Sweat Volume Research Articles

Calcium, PTH, And CTX Responses to Treadmill Walking During Different Thermal Environments in Older Adults

Serum ionized calcium (iCa) decreases and parathyroid hormone (PTH) and c-terminal telopeptides of type I collagen (CTX; marker of bone resorption) increase during endurance exercise in younger and older adults. Evidence from equine models suggests this may be due to dermal calcium loss. PURPOSE: To determine if exercise in a warm environment exaggerates the decrease in iCa and increases in PTH and CTX compared to a cool environment. METHODS: Women (n=5) and men (n=7) aged 61-78 years performed two identical 1-hour treadmill walking bouts under warm (~28°C) and cool (~21°C) conditions at ~75% of maximal heart rate. iCa, PTH, and CTX were measured every 15 minutes starting 15 minutes before and continuing for 60 minutes after exercise. Sweat calcium loss was estimated from sweat volume and sweat calcium concentration. Changes in iCa, PTH, and CTX were adjusted for plasma volume shifts. Between and within group differences were evaluated using maximum likelihood estimation in a repeated measures model. RESULTS: There was no difference in sweat calcium loss between thermal conditions. iCa decreased similarly during exercise in both conditions (W: -0.16, 95% CI: -0.28, -0.08 mg/dL; C: -0.16, 95% CI: -0.24, -0.04 mg/dL). After adjusting for plasma volume shifts, change in iCaADJ was significant only for the warm condition (-0.24, 95% CI: -0.44, -0.04 mg/dL), but there was no difference between conditions. PTH increased similarly during exercise in both conditions (W: 16.4, 95% CI: 6.2, 26.5 pg/mL; C: 17.3, 95% CI: 8.1, 26.4 pg/mL). Adjusting for plasma volume shifts did not change the results. CTX increased similarly in both conditions (W: 0.08, 95% CI: 0.05, 0.11 ng/mL; C: 0.08, 95% CI: 0.01, 0.16 ng/mL), and adjusting for plasma volume shifts did not change the results. There were no differences between conditions for any outcome, even after adjusting for plasma volume shifts. CONCLUSION: Differing thermal conditions do not appear to be a major factor in the decrease in iCa and the increases in PTH and CTX observed during exercise in older adults. This may be due to the low sweat calcium loss during both conditions or small temperature difference. Future studies should determine if there are sex- or age-related differences that modify the relationship between sweat calcium loss and the activation of bone resorption during exercise.

Wholistic Electrochemical Biosensor for the Combinatorial Detection of Alcohol and Glucose in Perspired Sweat

In this paper, we demonstrate a novel, flexible electrochemical biosensor of the simultaneous detection of glucose and alcohol in perspired human sweat for wearable sensing applications. Evaluation of bodily fluids such as blood, sweat, urine has allowed patients and health-care professionals to track their vital parameters reliably through non-invasive monitoring. Human sweat is one such fluid that contains valuable medical information which can be used to develop real-time, healthcare management devices. Literature studies have shown that sweat alcohol content (SAC) is well correlated to blood alcohol content (BAC). Alcohol consumption modifies blood glucose levels of a diabetic individual depending on their nutrition state inducing either hypoglyceamia or hyperglyceamia. The motivation of this study was to build a sweat based sensor platform for alcohol and glucose management to monitor glucose levels on moderate consumption of alcohol of diabetic social drinkers in low volumes of sweat. The developed sweat biosensor employs a metal- metal oxide electrode stack on a flexible substrate for the non-invasive, low- volume detection of a cohort of glucose and alcohol molecules in sweat through a stable enzyme immunoassay chemistry. Non-faradaic electrochemical impedance spectroscopy (EIS) is the signal transduction mechanism used to detect the presence of glucose and alcohol in sweat. The detection of these molecules is achieved by measuring impedance changes occurring at the electrode- electrolyte interface due to the formation of electrical double layer. Binding events and enzyme catalysis reactions modulate the electrical double layer (EDL) which contribute to the overall impedance change of the system. Detection of sweat glucose levels in the presence of alcohol is demonstrated on the sensor systems at a specific frequency.

