity-dependent lactate elevation in skin interstitial fluid and its long-lasting effect

Dobashi,

Funabashi,

Sameshima

et al. 2023

Preprint

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The 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.Graphical abstractRepresentative graphical image of exercise rats with inserted an ultra-minimally invasive single microneedle (A). Representative graph of LT assessed by the blood (B) and skin fluid lactate (C) dynamics. The findings suggest that LT determination using the perfusate collected by the single microneedle perfusion system can be an effective alternative to current methods for measuring blood lactate, which may be a breakthrough in the development of sports science.

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