scholarly journals Optimizing the Measurement of Skin Wettedness in Exercising Humans

2019 ◽  
Vol 33 (S1) ◽  
Author(s):  
Jessica L Hichez ◽  
Nicole T Vargas ◽  
Zachary J Schlader
Keyword(s):  
Skin Wettedness

scholarly journals Monitoring Transepidermal Water Loss and Skin Wettedness Factor with Battery-Free NFC Sensor

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5549
Author(s):  
Syed Muhammad Ali ◽  
Wan-Young Chung
Keyword(s):  
Water Loss ◽  
Near Field ◽  
Experimental Tests ◽  
Transepidermal Water Loss ◽  
Comfort Level ◽  
Skin Wettedness ◽  
Moisture Content Level ◽  
Indoor And Outdoor Environments ◽  
Skin Moisture

The transepidermal water loss (TEWL) and the skin wettedness factor (SWF) are considered parts of a key perspective related to skincare. The former is used to determine the loss of water content from the stratum corneum (SC), while the latter is used to determine the human skin comfort level. Herein, we developed two novel approaches: (1) determination of the TEWL and the SWF based on a battery-free humidity sensor, and (2) the design of a battery-free smart skincare sensor device tag that can harvest energy from a near field communication (NFC)-enabled smartphone, making it a battery-free design approach. The designed skincare device tag has a diameter of 2.6 cm and could harvest energy (~3 V) from the NFC-enabled smartphone. A series of experimental tests involving the participation of eight and six subjects were conducted in vivo for the indoor and outdoor environments, respectively. During the experimental analysis, the skin moisture content level was measured at different times of the day using an android smartphone. The TEWL and SWF values were calculated based on these sensor readings. For the TEWL case: if the skin moisture is high, the TEWL is high, and if the skin moisture is low, the TEWL is low, ensuring that the skin moisture and the TEWL follow the same trend. Our smart skincare device is enclosed in a 3D flexible design print, and it is battery-free with an android application interface that is more convenient to carry outside than other commercially available battery-based devices.

Maximum Skin Wettedness after Aerobic Training with and without Heat Acclimation

2018 ◽  
Vol 50 (2) ◽  
pp. 299-307 ◽  
Author(s):  
NICHOLAS RAVANELLI ◽  
GEOFF B. COOMBS ◽  
PASCAL IMBEAULT ◽  
OLLIE JAY
Keyword(s):  
Aerobic Training ◽  
Heat Acclimation ◽  
Skin Wettedness

Evaluation of vapor permeation through garments during exercise

1985 ◽  
Vol 58 (3) ◽  
pp. 928-935 ◽  
Author(s):  
R. R. Gonzalez ◽  
K. Cena
Keyword(s):  
Heat Loss ◽  
Cycle Ergometer ◽  
Dew Point ◽  
Evaporative Heat Loss ◽  
Local Skin ◽  
Vapor Permeation ◽  
Skin Wettedness ◽  
Latent Heat Loss ◽  
Saturation Vapor ◽  
Practical Dimension

Five males [age 28 +/- 8 yr; maximum O2 uptake (VO2max) 50 +/- 6 ml O2 . kg-1 . min-1; body wt 70 +/- 3 kg; DuBois surface area 1.85 +/- 0.02 m2] exercised on a cycle ergometer, placed on a Potter scale, at 31% VO2max for up to 2 h at an ambient temperature (Ta) of 25 degrees C and a dew-point temperature of 15 degrees C. Air movement was varied from still air to 0.4 and 2 m/s. Each subject, in separate runs, wore a track suit (TS ensemble) of 60% polyester-40% cotton (effective clo = 0.5); a Gortex parka (GOR ensemble), covering a sweat shirt and bottom of TS (effective clo = 1.4); or the TS ensemble covered by polyethylene overgarment (POG ensemble). Esophageal, skin temperature (Tsk) at eight sites, and heart rate were continuously recorded. Dew-point sensors recorded temperatures under the garments at ambient and chest (windward site) and midscapular sites. Local skin wettedness (loc w) and ratio of evaporative heat loss (Esk) to maximum evaporative capacity were determined. An observed average effective permeation (Pe, W . m-2 . Torr-1) was calculated as Esk/loc w (Ps,sk - Pw), where w is the average of chest and back loc w and (Ps,sk - Pw) is the gradient of skin saturation vapor pressure at Tsk and Ta. Additionally, the local effective evaporative coefficient was determined for chest and back sites by Esk/(Ps,dpl - Pw). The GOR ensemble produced an almost as high a Pe as the TS ensemble (82–86% of Pe with TS in still air and 0.4- and 2-m/s conditions). Direct dew-point recording offers an easy practical dimension to the study of efficacy of latent heat loss and skin wettedness properties through garments.

