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PubMed1993

Using human sweat to extract chromium from chromite ore processing residue: applications to setting health-based cleanup levels.

Chromite ore processing residue (COPR) containing measurable levels of hexavalent and trivalent chromium. [Cr(VI) and Cr(III), respectively] has been used to fill in low-lying areas in Hudson County, N.J. While it has been demonstrated that direct dermal contact with solutions containing Cr(VI) may elicit allergic contact dermatitis (ACD) in previously sensitized individuals, it is unknown to what degree skin moisture may solubilize Cr(VI) from COPR adhering to skin. An accurate estimate of this extraction potential is necessary to establish COPR concentrations of Cr(VI) and Cr(III) that are protective of eliciting ACD in sensitized individuals. The purpose of this study was to measure the extractable fraction of Cr(VI) and total chromium [Cr(III) and Cr(VI)] in soils impacted by COPR using human sweat as the extractant. Human sweat was collected from seven male volunteers. Samples of COPR material containing the following Cr(VI) and total chromium concentrations were collected: Cr(VI), 16, 136, and 1240 ppm; total chromium, 932 and 6660 ppm. The samples were sieved to obtain a uniform particle size < 500 microns. The samples were then mixed with human sweat at 30 degrees C for 12 h, after which the sweat was filtered and analyzed to determine the dissolved concentration of Cr(VI) and total chromium. The data from these analyses show that no detectable levels (limit of detection = 0.010 ppm) of Cr(VI) were leached from COPR containing 16 ppm Cr(VI). At Cr(VI) concentrations of 136 and 1240 ppm, less than 0.1% of the Cr(VI) present in the COPR sample was extracted into sweat, and sweat concentrations were 0.133 ppm Cr(VI) or less. Similarly, the amount of Crtotal extracted was 0.3% or less at COPR concentrations as high as 6600 ppm Crtotal, and sweat concentrations were 2.3 ppm Crtotal or less. If a minimum concentration of 10 ppm (Bagdon and Hazen, 1991) to 54 ppm (Paustenbach et al., 1992) Cr(VI) in sweat is required to elicit an ACD response in chromium-sensitive individuals, the current study results suggest that a COPR Cr(VI) concentration of at least 10,000-54,000 ppm would be required to elicit ACD. If 500 ppm (or greater) of solubilized Cr(III) is required to elicit an ACD response (NJDEPE, 1992a), then a COPR concentration of 250,000 ppm Cr(III) or greater would be required to elicit an allergic response. These results suggest that ACD is unlikely to occur as a result of environmental exposure to the COPR.

Adult↗

PubMed1986

Iron losses in sweat.

The losses of iron in whole body cell-free sweat were determined in eleven healthy men. A new experimental design was used with a very careful cleaning procedure of the skin and repeated consecutive sampling periods of sweat in a sauna. The purpose was to achieve a steady state of sweat iron losses with minimal influence from iron originating from desquamated cells and iron contaminating the skin. A steady state was reached in the third sauna period (second sweat sampling period). Iron loss was directly related to the volume of sweat lost and amounted to 22.5 micrograms iron/l sweat. The findings indicate that iron is a physiological constituent of sweat and derived not only from contamination. Present results imply that variations in the amount of sweat lost will have only a marginal effect on the variation in total body iron losses.

Adult↗

PubMed2003

Sweat test results in children with primary protein energy malnutrition.