Sweat test for cystic fibrosis: Wearable sweat sensor vs. standard laboratory test

BackgroundSweat chloride testing for diagnosis of cystic fibrosis (CF) involves sweat induction, collection and handling, and measurement in an analytical lab. We have developed a wearable sensor with an integrated salt bridge for real-time measurement of sweat chloride concentration. Here, in a proof-of-concept study, we compare the performance of the sensor to current clinical practice in CF patients and healthy subjects. MethodSweat was induced on both forearms of 10 individuals with CF and 10 healthy subjects using pilocarpine iontophoresis. A Macroduct sweat collection device was attached to one arm and sweat was collected for 30 min and then sent for laboratory analysis. A sensor was attached to the other arm and the chloride ion concentration monitored in real time for 30 min using a Bluetooth transceiver and smart phone app. ResultsStable sweat chloride measurements were obtained within 15 min following sweat induction using the wearable sensor. We define the detection time as the time at which the standard deviation of the real-time chloride ion concentration remained below 2 mEq/L for 5 min. The sweat volume for sensor measurements at the detection time was 13.1 ± 11.4 μL (SD), in many cases lower than the minimum sweat volume of 15 μL for conventional testing. The mean difference between sweat chloride concentrations measured by the sensor and the conventional laboratory practice was 6.2 ± 9.5 mEq/L (SD), close to the arm-to-arm variation of about 3 mEq/L. The Pearson correlation coefficient between the two measurements was 0.97 highlighting the excellent agreement between the two methods. ConclusionA wearable sensor can be used to make real-time measurements of sweat chloride within 15 min following sweat induction, requiring a small sweat volume, and with excellent agreement to standard methods.

Decreased thermal sweating of central sudomotor mechanism in African and Korean men.

Tropical natives sweat less and preserve more body fluid than temperate natives, tolerating heat stress. However, the mechanisms involved in such sweating reduction have not been fully elucidated. We examined the sudomotor responses of men of African (n = 36) and Korean (n = 41) ancestry during hot water (43 °C) leg immersion (central sudomotor response). Correlations between mean body temperature, basal metabolic rate (BMR), and sweat rate were also examined. All procedures were done in an automated climate chamber. Local skin temperatures and BMR were measured and mean body temperature was calculated. Sweating activities which include evaporative loss rate, sweat onset time, sweat rate, sweat volume, and whole-body sweat loss volume were examined. In the heat load test, Africans showed lower mean body and local skin temperatures than Koreans before and after heating. Before and after heating, BMR declined significantly in Africans, while that of Koreans declined less. Local sweat onset time increased more in Africans than in Koreans. Local evaporative loss rate, local sweat volume, local sweat rate, and whole body sweat loss volume were reduced in Africans compared with Koreans. There were positive associations of mean body temperature and resting BMR with mean sweat rate. In conclusion, we observed a larger reduction of sudomotor activity in tropical Africans than in temperate Koreans, which was associated with their lower mean body temperature and lower resting BMR.

Patterns of Orthostatic Blood Pressure Changes in Patients with Orthostatic Hypotension.

Background and PurposeThe objective of this study was to determine the patterns of blood pressure (BP) changes during the head-up tilt (HUT) test, particularly in terms of its clinical significance for patients with orthostatic hypotension (OH).MethodsOH was divided into four categories based on systolic BP changes occurring within the first 10 minutes of the HUT test: sustained orthostatic hypotension (SOH), progressive orthostatic hypotension (POH), orthostatic hypotension with partial recovery (OHPR), and transient orthostatic hypotension (TOH).ResultsIn total, 151 patients were analyzed: 65 with SOH, 38 with POH, 21 with OHPR, and 27 with TOH. POH patients exhibited the greatest reduction in systolic BP after HUT and were also the most likely to develop symptoms requiring early termination of the HUT test (42.1%, p<0.001). Additionally, SOH patients exhibited smaller heart-rate variation with deep breathing values (p=0.003) and Valsalva ratios (p=0.022) compared to POH patients. The sweat volume was greatest in OHPR patients.ConclusionsClinical characteristics, including the findings of autonomic function tests, differed between the OH patient groups. This might reflect differences in the underlying pathophysiologic mechanisms. Determining the patterns of BP changes during the HUT test may facilitate the development of effective management strategies in patients with OH.

