Sweat Distribution Research Articles

Preparation of hygroscopic fabric with a uniform and slow exothermic effect and its thermoregulation evaluation

Hygroscopic-exothermic textiles dissipate heat by absorbing moisture around the skin, which makes humans feel warm in a cold environment. However, the local rapid temperature rising and heat concentration due to uneven sweat distribution can cause a heat sensation that is unfavorable to personal thermal comfort in a relatively short period of time. Herein, hygroscopic fabric with a uniform and slow exothermic effect was prepared to achieve thermal-wet comfort of garments. The hierarchical structure textile consists of an inner layer with moisture diffusion and transport performance, a middle layer with moisture absorption and storage properties and an outer layer with moisture absorption and heat generation characteristics, which achieved the effect of slow and uniform heat dissipation during the moisture absorption by controlling the moisture transmission within the fabric. Based on the study of the uniform and slow exothermic effect of fabrics, five indexes, namely the average temperature value, the maximum temperature value, the temperature distribution uniformity index, the percentage of the heating area distribution at the maximum temperature point on the fabric surface and the initial heating rate, were proposed to evaluate the uniformity and the slowness of moisture absorption and heat dissipation in textiles. The result showed that the initial heating rate of multi-layer fabric could be reduced by 0.11–0.25°C/min compared to the single-layer hygroscopic-exothermic fabric and there was an up to 29.93% increase in the heat dissipation area at the maximum temperature point. The uniformity of temperature distribution after moisture absorption of fabrics increased by 41.6–58%.

Single-Sided Jacquard Knit Fabric Development and Seamless Ski Underwear Zoning Design based on Body Mapping Sportswear

Abstract In order to meet the functional requirements of professional skiers for ski underwear, such as warmth, breathability, moisture absorption, sweat drainage, and stretch elasticity, six single-sided jacquard knit fabric structures were designed and then knitted with polyester and DRYARN. Then, 12 fabrics were acquired and ranked comprehensively by the one-way analysis of variance and grey correlative analysis based on entropy. According to the fabric properties and sweat distribution on the human skin surface, the professional ski underwear was zoning designed and the wearing experiment and evaluation were carried out on the “Newton” sweated manikin system. The analysis results show that the fabric with DRYARN® material has better air permeability and moisture permeability. Thermal resistance, Clo value, and permeability play important roles in comprehensive evaluation. The results of wearing experiment show that the seamless professional ski underwear woven based on body mapping sportswear has superior function and reasonable design, which can provide technical support for the design of professional seamless ski underwear.

Dynamic of upper body sweat distribution in young males wearing fully encapsulated chemical protective ensembles

Impermeability is a feature of fully encapsulated chemical protective ensembles (FCPE), which can affect people's sweat and affect their clothing's thermal-wet comfort. This study investigated the dynamics of upper-body sweat distribution in young males wearing FCPE and explored variations in sweat rate intra-region and inter-time for 10 young and healthy male college students. The study was carried in a climatic chamber (environment temperature 35 °C, relative humidity 60%) with participants exercising on a treadmill at 4 km/h, 5%. Sweat was collected using a 35-pad set of absorbent pads that were changed every 5 min during the course of the experiment. A total of 7-pad sets were collected with an average sweat rate of 389, 631, 920, 1137, 1100, 1211, and 1105 g m−2 h−1, respectively. The medial upper back, lateral lower back, medial upper chest, medial mid-back, and lateral top back had the highest sweat rates, with average values of 1406, 1278, 1198, 1181 and 1139 g m−2 h−1, respectively. The waist (with average values of 557, 370, 596, and 332 g m−2 h−1, respectively) and bottom zones (373, 398, 661, and 849 g m−2 h−1, respectively) had the lowest sweat rates. The above data showed that the role of FCPE in promoting body perspiration. The upper body may be split into three zones of sweat rates based on the distribution result allowing for the design of more comfortable clothing. The study includes the fundamental physiological data as well as the design recommendations for advanced personal protective equipment.