OBJECTIVES: In underdeveloped and developing countries where protein energy malnutrition (PEM) is common, it is sometimes difficult to exclude the diagnosis of cystic fibrosis (CF) in malnourished children because both primary PEM and CF share similar symptoms, signs, and laboratory findings, such as elevated sweat chloride value. This study was performed to investigate sweat test results and determine percentile values in children with primary PEM. METHODS: A total of 90 children with PEM and 30 healthy children were included. PEM was classified according to criteria defined by Gomez, Waterlow, and McLaren. Sweat tests were performed using the Macroduct conductivity system. RESULTS: Patient age and gender did not affect the test results (P > 0.05). The mean sweat conductivity (equivalent NaCl mMol/L) of patients with PEM was higher than that of controls (P < 0.001) and increased with the degree of malnutrition (P < 0.001). Inverse correlations between sweat conductivity and weight for age, height for age, and weight for height were detected (P < 0.001). The highest value was found in children with wasting and stunting, followed by those with stunting (P < 0.05) and those with marasmic kwashiorkor (P < 0.01). Of all children with PEM, 6.7% had elevated sweat test results that normalized after nutritional management; of children with third degree PEM, the figure was 20%. Ninety-fifth percentile values of first, second, and third degree malnutrition were 47 mMol/L, 49 mMol/L, and 69 mMol/L, respectively. CONCLUSION: Elevated sweat test result is not an important problem, especially in first and second degree PEM, but borderline values can be detected in as many as 20% of cases of third degree malnutrition. Sweat conductivity may increase to 69 mMol/L in children with stunting, those with wasting and stunting, and in those with third degree PEM.

Case-Control Studies↗

PubMed1996

The effects of heat and exercise on sweat iron loss.

Arm sweat was collected from nine male and nine female athletes sitting in a hot environment (HR, 40 degrees C) and exercising at 50% VO2max in neutral (NE, 25 degrees C) and hot (HE, 35 degrees C) environments to compare sweat iron concentrations and losses. Whole body sweat rate was determined from weight loss at 30-min intervals for 1 h. Sweat iron concentration was significantly higher during HR and NE than during HE, but was not significantly different between males and females. During exercise, sweat iron concentration decreased significantly from 30 to 60 min. Whole body sweat rates differed significantly across all environments with the highest rate in HE and the lowest in HR. Males lost significantly more sweat during exercise than females, but the difference at rest was not significant. Estimated whole body iron loss was significantly greater during exercise (NE = 0.08 mg.m-2.h-1, HE = 0.077 mg.m-2.h-1) than rest (0.039 mg.m-2.h-1), and the average iron loss was significantly greater in males (0.09 mg.m-2.h-1) than females (0.04 mg.m-2.h-1). Results suggest that the use of resting sweat iron concentration to estimate iron loss for 1 h of exercise in neutral environments is accurate but may overestimate iron loss during exercise in hot environments and during more prolonged exercise.

Adult↗

PubMed1992

Sweating response to moderate thermal stress in atopic dermatitis.

The local sweating response to thermal stress (mean ambient temperature 33 degrees C) was assessed under resting conditions on the non-eczematous back skin of 26 young men with atopic dermatitis (AD) and in 22 non-atopic controls with other dermatoses. The baseline (transepidermal) water loss was separately determined at room temperature (mean 23.6 degrees C) to calculate the pure sweat loss. A gravimetric collecting method was used for the measurements at 40, 60 and 80 min. In the heated room the sweat loss in AD patients was significantly lower at all time intervals. The cumulative sweat loss was 50-60% lower in AD patients than in the controls (P less than 0.02). Subjects with dry AD skin had a lower sweat loss than subjects with normal-looking skin. Compared with controls the sweat loss in AD patients was lowest at 40 min, suggesting a retarded sweating response. Half of the patients with AD and half of the controls had active participation in sports, and showed a greater sweat loss compared to the non-sporting subjects in the same group.

Adult↗

PubMed1989

Transepidermal water loss with and without sweat gland inactivation.