Study on the effect of professional sports clothing on sports physiology

With the movement of the whole people and the development of competitive sports, the science and technology investment of sports equipment is increasing in each country, and there are a lot of high performance sports clothes with special function. As a kind of high performance sports equipment, wicking professional sports clothing is very popular with athletes and fitness enthusiasts, and its impact on sports physiology is also a hot research topic at home and abroad. Based on this, from the professional sports clothing on the impact of the heat and moisture dissipation, the impact of thermal stress on the exercise physiology was studied, and two sets of professional sports wear of C1 and C2 were designed. The thermal manikin was studied and the analysis of thermal resistance, moisture resistance and permeability index of sports clothing were conducted. Prediction of heat (PHS) model was used to predict and analyse changes of physiological indexes such as skin temperature, sweating rate and total sweat of human body of professional sports clothing and ordinary polo shirt after wearing in five different environments, and the heat regulation effect of professional sports clothing on human body under different environment was obtained. Practice has proved that wearing professional sports clothing can effectively reduce the body’s sweat volume, lower body temperature, prolong the duration of movement.

Effect of Intensive and Repetitive Heat Exposure on the Sudomotor Activity

The sweating response is modulated in two different ways depending on adaptation conditions. In this work, we examined sudomotor activities before and after intensive and repetitive heat exposure. Nine male volunteers were exposed to 30-min half-body immersion in hot water (42 ± 0.5°C) at the same time of day on alternate days for 3 weeks. All experiments were performed in an automated climate chamber. Tympanic (Tty) and skin (Ts) temperatures were measured. Mean body temperature (mTb) was calculated. Sudomotor activities, including sweat onset time, sweat rate and volume, activated sweat gland density (ASGD) and output (ASGO), were tested in four regions of the skin: chest, abdomen, upper back and thigh. Basal Tty and mTb were found to decrease by 0.15°C (P < 0.05) and 0.16°C (P < 0.05), respectively. As a typical data (upper back), sweat onset time increased by 33.6% (P < 0.05) after heat acclimation. After heat acclimation, sweat rate decreased by 14.7% (P < 0.05), sweat volume decreased by 15.5% (P < 0.05) and ASGO also decreased by 11.1% (P < 0.05). ASGD decreased by 4.1% after heat acclimation without statistical significance. The data suggest that intensive and repetitive heat exposure induces suppression of sudomotor activities within 3 weeks.

A Wearable Electrochemical Sensor to Monitor Progression of Wound Healing

An enzymatic electrochemical biosensor comprising the enzyme, urate oxidase (uricase, UOx), has been investigated for detection of real-time changes in uric acid. Uric acid is a key biomarker for monitoring severity of wounds, a complex process initiated to restore tissue damage.1 Although, tracking wound healing continues to be a challenge in healthcare; it is equally demanding. In existing technology, the time taken from the appearance of a wound to the commencement of an effective wound management plan can be lengthy, as laboratory tests can take days to complete. With its presence in different bio-fluids2, this work explores the continuous monitoring of systemic uric acid in human sweat. Electrochemical techniques like cyclic voltammetry and differential pulse voltammetry have been investigated for evaluating the success of the sensor on a wearable platform as a surrogate for wound healing. On this biosensor, hydrolysis of UA was monitored to detect the oxidation of its byproduct, H2O2. Results show that the use of a redox electron shuttle such as ferrocene carboxylic acid (FCA) or metal nano-particles enable electron transfer between the active site of the enzyme and the electrode. This work explores the possibilities of embedding the biosensor in wound dressing-gauze materials as substrates and investigates the effect and role of metal nano-particles on detection. It can measure very low volumes (0.5uL) of sweat showing that such low volumes are sufficient for systemic detection of uric acid at the wound vicinity. This non-invasive approach holds promise for tracking wound chronicity and can be beneficial towards shorter hospitalization time, costs and reduced outcomes of trauma, surgery, and amputations.3 The developed biosensor could facilitate treatment with an improved, comprehensive understanding of the recovery processes associated with healing.