Body mapping of sweating patterns of pre-pubertal children during intermittent exercise in a warm environment

PurposeTo determine sweating responses of pre-pubertal children during intermittent exercise in a warm environment and create whole-body maps of regional sweat rate (RSRs) distribution across the body.MethodsThirteen pre-pubertal children; six girls and seven boys (8.1 ± 0.8 years) took part. Sweat was collected using the technical absorbent method in the last 5 min of a 30-min intermittent exercise protocol performed at 30 ℃, 40% relative humidity and 2 m·s−1 frontal wind.ResultsMean gross sweat loss (GSL) was 126 ± 47 g·m−2·h−1 and metabolic heat production was 278 ± 50 W·m2. The lower anterior torso area had the lowest RSR with a median (IQR) sweat rate (SR) of 40 (32) g·m−2·h−1. The highest was the forehead with a median SR of 255 (163) g·m−2·h−1. Normalised sweat maps (the ratio of each region’s SR to the mean SR for all measured pad regions) showed girls displayed lower ratio values at the anterior and posterior torso, and higher ratios at the hands, feet and forehead compared to boys. Absolute SRs were similar at hands and feet, but girls sweated less in most other areas, even after correction for metabolic rate.ConclusionPre-pubertal children have different RSRs across the body, also showing sex differences in sweat distribution. Distributions differ from adults. Hands and feet RSR remain stable, but SR across other body areas increase with maturation. These data can increase specificity of models of human thermoregulation, improve the measurement accuracy of child-sized thermal manikins, and aid companies during product design and communication.

The use of 33 MHz ultra-high-frequency ultrasonography for the evaluation of sweat glands in the axilla with osmidrosis.

BackgroundThis study aimed to assess the use of 33 MHz ultra-high-frequency ultrasonography (33MHz-UHFUS) for evaluating axillary sweat glands with osmidrosis in comparison with histological techniques. Axillary osmidrosis is a common problem in Asian societies, and the number and size of apocrine sweat glands have a strong relationship with osmidrosis severity. Currently, there are no methods to evaluate sweat gland distribution non-invasively.MethodsIn this study, 35 skin specimens from 10 fresh human cadavers without osmidrosis and retrospective ultrasonographic images from 20 patients with osmidrosis were used. Skin specimens were embedded in paraffin, thinly sliced, and finally stained with hematoxylin and eosin. Histologically, the apocrine and eccrine glands were evaluated, and the top and bottom depths of follicles were measured from the skin surface. In 33 MHz ultrasonography images, the depths of sweat glands were measured, and the mean grey value was calculated using Image J.ResultsCompared to histological data, 33MHz-UHFUS could be used to identify sweat glands as a hyperechoic structure between the dermis and fat layer. Furthermore, it could evaluate sweat gland distribution but could not distinguish between types of sweat glands.ConclusionsThe distribution of sweat glands in the axilla can be non-invasively evaluated via 33MHz-UHFUS.

Body mapping of regional sweat distribution in young and older males

PurposeGiven the pressing impact of global warming and its detrimental effect on the health of older populations, understanding age-related changes in thermoregulatory function is essential. Age differences in regional sweat distribution have been observed previously, but given the typically small measurement areas assessed, the development of whole body sweat maps for older individuals is required. Therefore, this study investigated age-related differences in regional sweat distribution in a hot environment (32 °C/50%RH) in young and older adults, using a body mapping approach.MethodsTechnical absorbent pads were applied to the skin of 14 young (age 24 ± 2 years) and 14 older (68 ± 5 years) males to measure regional sweat rate (RSR) at rest (30 min) and during exercise (30 min), at a fixed heat production (200 W m−2). Gastrointestinal (Tgi) and skin temperature (Tsk), heart rate, thermal sensation, and thermal comfort were also measured.ResultsWhole body sweat maps showed that despite equal heat production, healthy older males had significantly lower gross sweat loss (GSL) than the young and significantly lower RSR at almost all body regions at rest and at the hands, legs, ankles, and feet during exercise. The lower sweat loss in the older group coincided with a greater increase in Tgi and a consistently higher Tsk at the legs, despite subjectively feeling slightly cooler than younger individuals.ConclusionThese findings support the evidence of age-related deterioration in both autonomic and subjective responses in the heat and highlight the lower extremities as the most affected body region.