The influence of eccrine sweating on transepidermal water loss (TEWL) was investigated. TEWL was simultaneously measured on both forearms, with and without topical inactivation of the eccrine sweat glands by 0.3 ml of 0.5% aqueous scopolamine hydrobromide (HBr), applied under 1 h occlusive patches. The degree of sweat inhibition, after exercise, was measured at 2, 3 and 4 h after patch removal. In 42 out of 44 subjects, complete sweat inhibition (on exercise) was achieved only at 4 h after removal. After a 15-min rest in a room at 20 degrees C, the pre-exercise TEWL values (at 4 h) on the treated and untreated sites were not different (P greater than 0.05), in 38 out of 44 subjects. By this rest period, sweating due to slight physical, thermal or even emotional stimuli may be prevented in most subjects. In the other 6 subjects, the pre-exercise TEWL values (at 4 h) on the untreated site were 1-1.8 g/m2h higher than (P less than 0.001) on the treated site, due to emotional sweating. Thus, accurate baseline TEWL measurements may only be made after anticholinergic suppression of the sweat glands. In this way, accurate TEWL measurements may be made even outside favourable laboratory conditions, at industrial sites etc., where circumstances are far from ideal. The effect of this agent applied to a skin site previously irritated artificially by a 24-h occlusive sodium lauryl sulphate (SLS, 0.3 ml, 0.5% aq.) patch, was also investigated in 17 subjects. In all subjects, 4 h after removal, sweating (on exercise) was completely inhibited on the scopolamine-treated site, pre-irritated with SLS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1999

Effects of treadmill exercise on sweating in three breeds of goats.

OBJECTIVE: To compare the sweating responses of three breeds of goats to exercise at 30 degrees C. DESIGN: Factorial experiment with two goats of each of three breeds exercised for 60 min at 3 km/h and 30 degrees C on 6 days. PROCEDURE: Two mature females of the Anglo-Nubian, Saanen and Toggenburg breeds were used. Rectal temperature, respiration rate and sweating rate at three sites were recorded every 20 min during six replicates of exercise at 48 h intervals on a treadmill. RESULTS: Respiration rate varied with time and breed (P < 0.01) and increased from 20 +/- 2 breaths/min to 135, 195 and 260/min after 60 min exercise in Anglo-Nubian, Saanen and Tottenburg goats, respectively. Bread differences in rectal temperature were small but significant (P < 0.001), and mean values increased from 38.9 degrees C before exercise to 39.7 degrees C after 1 h exercise. The breed x sites interaction for sweating was significant (P < 0.01). On the rump breed differences in sweating rate were not significant. On the loin, Toggenburg goats started to sweat most rapidly and reached maximal values of 80.2 +/- 10.6 g/m2/h after 20 min and then decreased to 70.0 +/- 4.3 g/m2/h at 60 min. Sweating rate on the ear was highest in Toggenburg goats, followed by those of Saanen and Anglo-Nubian goats (P < 0.05), but the differences were small (7 g/m2/h); peak values of 67.3 to 76.1 g/m2/h were recorded after 20 min. CONCLUSION: Respiration and sweating rates increased significantly during exercise in all three breeds of goats, but breed differences were marked only for respiration rate. The goats sweated more on the rump than on the loin on ear, with peak values after 40 min of exercise.

Analysis of Variance↗

PubMed1995

Equine sweat composition: effects of adrenaline infusion, exercise and training.

Significant alterations in plasma electrolyte concentrations have been reported in horses following prolonged exercise, resulting from loss of hypertonic sweat. Sweat was collected from 10 horses undergoing a 10 week training programme; 5 at moderate intensity, to speeds of 10 m/s and 5 at low intensity, to speeds of 5 m/s. Sweat was collected from 2 sites in response to a submaximal exercise test (30 min at 50% VO2max and during an adrenaline infusion (dose mean +/- s.d.; 0.3 +/- 0.05 g/kg over 30 min). Sweat samples were analysed for sodium, chloride, potassium, protein, magnesium, calcium and urea concentrations. Sweat produced in response to exercise and adrenaline infusion was hypertonic and showed no significant differences in composition following training. However, the [NaCl] of sweat rose with increased duration of sweating. Sweat produced in response to adrenaline infusion was more dilute than that produced in response to exercise, which may be related to sympathetic outflow during exercise.

Animals↗

PubMed2006

Peripheral amplification of sweating--a role for calcitonin gene-related peptide.

