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At least 55 records · Page 3Linked to original sources

PubMed1992

An improved method for measurement of sweat expulsions during profuse sweating.

We present an improved ventilated-capsule method of recording for clear sweat expulsion patterns using nitrogen gas as a carrier gas heated to promote sweat evaporation. With this method, sweat expulsion patterns were more clearly recorded than with the conventional ventilated-capsule method. Taking the derivatives of these recordings of sweating expulsions could eliminate slow fluctuation components in the patterns of sweating. The results indicate that this method is useful in providing more-accurate measurements of sweat expulsion frequencies during profuse sweating.

Adult↗

PubMed1996

Sweat testing in opioid users with a sweat patch.

For many years, toxicologists have detected the presence of drugs of abuse in biological materials using blood or urine. In recent years, remarkable advances in sensitive analytical techniques have enabled the analysis of drugs in unconventional samples such as sweat. In a study conducted in a detoxification center, sweat patches were applied to 20 known heroin abusers. Subjects wore the patch with minimal discomfort for five days. During the same period, two urine specimens were also collected. Target drugs analyzed either by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS) included opiates (heroin, 6-monoacetylmorphine, morphine, codeine), cocaine (cocaine, benzoylecgonine, ecgonine methyl ester), delta 9-tetrahydrocannabinol, benzodiazepines (nordiazepam, oxazepam), amphetamines (amphetamine, methamphetamine, methylenedioxyamphetamine [MDA], methylenedioxymethamphetamine [MDMA], methylenedioxyethylamphetamine [MDEA]), and buprenorphine. Patches were positive for opiates in 12 cases. Heroin (37-175 ng/patch) and/or 6-acetylmorphine (60-2386 ng/patch) were identified in eight cases, and codeine exposure (67-4018 ng/patch) was determined in four cases. When detected, heroin was always present in lower concentrations than 6-acetylmorphine, which was the major analyte found in sweat. Cocaine (324 ng/patch) and metabolites were found in only one case. delta 9-Tetrahydrocannabinol (4-38 ng/patch) was identified in nine cases. Benzodiazepine concentrations were very low, ranging from 2 to 44 and from 2 to 15 ng/patch for nordiazepam and oxazepam, respectively. MDEA (121 ng/patch) and its metabolite, MDA (22 ng/patch), were detected in one case. Buprenorphine, which was administered as therapy under close medical supervision, was detected in the range 1.3-153.2 ng/patch with no apparent relationship between the daily dose and amount excreted in sweat. All the urine tests were consistent with the sweat findings, but to identify the same drugs it was necessary to test two urine specimens along with only one sweat specimen. It was concluded that sweat testing appears to offer the advantage of being a relatively noninvasive means of obtaining a cumulative estimate of drug exposure over the period of a week. This new technology may find useful applications in the treatment and monitoring of substance abusers, as the patch provides a long-term continuous monitor of drug exposure or noncompliance.

Amphetamines↗

PubMed1976

Effects of subcutaneously administered adrenaline on human eccrine sweating, with special reference to the physiological significance of the adrenergic sweating mechanism.

The effects of a small dose (3-6 mug/kg) of subcutaneously administered adrenaline on thermal sweating were studied while subjects were at rest and during or after excerise by means of continuous monitoring by resistance hygrometry of the sweat rate in the forearm area. In most cases, the sweat rate either decreased or did not change significantly following the adrenaline injection, however, among athletic subjects it showed a mild increase in a few cases, mostly during or after exercise. In the area receiving the intradermal injection of an alpha-adrenergic blocking agent, tolazoline, phentolamine or dihydroergotoxine, subcutaneous adrenaline consistently caused an increase in sweat rate. Adrenaline (15 mug) was injected intravenously with similar results. Noradrenaline was used in place of adrenaline in some cases, and the results were essentially the same as, but less distinct than, those with adrenaline. The results indicate that a small dose of subcutaneous adrenaline has dual effects, with the sweat-inhibitory effect generally predominating over the sweat-facilitatory one, with occasional exceptions in association with exercise and/or physical training. The former effect is largely secondary to its vasconstrictive effect, whereas the latter appears to be secondary to its systemic effects, such as central and calorigenic ones. It is concluded that adrenaline within a physiological range exerts no direct action on human eccrine sweat glands.