Sweat distribution and perceived wetness across the human foot: the effect of shoes and exercise intensity

This study investigates foot sweat distribution with and without shoes and the relationship between foot sweat distribution and perceived wetness to enhance guidance for footwear design. Fourteen females performed low-intensity running with nude feet and low- and high-intensity running with shoes (55%VO2max and 75%VO2max, respectively) on separate occasions. Right foot sweat rates were measured at 14 regions using absorbent material applied during the last 5 min of each work intensity. Perceptual responses were recorded for the body, foot and four foot regions. Foot sweat production was 22% greater nude (p < .001) and with shoes did not increase with exercise intensity (p = .14). Highest sweat rates were observed at the medial ankle and dorsal regions; lowest sweat rates at the toes. Perceptions of wetness and foot discomfort did not correspond with regions of high sweat production or low skin temperature but rather seemed dominated by tactile interactions caused by foot movement within the shoe. Practitioner summary: This study provides a detailed view of foot sweat distribution for female runners with and without shoes, providing important guidance for sock and footwear design. Importantly, perceptions of wetness and foot discomfort did not correspond with areas of high sweat production. Instead tactile interactions between the foot, sock/shoe play an important role. Abbreviations: VO2max: maximal oxygen consumption; HR: heart rate; RH: relative humidity; GSL: gross sweat loss; Nude-I1: without socks and shoes, low intensity running; Shod-I1: with socks and shoes, low intensity running; Shod-I2: with socks and shoes, high intensity running

Design of sports clothing for hot environments

The clothing design based on sweat distribution pattern is called as body mapping clothing. Comparisons of three designs of body mapped and one conventional design of T-shirt was done in a wearer testing at a controlled chamber of 33 °C and 60% relativity humidity in a treadmill at 12 km/h for 40 min followed by 10 min resting. It is concluded that with the full body mapped T-shirt the increase in skin temperature is reduced in the chest area, shoulder, the body back by 47%,44% and 55% respectively; the increase in skin micro climate relative humidity is reduced in the chest area, shoulder, the body back by 54%,39.2% and 53% respectively; the increase in heart beat rate is reduced by 5.1%; the subjective perceptions of skin temperature, skin moisture and comfort are better; the wearer will be able to improve the running performance due better comfort level in terms lesser increase skin temperature, skin micro climate relative humidity and heart beat rate.

Histological characteristics of hair follicle pattern in Indian bison (Bos gaurus), black buck (Antelope cervicapra) and nilgai (Boselaphus tragocamelus)

Background and Aim: Indian bison, Black buck and Nilgai are in danger of extinction because people are hunting them for their meat and horns for sports, trophies etc. These animals are also protected under International Union for Conservation of Nature and Natural Resources (IUCN) and Conservation on International trade in Endangered Species of Wild Fauna and Flora (CITES). Taking note of the vulnerability of these animals to extinction, we characterized the hair follicle pattern of these animals for future reference. This study included a total of 30 skin samples comprised of 8 samples of bison, 10 samples of black buck and 12 samples of nilgai. Materials and Methods: Skin samples were obtained from Sri Jayachamarajendra Zoological Park, Mysore, Karnataka, India and Bannerghatta Biological Park, Bangalore, Karnataka, India and also from confiscated skins from forest and police officials of Karnataka. The skin samples were processed and horizontal section of 6-7 µm thickness was used for the routine histological technique using different special staining techniques. Observation such as hair follicle pattern, sebaceous glands and sweat glands distribution, blood vessels, nerve fibre, collagen and elastic fibres were noted. Results: In the bison, compound hair follicles were uniformly distributed and were rectangular in shape comprising of a primary hair follicle associated with 3-4 secondary hair follicles in addition to their sebaceous glands. Uniformly distributed coiled tubular sweat glands were also noticed which were lined by simple cuboidal epithelium. In the black buck, the compound hair follicles were densely distributed and were arranged linearly in the dermis of skin. Within the compound follicle, linear arrangements of primary and secondary follicles were observed. Each primary hair follicle was supported by 24 secondary hair follicles and the primary hair follicle was always present at the centre when it was present with 2 secondary hair follicles. In nilgai, the compound hair follicles were densely distributed in the dermis of skin. The primary hair follicles were bilaterally surrounded by 2-3 secondary hair follicles. Each primary and secondary hair follicle was associated with sebaceous glands. Conclusion: The histological pattern of the hair follicle data was established and the hair follicle pattern will be of use in the identification of the wild ruminant skins which are commonly poached by the poachers. It will also be useful to compare the histological characteristics amongst the wild ruminants.