An Endurance Athlete's Self-Report of a Novel Method for Sweat Sodium Measurement in the Field

Hypovolemia and reduced blood sodium levels have been reported in some athletes. Sweat sodium concentration has been shown to be directly proportional to percent plasma volume loss and, therefore, may serve as useful proxy indicator of hypovolemia. This case, a 44-year old male physician with ten years of experience in long distance triathlons and endurance racing, reports himself to be a salty, heavy sweater; has noted significant weight loss during some competitions; and, occasionally, encounters symptoms that could be attributed to hypovolemia, despite drinking to thirst. This case relates his attempts to measure sweat sodium concentration using regional patches and two tools, the Horiba LAQUA twin B-721 Compact Salt Meter and the AquaChek strip (from the swimming pool industry) as compared to a pilocarpine test using a standard approved by the Cystic Fibrosis Foundation. Both tools yielded comparable results, with wide variation in sweat sodium concentration across the samples. The AquaChek showed a consistent bias of -4.16 sodium mEq/L compared to the Horiba. Both are comparable to a pilocarpine standard and validity and reliability of each method was robust when later tested against standard saline solutions. In this case, ease of application, sufficient sweat volume, and potentially reduced contamination from body hair suggest this site for further evaluation of sweat sodium in the field. Additionally, compared to laboratory testing, each method is cost efficient.

A device to measure secretion of individual sweat glands for diagnosis of peripheral neuropathy.

There is a need for quantitative, precise assessment of small fiber peripheral nerve function. We tested a customized camera device and protocol designed to quantify secretions of individual sweat glands (SGs). Testing was performed on 178 healthy controls and 20 neuropathy subjects. Sweating was stimulated on a 2.25 cm2 skin area by iontophoresis of pilocarpine. The camera imaged sweat from 50 to 400 sweat ducts. We calculated secretion rate of individual SGs, total sweat volume, and number of secreting SGs at four body sites. Neuropathy subjects were tested at the two distal sites to demonstrate the device's capability to detect abnormal sudomotor function. Normal ranges were calculated for each body site. Neuropathy subjects had lower sweat rates per SG, lower total sweat, and lower SG density. The normal values decreased with advancing age, were lower in females, and differed between body sites. There was good agreement with repeat testing. The device provides reliable, precise quantitative measures of sweat secretion from single SGs for characterization of sudomotor nerve function in healthy control subjects and in subjects with known peripheral neuropathy. The test combines the capabilities of existing tests of sudomotor function while providing additional capabilities.

Thin, Soft, Skin-Mounted Microfluidic Networks with Capillary Bursting Valves for Chrono-Sampling of Sweat.

Systems for time sequential capture of microliter volumes of sweat released from targeted regions of the skin offer the potential to enable analysis of temporal variations in electrolyte balance and biomarker concentration throughout a period of interest. Current methods that rely on absorbent pads taped to the skin do not offer the ease of use in sweat capture needed for quantitative tracking; emerging classes of electronic wearable sweat analysis systems do not directly manage sweat-induced fluid flows for sample isolation. Here, a thin, soft, "skin-like" microfluidic platform is introduced that bonds to the skin to allow for collection and storage of sweat in an interconnected set of microreservoirs. Pressure induced by the sweat glands drives flow through a network of microchannels that incorporates capillary bursting valves designed to open at different pressures, for the purpose of passively guiding sweat through the system in sequential fashion. A representative device recovers 1.8 µL volumes of sweat each from 0.8 min of sweating into a set of separate microreservoirs, collected from 0.03 cm2 area of skin with approximately five glands, corresponding to a sweat rate of 0.60 µL min-1 per gland. Human studies demonstrate applications in the accurate chemical analysis of lactate, sodium, and potassium concentrations and their temporal variations.

Demonstration of autonomic dysfunction in traumatic brachial plexus injury using quantitative sudomotor axon reflex test: Preliminary results.

To objectively document autonomic dysfunction in the affected arm with traumatic brachial plexus injury (TBPI) using quantitative sudomotor axon reflex test (QSART). Patients with TBPI presenting to the neurosurgical outpatient department from August 2013 to November 2014 were included in the study. The QSART was administered to each patient with prior informed consent detailing the procedure. A total of 20 patients with TBPI were included in the study. The age, sex, mode of injury, date of injury, side of injury, and type of injury (pan brachial plexus vs preserved distal function) were recorded. The presence of any pain was also recorded. The injuries were also grouped as preganglionic and postganglionic injuries based on clinical, electroneuromyography (ENMG) and magnetic resonance imaging (MRI) findings. The results of the test for the affected and normal limb were recorded and analyzed with appropriate statistical tests to determine any significant differences. The study included 20 patients, with their age ranging from 15 to 50 years. Out of the 20 patients, one was female and the rest 19 were males. Seven (35%) of the injuries were complete (pan brachial plexus) and 13 (65%) were incomplete (preserved distal function). All patients had preganglionic TBPI. There was no evidence of any statistically significant difference between the affected and normal arm for total sweat volume (P = 0.20) and latency period (P = 0.42). However, the average mean values for the same were lower in the affected arm as compared to the normal. The baseline sweat output (P = 0.010), however, was significantly lower in the affected arm as compared to the normal arm. QSART has demonstrated reduced baseline sweat output in the affected arm in patients with TBPI. This indicates the presence of autonomic dysfunction in the injured arm.