Adrenergic alpha-Antagonists↗

PubMedDate not supplied

Sweating patterns in humans: I. Exercise- and pilocarpine-induced forehead sweating in healthy individuals.

In cluster headache, forehead sweating is frequently pathological and for this reason it is important to know the normal pattern. In the present work, sweating was induced by exercise and pilocarpine in 14 healthy individuals in the age group 24-50 years. A comparison was also made with patterns of heat-induced forehead sweating. No definite left-right asymmetry or medial-lateral preponderance were observed. As expected, the sweat patterns following body heating and exercise were rather similar. However, there was a significant relative increase in lateral forehead sweating with heat-induction as compared to pilocarpine-induction. In comparative intra- or inter-individual studies of forehead sweating, the method of sweat provocation may, therefore, not be indifferent.

Adult↗

PubMed2005

Effects of short-term exercise in the heat on thermoregulation, blood parameters, sweat secretion and sweat composition of tropic-dwelling subjects.

This study investigates the effects of a short-term aerobic training program in a hot environment on thermoregulation, blood parameters, sweat secretion and composition in tropic-dwellers who have been exposed to passive heat. Sixteen healthy Malaysian-Malay male volunteers underwent heat acclimation (HA) by exercising on a bicycle ergometer at 60% of VO2max for 60 min each day in a hot environment (Ta: 31.1+/-0.1 degrees C, rh: 70.0+/-4.4%) for 14 days. All parameters mentioned above were recorded on Day 1 and at the end of HA (Day 16). On these two days, subjects rested for 10 min, then cycled at 60% of VO2max for 60 min and rested again for 20 min (recovery) in an improvised heat chamber. Rectal temperature (Tre), mean skin temperature (Tsk) heart rate (HR), ratings of perceived exertion (RPE), thermal sensation (TS), local sweat rate and percent dehydration were recorded during the test. Sweat concentration was analysed for sodium [Na+]sweat and potassium. Blood samples were analysed for biochemical changes, electrolytes and hematologic indices. Urine samples were collected before and after each test and analysed for electrolytes.After the period of acclimation the percent dehydration during exercise significantly increased from 1.77+/-0.09% (Day 1) to 2.14+/-0.07% (Day 16). Resting levels of hemoglobin, hematocrit and red blood cells decreased significantly while [Na+]sweat increased significantly. For Tre and Tsk there were no differences at rest. Tre, HR, RPE, TS, plasma lactate concentration, hemoglobin and hematocrit at the 40th min of exercise were significantly lower after the period of acclimation but mean corpuscular hemoglobin and serum osmolality were significantly higher while no difference was seen in [Na+]sweat and Tsk. It can be concluded that tropic-dwelling subjects, although exposed to prolonged passive heat exposure, were not fully heat acclimatized. To achieve further HA, they should gradually expose themselves to exercise-heat stress in a hot environment.

Acclimatization↗

PubMed1979

The ultrastructure of the sweat glands of the ox, sheep and goat during sweating and recovery.

The ultrastructure of the sweat glands of cattle, sheep and goats was studied before, during, and after, exposure of the animals to controlled warm environments. In cattle, sweating induced little ultrastructural change in the gland, although fluid-filled spaces appeared between the myo- and secretory epithelial layers. The mechanism appears to be one of fluid transport and exocytosis of secretory vesicles, which in this species seem to be derived from the Golgi apparatus and/or mitochondria. The glands of the sheep and goat also displayed signs of vesicle exocytosis and of fluid transport during sweating. The sweating 'fatigue' in these species was apparently due to failure of the secretory cells, some of which ruptured and were extruded into the lumen. The evidence during subsequent recovery indicates that neighbouring cells spread to make contact, encase remnants of atretic cells between them and the underlying myoepithelium, and engulf them. Sweat in these species appears to be formed (a) by secretion and (b) from cells which can no longer meet the demands of stimulation. The role in sweating of cell replacement, and of undifferentiated cells found between the myo- and secretory epithelia, is discussed.

Animals↗

PubMed1997

Use of dew-point hygrometry, direct sweat collection, and measurement of body water losses to determine sweating rates in exercising horses.