상반신의 부분별 발한량, 피부온과 주관적 감각 고찰

This study aimed to measure the amount of sweating on 12 parts of the upper body using absorption fabric and analyze subjective sensations. The study was conducted with 9 male subjects in climate chamber controled at <TEX>$30{\pm}0.5^{\circ}C$</TEX>, and <TEX>$55{\pm}5%$</TEX> RH. The result was that sweating amount of the upper back part was significantly more than upper front part. We assumed that forced convection flow cased by exercise decreased the sweating rate in the front. The skin temperature of upper front body rapidly decreased as soon as exercise starts and gradually increased with cessation of exercise. On the other hand, the skin temperature of palm increased with exercise and showed continuous increasing even exercise stopping all the experimental period. This is caused by thermoregulatory responses through vasodilatation on the peripheral area. Subjective sensations, such as thermal sensation, wet sensation, and thermal comfort showed the highest score at the time of exercise stop. This means the subjects felt more hot, wet, and uncomfortable after exercise stopped. Bur after wiping of sweat, subjective sensation scores were recovered rapidly. The present study has provided more detailed information on the upper body sweat distribution than previously available, which can be used in clothing design, thermo-physiological modeling, and thermal manikin design. We also think that results of the present study will play an important role in making the sweat distribution map.

Is Clipping Superior to Cauterization in the Treatment of Palmar Hyperhidrosis?

Endoscopic thoracic sympathectomy has been accepted as the most effective treatment for palmar hyperhidrosis (PH). However, there is a debate regarding the surgical techniques in terms of effectiveness, recurrence, and reversibility. In this study, sympathetic chain disruptions were compared in terms of whether the clipping or ablation technique had an effect on the long-term outcomes of patients who underwent thoracic sympathectomy for primary PH. All patients who underwent video-thoracoscopic sympathectomy for PH between May 2008 and October 2011 were included. Single-port bilateral sympathectomy was performed depending on the sweat distribution. As a standard approach, rib-based terminology was used to describe the blockade level of the sympathetic ganglia, and single-level R3 sympathectomy (between R3 and R4) was performed in all patients. The type of sympathectomy was changed. Monopolar electrocautery was first performed and 5-mm clips were then used for nerve disruption. Both techniques were evaluated and compared in terms of effectiveness, reversibility, and recurrence. Cauterization of the sympathetic chain was applied in 28 (47%) (Group A) patients and clipping in 32 (53%) patients (Group B). CH was the most common adverse effect and was observed in 43 (71.6%) patients (Group A, 71.4%; Group B, 71.8%; p = 0.8). The success rate was 93% for Group A and 100% for Group B (p = 0.15). The satisfaction rate for Group A was 83% and for Group B was 86% (p = 0.77). In Group A two patients (7%), and in Group B three patients (9%) requested reversibility because of severe compensatory hyperhidrosis. Overly dry hands were the other most common side effect and were identified in 12 (25%) patients. Recurrences were observed in 11 patients in Group A and 4 patients in Group B (19 vs. 6%; p = 0.01). The mean follow-up time was 33 ± 10.5 months (range, 13-53 months). Both clipping and cauterization are highly effective for the treatment of PH. The methods are comparable in terms of effectiveness and side effects despite the fact that the recurrence rate was higher in the cauterization group. Potential reversibility of compensatory sweating was not observed in our series. Identification of ideal candidates for surgery and education of patients about the permanent side effects of sympathectomy might make these techniques more convenient.