Sweat Facilitated Amino Acid Losses in Male Athletes during Exercise at 32-34°C.

Sweat contains amino acids and electrolytes derived from plasma and athletes can lose 1-2L of sweat per hour during exercise. Sweat may also contain contributions of amino acids as well as urea, sodium and potassium from the natural moisturizing factors (NMF) produced in the stratum corneum. In preliminary experiments, one participant was tested on three separate occasions to compare sweat composition with surface water washings from the same area of skin to assess contributions from NMF. Two participants performed a 40 minute self-paced cycle session with sweat collected from cleansed skin at regular intervals to assess the contributions to the sweat load from NMF over the period of exercise. The main study investigated sweat amino acid composition collected from nineteen male athletes following standardised endurance exercise regimes at 32–34°C and 20–30% RH. Plasma was also collected from ten of the athletes to compare sweat and plasma composition of amino acids. The amino acid profiles of the skin washings were similar to the sweat, suggesting that the NMF could contribute certain amino acids into sweat. Since the sweat collected from athletes contained some amino acid contributions from the skin, this fluid was subsequently referred to as “faux” sweat. Samples taken over 40 minutes of exercise showed that these contributions diminished over time and were minimal at 35 minutes. In the main study, the faux sweat samples collected from the athletes with minimal NMF contributions, were characterised by relatively high levels of serine, histidine, ornithine, glycine and alanine compared with the corresponding levels measured in the plasma. Aspartic acid was detected in faux sweat but not in the plasma. Glutamine and proline were lower in the faux sweat than plasma in all the athletes. Three phenotypic groups of athletes were defined based on faux sweat volumes and composition profiles of amino acids with varying relative abundances of histidine, serine, glycine and ornithine. It was concluded that for some individuals, faux sweat resulting from exercise at 32–34°C and 20–30% RH posed a potentially significant source of amino acid loss.

Thermoregulation in boys and men exercising at the same heat production per unit body mass.

Child-adult thermoregulatory comparisons may be biased by differences in metabolic heat production ([Formula: see text]). We compared thermoregulatory responses of boys and men exercising at two intensities prescribed to elicit either a fixed [Formula: see text] per unit body mass (BM) or a fixed absolute [Formula: see text]. Ten boys (10-12 years) and 10 men (19-25 years) performed 4×20-min cycling at a fixed [Formula: see text] per BM (Wkg(-1)) at 35°C and 35% relative humidity (MENREL). Men also cycled (MENABS) at the same absolute [Formula: see text] (in W) as the boys. [Formula: see text] was lower in boys compared with MENREL, but similar to MENABS (mean±SD, 233.6±38.4, 396.5±72.3, 233.6±34.1W, respectively, P<0.001). Conversely, [Formula: see text] per unit BM was similar between boys and MENREL, and lower in MENABS (5.7±1.0, 5.6±0.8 and 3.3±0.3Wkg(-1), respectively; P<0.001). The change in rectal temperature was similar between boys and MENREL (0.6±0.2 vs. 0.7±0.2°C, P=0.92) but was lower in MENABS (0.3±0.2°C, P=0.004). Sweat volume was lower in boys compared to MENABS (500±173 vs. 710±150mL; P=0.041), despite the same evaporative heat balance requirement (E req) (199.1±34.2 vs. 201.0±32.7W, P=0.87). Boys and men demonstrated similar thermoregulatory responses to 80min of exercise in the heat performed at a fixed [Formula: see text] per unit BM. Sweat volume was lower in boys compared to men, despite similarities in absolute [Formula: see text] and E req.