OBJECTIVE: To compare dew-point hygrometry, direct sweat collection, and measurement of body water loss as methods for determination of sweating rate (SR) in exercising horses. ANIMALS: 6 exercise-trained Thoroughbreds. PROCEDURE: SR was measured in 6 horses exercising at 40% of the speed that elicited maximum oxygen consumption for 45 km, with a 15-minute rest at the end of each 15-km phase. Each horse completed 2 exercise trials. Dew-point hygrometry, as a method of local SR determination, was validated in vitro by measurement of rate of evaporative water loss. During exercise, local SR was determined every 10 minutes by the following 2 methods: (1) dew-point hygrometry on the neck and lateral area of the thorax, and (2) on the basis of the volume of sweat collected from a sealed plastic pouch attached to the lateral area of the thorax. Mean whole body SR was calculated from total body water loss incurred during exercise. RESULTS: Evaporation rate measured by use of dew-point hygrometry was significantly correlated (r2 = 0.92) with the actual rate of evaporative water loss. There was a similar pattern of change in SR measured by dew-point hygrometry on the neck and lateral area of the thorax during exercise, with a significantly higher SR on the neck. The SR measured on the thorax by direct sweat collection and by dew-point hygrometry were of similar magnitude. Mean whole body SR calculated from total body water loss was not significantly different from mean whole body SR estimated from direct sweat collection or dew-point hygrometry measurements on the thorax. CONCLUSIONS: Dew-point hygrometry and direct sweat collection are useful methods for determination of local SR in horses during prolonged, steady-state exercise in moderate ambient conditions. Both methods of local SR determination provide an accurate estimated of whole body SR.

Animals↗

PubMed1983

Sweating and sweat decline of resting men in hot humid environments.

Time courses of the rates of sweating, drippage and evaporation were studied in hot humid environments. Resting subjects wearing only briefs were exposed to humid conditions, before, during and after humid heat acclimation, so that different levels of skin wettedness could be studied on the entire body. In addition, local sweat rate was measured on the right upper limb, which was enclosed in a highly ventilated arm-chamber. Thus, the arm remained drier than the rest of the body surface. The results confirm that sweating efficiency is related to the skin wettedness level, and that the decline in intensity of sweating is linked to maximal inefficient sweat drippage before the onset of hidromeiosis. Comparison of general and local sweat decreases confirms that hidromeiosis originates from skin hydration. However it is likely that some factor related to blood content acts on the hidromeiotic process, at least after humid heat acclimation.

Acclimatization↗

PubMed1991

Effects of ageing and physical training on the peripheral sweat production of the human eccrine sweat gland.

Epidemiological studies suggest that thermoregulatory function declines with ageing. Therefore, it was the purpose of this study to examine the effects of physical training and ageing on the peripheral sweat rate of the human sweat gland. Maximum oxygen uptake and peripheral sweat rate (pilocarpine iontophoresis) were determined in 40 male volunteers (10 sedentary younger men, 10 endurance-trained younger men, 10 sedentary older men, and 10 endurance-trained older men). Maximum oxygen uptake and peripheral sweat rate were significantly (p less than 0.05) greater in the two endurance-trained groups compared to their sedentary counterparts. Furthermore, when matched for maximum oxygen uptake, younger and older men had similar mean peripheral sweat rate values. These results suggest that participation in lifelong aerobic exercise may retard the decrease in peripheral sweat production usually associated with ageing. Further work is needed, however, to determine if such changes can improve overall thermoregulatory function in elderly people.

Adult↗

PubMed2005

Effects of body posture on local sweating and sudomotor outflow as estimated using sweat expulsion.

To estimate the effects of changes in body posture on sudomotor function, sweat rates on the forearm, chest and thigh, tympanic temperature (Tty), and skin temperatures were recorded in an upright sitting and a supine position under a hot environment of 40 degrees C Ta and 40% relative humidity for 60 min. Sweat expulsions were identified on sweat rate curves and their rates (Fsw) were calculated. Tty was higher, and its initial fall was greater, in the supine position than in the sitting position. On the forearm and the chest, the regression line relating sweat rate to mean body temperature (Tmb) had a gentler slope in the supine position, whereas on the thigh, it showed a steeper slope. The regression line relating Fsw to Tmb had a steeper slope in the supine position than in the sitting position, suggesting that the gain in the mechanisms for central integration and rhythm-generation was enhanced in the supine position. The parameter of sweat rate divided by Fsw was lower on the forearm and the chest, whereas it was higher on the thigh in the supine position than in the sitting position, suggesting that sudomotor outflow was modified at the spinal cord in association with skin pressure. It was concluded that body posture affects sudomotor functions through both brain and spinal mechanisms.