Viscose as an alternative to aramid in workwear: Influence on endurance performance, cooling, and comfort

Workwears are required to maintain optimum performance during dangerous, exhausting activities (e.g. those involving the fire brigade or police). The purpose of the present study was to compare two workwears (A and B) composed of underwear and outerwear with different fiber blends (A: 100% aramid; B: combination of fire resistant (FR) viscose/merino wool underwear and FR viscose/aramid outerwear) during strenuous physical activity. In a climatic chamber (25℃, 50% RH) participants had to walk on a treadmill until exhaustion occurred. Weight measurements were made for calculating evaporation, sweat residue, and sweat distribution. Endurance performance was assessed by time to exhaustion. Core temperature, heart rate, lactate, thermal comfort, microclimate between skin and underwear, surface temperature of the outerwear, and perceived exertion were also measured. The tested workwears caused no significant differences in time to exhaustion, core temperature, and thermal comfort. Sweat distribution differed significantly in the workwears. The underwear of workwear B caused less moisture accumulation in the outerwear and this may be a beneficial safety feature for the prevention of hazardous burns of the skin. Moisture accumulation in the outerwear may reduce thermal insulation and increase the possibility of evaporation whereby hot steam may move to the skin. The potential protective feature of the FR viscose/merino wool blended underwear and the economical price of viscose support the use of fire resistant (FR) viscose blended fabrics in workwears.

Design data for footwear: sweating distribution on the human foot

PurposeThe purpose of this paper is to provide footwear designers, manikin builders and thermo‐physiological modellers with sweat distribution information for the human foot.Design/methodology/approachIndependent research from two laboratories, using different techniques, is brought together to describe sweat production of the foot. In total, 32 individuals were studied. One laboratory used running at two intensities in males and females, and measured sweat with absorbents placed inside the shoe. The other used ventilated sweat capsules on a passive, nude foot, with sweating evaluated during passive heating and incremental exercise to fatigue.FindingsResults from both laboratories are in agreement. Males secreted more than twice the volume of sweat produced by the females (p&lt;0.01) at the same relative work rate. Both genders demonstrated a non‐uniform sweat distribution, though this was less variable in females. Highest local sweat rates were observed from the medial ankles (p&lt;0.01). The dorsal foot sweated substantially more than the plantar (sole) areas (p&lt;0.01). Sweating on the plantar side of the foot was uniform. Wearing shoes limited the increase in sweat production with increasing load, while the sweat rate of uncovered feet kept increasing with work and thermal load.Practical implicationsThe observed variation in sweat rate across the foot shows that footwear design should follow the body mapping principle. Fabrics and materials with different properties can be used to improve comfort if applied to different foot surfaces. The data also demonstrate that foot models, whether physical (manikins) or mathematical, need to incorporate the observed variation across the foot to provide realistic simulation/testing of footwear.Originality/value

Improved Procedure for Estimating Time-dependent Changes in Local Sweat Rates by Measuring Local Sweat Volumes

Sweat distribution over 21 body sites in 8 young males was described by determining the local sweat volume (LSRap), measured using absorbent pads throughout 3 different bicycle exercises performed at 35, 50, and 60% VO2max for 40 min, at 30°C and 50% relative humidity. The local upper back sweat rate was concurrently measured by the ventilated capsule method (LSRvc) in parallel with the absorbent method. The LSRap at the upper back correlated strongly with mean LSRvc at the position immediately above the absorbent pad (p<0.05). There were significant differences in LSRap among the 21 body sites within each exercise intensity (p<0.05). Regional comparisons showed a greater LSRap at the chest and back and lower LSRap at the flank, thighs, and legs. Moreover, LSRap was distributed symmetrically and was greater in the middle compared to the adjoining lateral sites. LSRvc data reanalysis of our previous studies on prepubertal boys, men, and women across a range of ages revealed that during passive and/or active heating, the LSRvc were arranged in order of lower limbs.

The Skin Interface - Meeting Point of Physiology and Clothing Science

This paper describes the relevance of knowledge of processes that happen at the skin for sports clothing design. It looks at skin temperature distribution while cooling, relevant e.g. to outdoor winter sports and mountaineering, at sweat distribution over the body while running, relevant e.g. to clothing designed for running in general and more particularly for exercise in warm and hot climates, and finally it looks into regional skin sensitivity, relevant for all fields of sports clothing design. As these areas interact heavily, the sports clothing designer needs to be aware of their influences and their interactions in order to optimise the clothing for the specific type of sport at hand.