Influence of air velocity and heat acclimation on human skin wettedness and sweating efficiency

1979 ◽  
Vol 47 (6) ◽  
pp. 1194-1200 ◽  
Author(s):  
V. Candas ◽  
J. P. Libert ◽  
J. J. Vogt
Keyword(s):  
Sweat Rate ◽  
Water Vapor Pressure ◽  
Thermal Conditions ◽  
Heat Acclimation ◽  
Air Velocity ◽  
Experimental Conditions ◽  
Wind Speeds ◽  
Skin Wettedness ◽  
Before And After ◽  
Sweating Efficiency

Before and after heat acclimation, four male resting subjects were exposed to humid heat that caused levels of skin wettedness ranging from 50 to 100%. The physical experimental conditions were chosen so that the same skin wettedness was attained with modification of only the ambient water vapor pressure, at two wind speeds (0.6 and 0.9 m . s-1). The esophageal temperature (Tes), mean skin temperature (Tsk), sweating rate (msw), and dripping sweat rate (mdr) were recorded; the amounts of local drippage in the same thermal conditions before and after acclimation were also determined. The relationship between the evaporative efficiency of sweating (eta sw) and the skin wettedness (w) is reported, as is the influence of the subject's acclimation to humid heat on adjustments of skin wettedness. The effects of the air velocity on the coefficient of evaporation and on sweating efficiency are discussed. Beneficial increases in evaporation were achievable by increasing skin wettedness only when there was a consistent drippage, which differed from one body area to another and from one subject to another. The relation of drift in body temperature to skin wettedness changed with the acclimation of the subjects.

Human skin wettedness and evaporative efficiency of sweating

1979 ◽  
Vol 46 (3) ◽  
pp. 522-528 ◽  
Author(s):  
V. Candas ◽  
J. P. Libert ◽  
J. J. Vogt
Keyword(s):  
Sweat Rate ◽  
The Body ◽  
Body Temperatures ◽  
Skin Wettedness ◽  
Evaporative Heat Transfer ◽  
Evaporative Heat Transfer Coefficient ◽  
The Relationship ◽  
Male Subjects ◽  
Skin Temperatures ◽  
Different Levels

Rates of evaporation and sweating were recorded for three acclimatized male subjects in hot humid conditions, the ambient parameters of which were set so that the various imposed evaporative rates required the same skin wettedness at different levels of sweating. Rectal and skin temperatures were measured. Results showed that during steady state occurring during the 2nd h of exposure each subject reached the required evaporative rate by means of increases in skin wettedness regardless of the level of sweating; the sweat evaporative efficiency, defined as the ratio between evaporative rate and sweat rate, decreased as skin wettedness increased, in a range between 0.74 and 1.0 Sweat efficiency fell to 0.67 for fully wet skin. The body temperatures did not increase with time if skin wettedness was less than unity. Evaporative heat transfer coefficient (he), maximum evaporative capacity, and wettedness were estimated on the basis of the observed decrease of sweat efficiency. The relationship between skin wettedness and sweat efficiency was interpreted as a combined effect of differences in local he as well as in local sweat rates.

scholarly journals Skin wettedness is an important contributor to thermal behavior during exercise and recovery

2018 ◽  
Vol 315 (5) ◽  
pp. R925-R933 ◽  
Author(s):  
Nicole T. Vargas ◽  
Christopher L. Chapman ◽  
Blair D. Johnson ◽  
Rob Gathercole ◽  
Zachary J. Schlader
Keyword(s):  
Linear Regression ◽  
Thermal Behavior ◽  
Skin Temperature ◽  
Mean Skin Temperature ◽  
Independent Variables ◽  
Skin Wettedness ◽  
Custom Made ◽  
Individual Minute ◽  
Neck Temperature ◽  
Skin Temperatures

We tested the hypothesis that mean skin wettedness contributes to thermal behavior to a greater extent than core and mean skin temperatures. In a 27.0 ± 1.0°C environment, 16 young participants (8 females) cycled for 30 min at 281 ± 51 W·m2, followed by 120 min of seated recovery. Mean skin and core temperatures and mean skin wettedness were recorded continuously. Participants maintained a thermally comfortable neck temperature throughout the protocol using a custom-made device. Neck device temperature provided an index of thermal behavior. Linear regression was performed using individual minute data with mean skin wettedness and core and mean skin temperatures as independent variables and neck device temperature as the dependent variable. Standarized β-coefficients were used to determine relative contributions to thermal behavior. Mean skin temperature differed from preexercise (32.6 ± 0.5°C) to 10 min into exercise (32.3 ± 0.6°C, P < 0.01). Core temperature increased from 37.1 ± 0.3°C preexercise to 37.7 ± 0.4°C by end exercise ( P < 0.01) and remained elevated through 30 min of recovery (37.2 ± 0.3°C, P < 0.01). Mean skin wettedness increased from preexercise [0.14 ± 0.03 arbitrary units (AU)] to 20 min into exercise (0.43 ± 0.09 AU, P < 0.01) and remained elevated through 80 min of recovery (0.18 ± 0.06 AU, P ≤ 0.05). Neck device temperature decreased from 26.4 ± 1.6°C preexercise to 18.5 ± 8.7°C 10 min into exercise ( P = 0.03) and remained depressed through 20 min of recovery (14.4 ± 11.2°C, P < 0.01). Mean skin wettedness (52 ± 24%) provided a greater contribution to thermal behavior compared with core (22 ± 22%, P = 0.06) and mean skin (26 ± 16%, P = 0.04) temperatures. Skin wettedness is an important contributing factor to thermal behavior during exercise and recovery.