Adult↗

PubMed1993

Effect of plasma prolactin on sweat rate and sweat composition during exercise in men.

We investigated the role of the exercise-induced elevation of plasma prolactin (PRL) concentration on sweat rate and composition during prolonged exercise in men. Two groups of healthy young males (20-26 yr old) showing a high (high responders; n = 8) or a low (low responders; n = 7) response of plasma PRL concentration to exercise were studied during a 60-min period of exercise on a cycle ergometer (65% maximum O2 consumption) in warm conditions (26.2 +/- 0.1 degrees C; 57 +/- 1% relative humidity), 1 h after receiving 1.25 mg bromocriptine (BRC) per os or a placebo. In high responders, administration of BRC totally abolished the threefold increase in plasma PRL observed in response to exercise with placebo [placebo, 10 +/- 2 (rest) and 30 +/- 2 micrograms/l (exercise); BRC, 9 +/- 1 (rest) and 8 +/- 1 microgram/l (exercise)]. The latter was associated with a significant decrease in sweat rate (2.7 +/- 0.5 to 1.9 +/- 0.3 microliter.cm-2.min-1) and a significant increase in sweat Na+ concentration (57 +/- 7 to 68 +/- 5 mmol/l). BRC also reduced the small response in plasma PRL concentration observed in low responders [placebo, 10 +/- 1 (rest) and 15 +/- 1 microgram/l (exercise); BRC, 9 +/- 1 (rest) and 7 +/- 1 microgram/l (exercise)], but this was not associated with any change in sweat rate (2.2 +/- 0.2 to 1.9 +/- 0.3 microliter.cm-2.min-1) or in sweat Na+ concentration (63 +/- 10 to 64 +/- 9 mmol/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2002

Hepatitis C virus replicates in sweat glands and is released into sweat in patients with chronic hepatitis C.

Hepatitis C virus (HCV) replicates in salivary glands of chronic hepatitis C patients and is released into the saliva, suggesting that HCV may replicate in other exocrine glands. The presence of positive and negative HCV RNA strands was demonstrated by in situ hybridization, and of HCV core protein by immunohistochemistry, in sweat glands and keratinocytes in healthy skin biopsies from 15 patients with chronic hepatitis C and 10 anti-HCV negative patients with chronic liver disease. Positive and negative HCV RNA strands were detected in 9.6 +/- 5.2% and 4.2 +/- 3.8%, respectively, of the epithelial cells of eccrine sweat glands. Core protein was detected in 6.0 +/- 3.93% of these cells. HCV RNA resistant to RNase digestion (encapsidated HCV RNA) was detected in 10/10 sweat samples from HCV-infected patients. Positive and negative HCV RNA strands were detected in 6.7 +/- 2.97% and 3.0 +/- 3.08% of the keratinocytes, respectively. HCV core protein was found in 4.5 +/- 2.76% of these cells. No HCV RNA or HCV core protein was detected in the skin biopsies from the 10 anti-HCV negative patients. In conclusion, HCV replicates in eccrine sweat glands cells and keratinocytes in healthy skin and is released into the sweat.

Adult↗

PubMed1984

Endocrine concomitants of sweating and sweat depression.

The effect of humid heat (Ta = 43 degrees C, Pa = 32 Torr) on sweat rate, plasma renin activity and plasma levels of aldosterone and antidiuretic hormone (ADH) was studied in four male subjects before and after repeated heat exposures. Over-sweating and sweat drippage followed by hidromeiosis were observed in three subjects during initial heat exposure. With repeated humid heat exposures increased sweat rates were accompanied by a more intense sweat depression (hidromeiosis) in all four subjects. In our conditions, no changes in plasma levels of aldosterone and ADH or plasma renin activity were observed with hidromeiosis. Plasma renin activity was slightly depressed by repeated exposures, whereas plasma volumes were enhanced, with no significant changes in plasma Na or K. The results suggest that neither ADH nor the components of the renin-angiotensin aldosterone system are involved in the hidromeiotic phenomenon.

Adult↗

PubMed1993

A comparison of sweating responses during exercise and recovery in terms of sweating rate and body temperature.