Male and female upper body sweat distribution during running measured with technical absorbents

Body sweat distribution over the upper body in nine clothed male and female runners of equal fitness while running at 65% VO(2max) and subsequent 15-min rest in a moderate climate (25 degrees C, 53% rh) was investigated using technical absorbent materials to collect the sweat produced. No significant difference in whole body mass loss (male 474 SD 80; female 420 SD 114 g m(-2) h(-1)) nor surface weighted average of all tested zones for exercise (male 636 SD 165; female 565 SD 222 g m(-2) h(-1)) nor rest (male 159 SD 46; female 212 SD 75 g m(-2) h(-1)) were observed. Local sweat rate (LSR) ranges were large and overlapped substantially in most areas. Males showed higher LSR for the mid-front (P < 0.05), sides (P < 0.05), and mid lateral back (P < 0.01) compare to females. Both sexes showed similar sweat distribution patterns over the upper body with some exceptions. Males showed higher relative (local to overall) sweat rates than females for the mid lateral back (P < 0.001), while it was lower for the upper arm (P < 0.001), lateral lower back (P < 0.05), and upper central back (P < 0.05). Sweating in both sexes was highest along the spine, and higher on the back as a whole than the chest as a whole. Upper arm sweat rate was lowest. Males showed a higher ratio of highest to lowest LSR (4.4 vs. 2.8; P < 0.05). The present study has provided more detailed information, based on more subjects, on upper body sweat distribution than previously available, which can be used in clothing design, thermo-physiological modelling, and thermal manikin design.

Sweat distribution before and after repeated heat exposure.

We investigated the impact of short-term, moderate humidity heat acclimation upon sweat distribution. Eight males completed six daily heat exposures [cycling: ambient temperature 39.5 (0.2) degrees C, relative humidity 59.2 (0.8)%], during which auditory canal temperature (T(ac)) was maintained 1.4 degrees C above pre-exposure levels for 70 min by manipulating the work rate. On days 1 and 6, T(ac) and local sweat rates (m(sw): eight sites) were monitored. The pre-exposure, resting T(ac) and the T(ac) sweat threshold decreased from day 1 to day 6 [36.83 (0.05) degrees C vs 36.62 (0.05) degrees C, and 36.90 (0.05) degrees C vs 36.75 (0.05) degrees C, respectively; both P < 0.05]. However, the sweat-onset time, sweat sensitivity (delta m(sw)/deltaT(ac)) and established m(sw) were unaltered (P > 0.05). There was also no evidence of a post-acclimation redistribution in established m(sw) between the eight skin regions, though both the sweat sensitivity and established m(sw) for the forehead and hand were significantly greater than at the remaining sites (P < 0.05). It is concluded that the 5-day heat acclimation regimen provided only a minimal stimulus for sudomotor adaptation.

Effects of moisture absorption in clothing on the human heat balance

A theory of moisture absorption in clothing, with the associated effects of heat transfer, was developed and applied in a computer model. The model considers the body, underclothing, an outer layer, and the adjacent air layer. The theory was checked with an experiment involving four subjects. They wore heavy woollen clothing, which was either initially dry or humid, in both a warm and a cool environment. Model calculations and experimental results agree approximately upon the timing and magnitude of the effect of absorbing clothing on heat flows, temperatures and physiological reactions. Contrary to expectations the observed vapour resistance is lower in the heat than in the cold, probably due to differences in sweat distribution. It is pointed out that the usual way to determine the clothing characteristics by means of partitional calorimetry leads to considerable errors when the steady state has not been reached. In clothing that has high absorption properties the transient effects may be sustained for hours. Tests using the model show few beneficial effects of absorbing clothing on thermal sensation.

Eccrine sweat glands. Adaptations to physical training and heat acclimation.

Heat dissipation, under conditions of thermal stress, is mediated primarily by evaporation of sweat. Physical training has been shown to enhance sweat production by eliciting changes in the sensitivity of eccrine glands, total sweat output and distribution of gland activity. These adaptations afford partial acclimation. Heat acclimation produces similar changes, and also results in reduced sweat thresholds. To account for these different responses it has been hypothesised that physical training induces peripheral adaptations, while acclimation produces both peripheral and central modifications. It is suggested that repeated cutaneous heat detection may be essential to the development of central sudomotor changes.

Importance of skin temperature in the regulation of sweating.

Human sweating regulation at rest, evaluating thermal inputs effects on thermoregulatory center and internal hypothalamic and skin temperatures