Neuropeptides are the mediators of neurogenic inflammation. Some pain disorders, e.g. complex regional pain syndromes, are characterized by increased neurogenic inflammation and by exaggerated sudomotor function. The aim of this study was to explore whether neuropeptides have a peripheral effect on human sweating. We investigated the effects of different concentrations of calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and substance P (SP) on acetylcholine-induced axon reflex sweating in healthy subjects (total n = 18). All substances were applied via dermal microdialysis. The experiments were done in a parallel setting: ACh alone and ACh combined with CGRP, VIP or SP in various concentrations were applied. Acetylcholine (10(-2) m) always elicited a sweating response, neuropeptides alone did not. However, CGRP significantly enhanced ACh-induced sweating (P < 0.01). Post hoc tests revealed that CGRP in physiological concentrations of 10(-7)-10(-9) m was most effective. VIP at any concentration had no significant effect on axon reflex sweating. The duration of the sweating response (P < 0.01), but not the amount of sweat, was reduced by SP. ACh-induced skin blood flow was significantly increased by CGRP (P < 0.01), but unaltered by VIP and SP. The results indicate that CGRP amplifies axon reflex sweating in human skin.

Acetylcholine↗

PubMed1993

Zinc loss in sweat of athletes exercising in hot and neutral temperatures.

Zinc (Zn) loss from sweat of 9 male and 9 female athletes exercising under hot (35 degrees C, HE) and neutral (25 degrees C, NE) conditions was examined. Subjects exercised at 50% VO2max on a cycle ergometer for 1 hr during each trial. Cell-free sweat samples were analyzed for Zn by atomic absorption spectrophotometry. There was a significant interaction of time, gender, and temperature for whole-body sweat rates (WBSR). WBSR for males were higher during both trials and at each time. WBSR from the second half of exercise were higher than those from the first half for both sexes and temperature conditions. Sweat Zn concentration was higher in the NE than in the HE, but when the sweat rates were included, the rate of Zn loss was no different between HE and NE. Zn concentration of the sweat for the first half of exercise was over twice that of the second half. Sweat Zn concentration of the men was no different than that of the women; however, due to greater sweat rate, men had significantly higher Zn losses. Although total Zn losses are estimated to be relatively low compared to the RDA, exercise at moderate intensities may increase surface Zn losses.

Adult↗

PubMed1982

Sweating sensitivity and capacity of women in relation to age.

Ten postmenopausal and ten younger women rested for 2 h in a 40 degrees C, 22.2-Torr vapor pressure environment. Sweating response was monitored by resistance hygrometry for onset, a platform balance for whole-body sweat rate, and five individual capsules for regional sweat rate. Other variables measured included forearm blood flow, heart rate (HR), mean skin (Tsk) and rectal (Tre) temperatures, sweat electrolytes (Na+ and K+), oxygen uptake, and plasma volume changes. Preliminary tests included maximal aerobic power (VO2max) and percent body fat. Heat stress did not elicit any significant differences in sweating response between age groups. Indices of heat strain, Tre and HR, were also similar for both groups. The only significant difference between younger and older women was a higher Na+ concentration in the forearm sweat of postmenopausal women. No thermoregulatory responses were related to age, but both sweat rate (r = 0.48) and peak Tsk (r = -0.43) were related to VO2max. For healthy, active, older women aging did not diminish the functional capacity of the sweating mechanism to cope with heat stress while resting in this specific thermal environment.

Adult↗

PubMed1991

Regional differences in the sweating responses of older and younger men.

Ten older (60-71 yr) and nine younger (20-25 yr) active healthy men were exposed to passive heating [by placing the lower legs and feet in a 43 degrees C water bath for 60 min while sitting in a warm (35 degrees C, 45% relative humidity) chamber] in summer and winter. The increase in rectal temperature (Tre) was significantly (P less than 0.05) greater, and mean skin temperature and forearm blood flow were lower, for the older men in both seasons. Total sweating rate was lower in the older men, but significantly (P less than 0.05) so only in the summer. The Tre threshold for sweating was unaffected by either age or site (back vs. thigh). The local sweating rate (msw) on the thigh was significantly lower (P less than 0.05) for the older men throughout the exposure, whereas there were no significant age-related differences for the average or peak values of back msw, although lesser sweating on the back occurred during the first 30 min of exposure. The decreased msw on the thigh was due to a lower sweat output per heat-activated sweat gland rather than from recruitment of fewer glands. It was concluded that regional differences exist in the age-related decrement in sweat gland function. Furthermore, these findings suggest that aging leads to a decreased ability to maintain body temperature with passive heating of the extremities, which may be attributed in part to decreased regional sweat gland function.