scholarly journals Exercise intensity independently modulates thermal behavior during exercise recovery but not during exercise

2019 ◽  
Vol 126 (4) ◽  
pp. 1150-1159 ◽  
Author(s):  
Nicole T. Vargas ◽  
Christopher L. Chapman ◽  
Blair D. Johnson ◽  
Rob Gathercole ◽  
Zachary J. Schlader
Keyword(s):  
Thermal Behavior ◽  
Exercise Intensity ◽  
High Intensity ◽  
Weighted Average ◽  
High Intensity Exercise ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Afferent Stimulus ◽  
Skin Wettedness ◽  
Custom Made

We tested the hypothesis that thermal behavior is greater during and after high- compared with moderate-intensity exercise. In a 27°C, 20% relative humidity environment, 20 participants (10 women, 10 men) cycled for 30 min at moderate [53% (SD 6) peak oxygen uptake (V̇o2peak) or high [78% (SD 6) V̇o2peak] intensity, followed by 120 min of recovery. Mean skin and core temperatures and mean skin wettedness were recorded continuously. Participants maintained thermally comfortable neck temperatures with a custom-made neck device. Neck device temperature provided an index of thermal behavior. The weighted average of mean skin and core temperatures and mean skin wettedness provided an indication of the afferent stimulus to thermally behave. Mean skin and core temperatures were greater at end-exercise in high intensity ( P < 0.01). Core temperature remained elevated in high intensity until 70 min of recovery ( P = 0.03). Mean skin wettedness and the afferent stimulus were greater at 10–20 min of exercise in high intensity ( P ≤ 0.03) and remained elevated until 60 min of recovery ( P < 0.01). Neck device temperature was lower during exercise in high versus moderate intensity ( P ≤ 0.02). There was a strong relation between the afferent stimulus and neck device temperature during exercise (high: R2 = 0.82, P < 0.01; moderate: R2 = 0.95, P < 0.01) and recovery (high: R2 = 0.97, P < 0.01; moderate: R2 = 0.93, P < 0.01). During exercise, slope ( P = 0.49) and y-intercept ( P = 0.91) did not differ between intensities. In contrast, slope was steeper ( P < 0.01) and y-intercept was higher ( P < 0.01) during recovery from high-intensity exercise. Thermal behavior is greater during high-intensity exercise because of the greater stimulus to behave. The withdrawal of thermal behavior is augmented after high-intensity exercise. NEW & NOTEWORTHY This is the first study to determine the effects of exercise intensity on thermal behavior. We show that exercise intensity does not independently modulate thermal behavior during exercise but is dependent on the magnitude of afferent stimuli. In contrast, the withdrawal of thermal behavior after high-intensity exercise is augmented. This may be a consequence of an attenuated perceptual response to afferent stimuli, which may be due to processes underlying postexercise hypoalgesia.

Indices of thermoregulatory strain for moderate exercise in the heat

1978 ◽  
Vol 44 (6) ◽  
pp. 889-899 ◽  
Author(s):  
R. R. Gonzalez ◽  
L. G. Berglund ◽  
A. P. Gagge
Keyword(s):  
Water Vapor Pressure ◽  
Heat Acclimation ◽  
Skin Surface ◽  
Normal Male ◽  
Evaporative Heat Loss ◽  
Physiological Strain ◽  
Test Environment ◽  
Mean Body Temperature ◽  
Air Movement ◽  
Skin Wettedness

The effect of varying humidity and dry bulb temperatures was studied on five normal male unclothed subjects while exercising (40–45 min) at 28% VO2max. Air movement was 0.75 m.s-1. The initial test and the 16th test on each subject both done at 50 degrees C and 30 Torr (32% rh). Each subject did the intervening 14 experiments twice per day at varying ambient temperature (Ta) and water vapor pressure (Pa) levels, so selected to progressively increase skin wettedness levels. Mean skin temperature (Tsk) and esophageal temperature (Tes), heart rate (HR), skin evaporative heat loss (Esk), and warm discomfort were continuously observed. Skin wettedness (w) was evaluated as the ratio of the observed Esk to the maximum evaporative capacity of the environment. A rational effective temperature (ET) is defined as the dry bulb temperature at 50% rh in which the total heat exchange from skin surface would be the same as in the test environment, described by the observed Ta and Pa. The results showed that 1) during steady state both HR and Tes were unaffected by Ta from 26 to 41 degrees C responding to the level of exercise intensity, when Pa less than or equal to 20 Torr; 2) both mean body temperature, found by weighting Tsk:Tes by 1:9, and ET were each significant indicators of physiological strain when Pa greater than 20 Torr; 3) a level of strain, caused by skin wettedness values greater than 0.5, is suggested as a primary condition necessary for inducing heat acclimation.

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