Effects of water intake on composition of thermal sweat in normal human volunteers

Cage, Gary W.; Wolfe, S. M.; Thompson, Ronald G.; Gordon, Rebecca

doi:10.1152/jappl.1970.29.5.687

Cited by 17 publications

(6 citation statements)

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“…However, lactate concentration becomes relatively stable after 1,100 s, indicating the stabilization of physiological responses to continuous, sub-maximal constant-exercise power output 22 . Sweat [Na + ] increases and [K + ] decreases in the beginning of perspiration, in line with the previous ex situ studies from the collected sweat samples 28,29 . Both [Na + ] and [K + ] stabilize as the cycling continues.…”

Section: Letter Researchsupporting

confidence: 91%

Wearable physiological systems and technologies for metabolic monitoring

Gao

Brooks

Klonoff

2018

Journal of Applied Physiology

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Wearable sensors allow continuous monitoring of metabolites for diabetes, sports medicine, exercise science, and physiology research. These sensors can continuously detect target analytes in skin interstitial fluid (ISF), tears, saliva, and sweat. In this review, we will summarize developments on wearable devices and their potential applications in research, clinical practice, and recreational and sporting activities. Sampling skin ISF can require insertion of a needle into the skin, whereas sweat, tears, and saliva can be sampled by devices worn outside the body. The most widely sampled metabolite from a wearable device is glucose in skin ISF for monitoring diabetes patients. Continuous ISF glucose monitoring allows estimation of the glucose concentration in blood without the pain, inconvenience, and blood waste of fingerstick capillary blood glucose testing. This tool is currently used by diabetes patients to provide information for dosing insulin and determining a diet and exercise plan. Similar technologies for measuring concentrations of other analytes in skin ISF could be used to monitor athletes, emergency responders, warfighters, and others in states of extreme physiological stress. Sweat is a potentially useful substrate for sampling analytes for metabolic monitoring during exercise. Lactate, sodium, potassium, and hydrogen ions can be measured in sweat. Tools for converting the concentrations of these analytes sampled from sweat, tears, and saliva into blood concentrations are being developed. As an understanding of the relationships between the concentrations of analytes in blood and easily sampled body fluid increases, then the benefits of new wearable devices for metabolic monitoring will also increase.

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Section: Letter Researchsupporting

confidence: 91%

Wearable physiological systems and technologies for metabolic monitoring

Gao

Brooks

Klonoff

2018

Journal of Applied Physiology

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supporting

confidence: 91%

Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis

Gao

Emaminejad

Nyein

et al. 2016

Nature

3,949

3,259

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Wearable sensor technologies are essential to the realization of personalized medicine through continuously monitoring an individual's state of health1–12. Sampling human sweat, which is rich in physiological information13, could enable non-invasive monitoring. Previously reported sweat-based and other non-invasive biosensors either can only monitor a single analyte at a time or lack on-site signal processing circuitry and sensor calibration mechanisms for accurate analysis of the physiological state14–18. Given the complexity of sweat secretion, simultaneous and multiplexed screening of target biomarkers is critical and requires full system integration to ensure the accuracy of measurements. Here we present a mechanically flexible and fully integrated (that is, no external analysis is needed) sensor array for multiplexed in situ perspiration analysis, which simultaneously and selectively measures sweat metabolites (such as glucose and lactate) and electrolytes (such as sodium and potassium ions), as well as the skin temperature (to calibrate the response of the sensors). Our work bridges the technological gap between signal transduction, conditioning (amplification and filtering), processing and wireless transmission in wearable biosensors by merging plastic-based sensors that interface with the skin with silicon integrated circuits consolidated on a flexible circuit board for complex signal processing. This application could not have been realized using either of these technologies alone owing to their respective inherent limitations. The wearable system is used to measure the detailed sweat profile of human subjects engaged in prolonged indoor and outdoor physical activities, and to make a real-time assessment of the physiological state of the subjects. This platform enables a wide range of personalized diagnostic and physiological monitoring applications.

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“…Acute/ Chronic No effect on sweat mineral or vitamin concentrations [230,231,[248][249][250] Fluid intake Acute Water ingestion results in a reflex (oropharyngeal) transient increase in RSR, especially when in a hypohydrated state [360,361]; no effect on sweat Na, K, Cl, and lactate concentrations [361] Dehydration Acute Reduced WBSR and RSR attributed to hyperosmolality-induced increase in threshold for sweat onset and to a lesser extent by a hypovolemia-induced decrease in sweat sensitivity (see Figure 3) [42,[76][77][78]80,82]; equivocal effects on sweat [Na] and [Cl] [134,153,[190][191][192][193][194][195]; no effect on sweat [K] [190] Alcohol Acute No effect on sweating rate [331,332]; sweat ethanol concentration increases with ethanol ingestion and rises linearly with increases in blood alcohol concentration [334,335] Exercise Intensity Acute Increase in WBSR and RSR with increases in exercise intensity [104,362] as metabolic heat production is directly proportional to energy expenditure [201,203]; sweat [Na] and [Cl] increase with increases in exercise intensity because the relative rate of Na and Cl reabsorption is flow dependent [39,159], minimal or no effect on sweat [K] [159], inverse relation between sweating rate and sweat lactate [162] and ammonia concentrations [6,…”

Section: Modifiers Of Eccrine Sweatingmentioning

confidence: 99%

Physiology of sweat gland function: The roles of sweating and sweat composition in human health

2019

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The purpose of this comprehensive review is to: 1) review the physiology of sweat gland function and mechanisms determining the amount and composition of sweat excreted onto the skin surface; 2) provide an overview of the well-established thermoregulatory functions and adaptive responses of the sweat gland; and 3) discuss the state of evidence for potential non-thermoregulatory roles of sweat in the maintenance and/or perturbation of human health. The role of sweating to eliminate waste products and toxicants seems to be minor compared with other avenues of excretion via the kidneys and gastrointestinal tract; as eccrine glands do not adapt to increase excretion rates either via concentrating sweat or increasing overall sweating rate. Studies suggesting a larger role of sweat glands in clearing waste products or toxicants from the body may be an artifact of methodological issues rather than evidence for selective transport. Furthermore, unlike the renal system, it seems that sweat glands do not conserve water loss or concentrate sweat fluid through vasopressin-mediated water reabsorption. Individuals with high NaCl concentrations in sweat (e.g. cystic fibrosis) have an increased risk of NaCl imbalances during prolonged periods of heavy sweating; however, sweat-induced deficiencies appear to be of minimal risk for trace minerals and vitamins. Additional research is needed to elucidate the potential role of eccrine sweating in skin hydration and microbial defense. Finally, the utility of sweat composition as a biomarker for human physiology is currently limited; as more research is needed to determine potential relations between sweat and blood solute concentrations.

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Effects of water intake on composition of thermal sweat in normal human volunteers

Cited by 17 publications

References 0 publications

Wearable physiological systems and technologies for metabolic monitoring

Wearable physiological systems and technologies for metabolic monitoring

Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis

Physiology of sweat gland function: The roles of sweating and sweat composition in human health

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