Adult↗

PubMed1992

Variation of sweat sodium and chloride with age in cystic fibrosis and normal populations: further investigations in equivocal cases.

Patients attending cystic fibrosis clinics had sweat sodium and chloride concentrations measured, were reassessed clinically and had DNA studies performed. Sweat test results were compared with a matched control population. In both populations sweat sodium increased with age up to 12 years, and did not change significantly thereafter. The age-related increase was significantly less in the cystic fibrosis group. Sweat chloride increased with age in normal, but not in cystic fibrosis children. After age 12 years there was no age-related change in the normal group, and a fall with age in the cystic fibrosis group. Sweat chloride provided the best discrimination between normal and cystic fibrosis populations and this was particularly important in older subjects. Combining sweat sodium and chloride results did not improve discrimination. Nine patients were identified with equivocal sweat chloride results. DNA studies showed six of these subjects were heterozygous for the delta F508 mutation in the cystic fibrosis gene. Clinical assessment did not always resolve cases with borderline sweat chloride results.

Adolescent↗

PubMed1978

The significance of the sweat test in chronic pancreatitis.

In order to study the disposition which is thought to be latent in chronic pancreatitis, we investigated the sweat chloride concentration of 95 normal subjects, 43 cases of chronic pancreatitis, 12 cases of cholelithiasis, 15 cases of peptic ulcers, 16 cases of hepatic diseases and 23 cases of diabetes mellitus with the sweat test, using the method of pilocarpine iontophoresis. We obtained the following results. (1) In normal subjects, the sweat chloride concentration was inclined to rise gradually with age from childhood to adulthood; the mean value of sweat chloride concentration was 30.0 mEq/liter in adults from 20 years old, and the upper limit was about 60 mEq/liter. (2) The mean value of sweat chloride concentration was 60.0 mEq/liter in chronic calcifying pancreatitis; this value was markedly higher than that of control subjects of the same age (p is less than 0.001). (3) The mean value of sweat chloride concentration in cholelithiasis, peptic ulcer and hepatic diseases did not differ significantly from control subjects. The mean value of sweat chloride concentration in diabetes mellitus was significantly higher than that of control subjects (p is less than 0.01), but was significantly lower than that in chronic pancreatitis (p is less than 0.01). (4) It was supposed that some cases of chronic pancreatitis have a congenital disposition toward abnormal secretion of sweat glands and epithelium in the pancreatic duct, resembling cystic fibrosis, and this disposition leads easily to pancreatic disorders when the individual is exposed to various external factors.

Adolescent↗

PubMed1988

Effect of facial cooling during heat acclimation process on adaptive changes in sweating activity.

On assumptions that tympanic temperature (Tty) reflects brain temperature and that the latter can be lowered by cooling of the face, effect of facial cooling during acclimation process on adaptive changes in sweating activity was examined, in comparison with the results of our previous studies on heat acclimation with controlled hyperthermia. Face fanning, by which Tty was clamped at approximately 37.1 degrees C, was combined with either of the following 9-day acclimation procedures: 90-min heating in a "Sauna box," keeping mean skin temperature slightly above 40 C, or 90-min exercise on a bicycle, clamping rectal temperature (Tre) at approximately 38 degrees C. Each procedure was imposed on the same four male subjects on different occasions, two of whom had participated in our previous experiments. Sweat tests, carried out before and immediately after the completion of the procedure, consisted of measurements of local sweat rates, whole body sweat rate, Tre, Tty, and skin temperatures on 5 areas, and of calculations of mean body temperature (Tb) and the rate of sweat expulsions (Fsw, as an indicator of central sudomotor activity). No or only a slight increase in sweating activity was observed following the acclimation procedures with face fanning, whereas similar procedures without face fanning had resulted in substantial enhancement of sweating activity in most of the cases, which had been attributed mainly to adaptive changes in central sudomotor activity (as indicated by a shift of the regression line relating Fsw to Tb). Similar results were obtained in an additional series of experiments, where the effects of 9-day 90-min exercise in heat, clamping Tre at approximately 38.2 degrees C, with and without facial cooling, were compared with each other in a subject. From the above results it is inferred that Tty reflects brain temperature and that enhancement of sweating activity induced by repeated heat load is strongly impeded, if not accompanied, by an elevation of brain temperature.