Physiological And Perceptual Response Of Drinking Vs Mouth Rinsing With Water During A 15-km Running Time Trial

PURPOSE: This study examined the effects of ingesting versus mouth rinsing with water during a running time trial. METHODS: Recreationally active female runners (n = 23; 26 ± 6 y; 22 ± 3 % body fat) completed two, 15-km time trials on an outdoor course (~20°C; 87% RH) in a randomized cross-over study design. Participants consumed 355 ml of water (CW) or mouth rinsed (MR) with water every 3-km for 5 s. Completion time, HR, RPE, sweat loss, pre-and post-run ratings of perceived thirst, and gut fullness were measured. RESULTS: Sweat losses were greater (p = 0.01) for CW (1.6 ± 0.6 L) compared to MR (1.2 ± 0.3 L), however did not alter performance (79.8 ± 7.0 min and 79.7 ± 7.1 min, p = 0.64), HR (181 ± 15 and 179 ±13 bpm, p = 0.44), or RPE (16 ± 2 and 16 ± 2, p = 0.97). Perceived thirst did not differ before run (3.6 ± 1.8 and 4.1 ± 1.5 for CW and MR), but was higher (p = 0.02) for MR (6.8 ± 1.1) compared to CW (5.8 ± 2.0) post-run. No difference in post-run GF (5 ± 1.7 and 4.7 ± 1.4, p = 0.85, for CW and MR) was observed. CONCLUSION: MR may reduce sweat volume versus CW when running for >1 h in temperate and humid environments, but does not impair performance or induce significant cardiovascular drift in female runners who begin exercise euhydrated. A MR strategy may reduce gastrointestinal distress for runners who do not like drinking during runs and allow for a reduction in volume of water carried.

‘SWEATCH’: A Wearable Platform for Harvesting and Analysing Sweat Sodium Content

AbstractA platform for harvesting and analysing the sodium content of sweat in real time is presented. One is a ‘watch’ format in which the sampling and fluidic system, electrodes, circuitry and battery are arranged vertically, while in the other ‘pod’ format, the electronics and battery components, and the fluidics electrodes are arranged horizontally. The platforms are designed to be securely attached to the skin using a velcro strap. Sweat enters into the device through a sampling orifice and passes over solid‐state sodium‐selective and reference electrodes and into a storage area containing a high capacity adsorbent material. The liquid movement is entirely driven by capillary action, and the flow rate through the device can be mediated through variation of the width of a fluidic channel linking the electrodes to the sample storage area. Changing the width dimension through 750, 500 and 250 µm produces flow rates of 38.20, 21.48 and 6.61 µL/min, respectively. Variation of the sweat uptake rate and the storage volume capacity enables the duration of usage to be varied according to the needs of the user. The devices can be easily disassembled to replace the electrodes and the high capacity adsorbant material. The storage sweat is available for subsequent measurement of the total volume of sweat harvested and the average concentration of sodium over the period of use. Signals generated by the electrodes are passed to a custom designed electronics board with high input impedance to accurately capture the voltage. The real‐time data is transmitted wirelessly using incorporated Bluetooth circuitry to a remote basestation (laptop, mobile phone, tablet) for data visualization and storage in standard formats. Results obtained during trials over a period of ca. 30 minutes controlled exercise are consistent with previously published data, showing a gradual relatively slow increase of the sodium concentration in the sweat during this period.

Long-term outcomes with agalsidase alfa enzyme replacement therapy: Analysis using deconstructed composite events

Anecdotal reports suggest that the currently approved dosing interval of agalsidase alfa (0.2 mg/kg/2 weeks) for Fabry disease treatment is too long. This randomised, double-blind, placebo-controlled, crossover study investigated three altered dosing intervals. 18 Fabry patients received three agalsidase alfa dosing schedules, each for four weeks (A: 0.2 mg/kg ∗ 2 weeks, B: 0.1 mg/kg/week, C: 0.2 mg/kg/week). Health state, pain levels, sweat volume and latency and plasma and urinary globotriaosylceramide levels were recorded throughout the study. No significant differences were found among the schedules for the primary efficacy outcome of self-assessed health state, or for pain scores. A trend toward increased sweat volume on QSART testing, and reduced urine globotriaosylceramide concentration were seen with treatment schedule C. Agalsidase alfa was safe and well tolerated with all schedules. In conclusion, the primary analyses did not find weekly infusions of agalsidase alfa to be statistically better than the approved dosing schedule however the data indicates that further studies with more patients over a longer period are required to more accurately determine the optimum dose and schedule.