Based on the hypothesis that the relation between sweating rate and body temperature should be different during exercise and rest after exercise, we compared the sweating response during exercise and recovery at a similar body temperature. Healthy male subjects performed submaximal exercise (Experiment 1) and maximal exercise (Experiment 2) in a room at 27 degrees C and 35% relative humidity. During exercise and recovery of 20 min after exercise, esophageal temperature (Tes), mean skin temperature, mean body temperature (Tb), chest sweating rate (msw), and the frequency of sweat expulsion (Fsw) were measured. In both experiments, msw and Fsw were clearly higher during exercise than recovery at a similar body temperature (Tes, Tb). msw was similar during exercise and recovery, or a little less during the former, at a similar Fsw. It is concluded that the sweating rate during exercise is greater than that during recovery at the same body temperature, due to greater central sudomotor activity during exercise. The difference between the two values is thought to be related to non-thermal factors and the rate of change in mean skin temperature.

Adult↗

PubMedDate not supplied

Detection of codeine and phenobarbital in sweat collected with a sweat patch.

Six male and two female subjects participated in a clinical study to determine the time course, the cumulative excretion, the intrasubject variability, the influence of site application, and the concentrations of codeine or phenobarbital in sweat following administration of a single dose of the drug. The doses of codeine and phenobarbital were 90 and 100 mg. respectively. Sweat was collected by means of a Sudormed sweat patch. Patches were removed at specified times over 1 week, and the drug content was determined by gas chromatography-mass spectrometry using deuterated internal standards. Codeine was detectable at 1 h following the administration, and a plateau concentration was observed on the third day. The peak codeine concentration was observed during the 12-24-h period. Morphine was never detected in sweat. In contrast, phenobarbital was first observed 3 h after administration, and cumulative excretion was continual throughout the week. Intersubject variability was enormous, as the concentrations for the same dose were in a magnitude of 1-5. Concentrations were in the range of 2-127 and 0.5-33 ng per patch for codeine and phenobarbital, respectively. The influence of the site of patch application was evaluated by analysis of six patches, all removed at the same time (24 h) in two subjects receiving 90 mg codeine. Codeine concentrations differed by a magnitude of 1-3 according to the area of application: the upper arm, the back, and the ribs. These data suggest that the sweat patch technology can be useful for documenting drug use over a 1-week period of surveillance.

Administration, Oral↗

PubMed2006

Equine sweating and anhidrosis Part 1--equine sweating.

Sweating has a variety of functions in mammals including pheromone action, excretion of waste products and maintenance of the skin surface ecosystem. In a small number of mammalian species, which includes humans and the Equidae, it also has an important role in thermoregulation. This review is focused specifically on the thermoregulatory role of sweat in Equidae and the causes of sweating failure (anhidrosis). The first part describes the glandular appearance, sweat composition, and output rates; and considers the latest theories on the glandular control and secretory mechanisms. It is concluded that the glands are not directly innervated but are controlled by the interplay of neural, humoral and paracrine factors. The secretory mechanism is not as simple as previously thought and is mediated by the dynamic interaction of activating pathways, including autocrine control not only of the secretory process but probably also of secretory cell reproduction, growth, and death.

Animals↗

PubMed1994

Influence of lateral posture on sweating: does posture alter the sympathetic outflow to the sweat glands?

Our unpublished observation that a lateral decubitus posture influences the pattern of sweating was systematically tested by measuring galvanic skin resistance (GSR). Changes in the GSR between two electrodes placed on skin was used to quantify the degree of sweating. In the lateral posture, sweating is inhibited on the lower half and stimulated on the upper half and reversal of the lateral posture induces sweating on the opposite half of the body. This observation suggests that the autonomic nervous system is controlled at least in part, by body posture.

Adolescent↗

PubMed1991

Sweat lead levels in persons with high blood lead levels: lead in sweat of lead workers in the tropics.

Samples of blood, sweat and urine were collected from eight control subjects and 19 lead workers in a battery manufacturing factory in the tropics. Sweat samples were collected while workers cycled on a bicycle ergometer at room temperature (27-31 degrees C). All samples were analysed by atomic absorption spectrophotometry. Workers with blood lead levels of 13-36 micrograms dl-1 had sweat levels of 72-256 micrograms l-1 and urinary levels of 28-288 micrograms/g creatinine, while controls had levels of 9-12.2 micrograms dl-1, 9-30 micrograms l-1 and 9-19.6 microgram/g creatinine, respectively. Estimations of sweat lead in lead workers can be masked by skin contamination.

Humans↗