Acclimatization↗

PubMed1990

The stability of iodine in human sweat.

The relation between the sweat iodine loss and the urinary iodine excretion was studied on 13 physically active male athletes. There were no statistical differences between the sweat iodine concentrations before and after high iodine food intake, no difference between those before and after 1-h strenuous exercise, or no difference between those of the goitrous and the non-goitrous. These results indicate that the sweat iodine concentration is quite steady and the total iodine loss per day seems to be directly related to the volume of the sweat lost in each subject. The concentration variation of sweat iodine among individuals is small. The mean concentration of 13 athletes during 8 consecutive days was about 37 +/- 6.6 micrograms/l. By comparing the iodine concentration of urine and sweat, the iodine concentration of sweat seems to be more stable than that of urine. The results indicated that the urinary iodine excretion plays a regulatory role for iodine balance in the body and that iodine appeared to be an essential constituent of sweat.

Adolescent↗

PubMed2002

Validity of self-reported exercise-induced sweating as a measure of physical activity among patients with coronary artery disease.

BACKGROUND: In several epidemiological studies, self-reported exercise-induced sweating has been used as a measure of physical activity (PA). Among healthy subjects it is moderately well associated with other measures of PA and physical fitness, but its validity among patients with coronary artery disease (CAD) has not yet been established. METHODS: In a self-administered questionnaire, 233 patients undergoing coronary angiography replied to the question 'In the past 4 weeks, how often have you exercised vigorously enough to work up a sweat?" Patients also gave the frequency and duration of different PA. We examined the association of the sweat frequency question with light (<4 metabolic equivalents [METs]), moderate (4.0-5.9 METs) and intense (>6 METs) PA, and tested the association with maximum exercise capacity. RESULTS: The frequency of self-reported exercise-induced sweating was significantly (p <0.001) associated with both moderate and intense PA. The correlation coefficient of moderate and intense PA with sweat frequency was r = 0.34 (p<0.001), and r = 0.44 (p <0.001) for the respective PA of >30 minutes' duration. The strength of the association between sweat frequency and caloric expenditure per time was similar (moderate and intense PA, r = 0.43, p <0.001). There was a significant correlation between maximum exercise capacity measured in METs and sweat frequency (r = 0.37, p <0.001). CONCLUSIONS: These results suggest that for studies among patients with CAD, assessment of the frequency of self-reported exercise-induced sweating provides useful information regarding moderate and intense PA as well as physical exercise capacity.

Aged↗

PubMedDate not supplied

Assessing quality assurance for sweat chloride testing.

Variations in sweat chloride tests were analyzed. A total of 1,806 sweat test results were analyzed for intra-assay and inter-assay variation in sweat chloride concentration and sweat weight. The mean and standard deviation of sweat chloride determinations for the negative population was 11.63 mmol/L (7.20 s.d.); for the borderline population was 50.01 mmol/L (6.27 s.d.); and for the positive population was 96.75 mmol/L (s.d. = 13.81). The percent of sweat tests that were negative was 86.77, borderline, 3.82, and positive, 9.41. The variation, represented as the standard deviation, between bilateral sweat chloride values on the same patient for negative results is 10.23 and for positive results is 14.60. The average variation within a patient with regard to sweat weight is 19%. Clinical laboratory scientists can use this information in assessing their own quality assurance procedures and patient results.

Chlorides↗