Sweat Potassium Decreases with Increased Sweating in Perimenopausal Women

Objective: To investigate the relationship between rate of sweat production and sweat potassium concentration in premenopausal (PreM), perimenopausal (PeriM) and postmenopausal (PostM) women after a moderate exercise. Study Design: This is a cross-sectional study conducted in May 2012 at the Department of Physiology, University of Benin, Nigeria. Methods: Thirty healthy female volunteers comprising of PreM (aged: 22.5±0.8 yrs, n = 10), PeriM (aged: 46.5±1.1 yrs, n = 10), and PostM (aged: 52.2±0.9 yrs, n=10) participated in the study. Sweat was obtained with a sweat suction apparatus from a 120 cm circular area marked on the skin of the face and neck after a 15 min walk on a calibrated treadmill at a speed of 4.2 km/h at 27°C and a relative humidity of 85-95%, followed by measurement of sweat volume (SV) and [K]. Sweat rate (SR) was determined by dividing the volume of sweat produced by the duration of exercise. Thirst perception (TP) was self-rated using the Visual Analogue Scale (VAS). Original Research Article Amabebe et al.; BJMMR, 14(2): 1-10, 2016; Article no.BJMMR.23890 2 Results: The PeriM women demonstrated higher SR (ml/min) (P = .01) and SV (ml) (P = .0006) compared to women in the other groups: SR (PeriM = 0.12±0.01; PreM = 0.07±0.02; PostM = 0.06±0.01), and SV (PeriM = 1.7±0.2; PostM = 0.9±0.1). However, they had lower sweat [K] (mmol/l) (P = .04), compared to their PostM counterparts (PeriM = 19.98±1.5; PostM = 24.90±1.8). Furthermore, sweat [K] was inversely associated with SR (r = -0.4, P = .02). Also, change in TP (cm) was highest (P = .001) in the PeriM women (PeriM = 2.5±0.2; PreM = 2.1±0.3; PostM = 0.99±0.2). Conclusion: Although excessive sweating can lead to depletion of the body's potassium concentration, the sweat potassium concentration decreases with increased sweating especially in perimenopausal women. This requires further investigation, as it could be an adaptive mechanism inhibiting excessive potassium loss.

Traditional Japanese Style Bathing May Contribute to Good Health and Longevity

The objective of this study was to determine how traditional Japanese style bathing could promote good health. Using healthy volunteers, we assessed body temperature (core and cutaneous), red blood cells, white blood cells (WBCs), venous blood gas parameters (PO2, SO2, PCO2, TCO2, HCO3, and pH), weight loss (which may indicate sweat volume), and the time until sweating before and after bathing. We simultaneously conducted a double-blind clinical trial using a bath additive group and a control group to investigate the effect of a bath additive on the same parameters. We found that bathing increased the core and cutaneous body temperature, as well as PO2, SO2, and blood pH. All of the subjects also showed increases in heart rate and weight loss (sweat volume). After bathing, the number and ratio of granulocytes increased while the number and ratio of lymphocytes decreased. These results tended to be emphasized in the bath additive group; however, significant between-group differences were not detected. Our results indicated that bathing improved blood circulation and had a modulatory effect on the autonomic nervous system. This suggested that traditional Japanese style bathing might contribute to good health and longevity; however, additional larger-scale studies were needed to confirm or refute this conclusion.

Old and New Approaches for Assessing Sweating.

The evaluation of sweating activities contributes to both medical services and social living. There are several old and new approaches for assessing sweating. These methods are mainly composed of adopted techniques that focus on detecting small amounts of water on the skin surface. For many years, the iodine-starch reaction has been applied in various settings to evaluate sweat on the skin surface. However, methodology based on the coloration of sweat is in a constant state of evolution, and multiple advancements have been made. Furthermore, common fingerprinting is not just used for obtaining personal-identifying information anymore as it can also provide scientifically important information for sweat-pore mapping and sweat-component analysis. Additionally, there are multiple techniques for the quantitative measurement of sweat volume and dynamic intravital imaging of sweat, and these are also continually evolving. This chapter provides an overview of the old and new approaches for assessing sweating.