Sweat Electrolyte Concentrations Research Articles

Effect Of Hydration Status On Acute Changes In Sweat Electrolyte And Cortisol Concentrations During Exercise

Effect Of Hydration Status On Acute Changes In Sweat Electrolyte And Cortisol Concentrations During Exercise

Hybrid microstructure-based stretchable biosensors for multi-physiological signal sensing

Wearable biosensors provide continuous, real-time physiological monitoring of biochemical markers in biofluids such as sweat, tears, saliva, and interstitial fluid. However, achieving high stretchability and stable biochemical signal monitoring remains challenging. Here, we propose a hybrid microstructure (HMS) strategy to fabricate highly stretchable multifunctional biosensors capable of detecting sweat electrolyte concentrations, pH levels, and surface electromyography (EMG) signals. By integrating a HMS, stable conductivity under large strains is ensured. Stretching tests up to 5000 cycles demonstrated the electrodes’ stretchable stability and reliability. The high-performance electrodes were used for EMG monitoring on human skin. Additionally, active materials were coated onto the stretchable electrodes to create multifunctional sweat sensors capable of monitoring pH as well as calcium, sodium, and potassium ions (Ca2+, Na+, K+). The electrodes reliably maintained their functionality under 60% strain, providing new insights into the fabrication of stable, highly stretchable biosensors.

Mild dehydration does not alter acute changes in sweat electrolyte concentrations during exercise.

The purpose of this study was to determine the effect of hydration status on the change in sweat sodium (Na+), chloride (Cl-), and potassium (K+) concentrations during exercise-heat stress. Fifteen subjects (Six female, nine male; 29 ± 9 y; 71 ± 14 kg) completed 90 min of cycling (81% HRmax) in the heat (~33°C, 42% rh) with fluid replacement to maintain euhydration (EUH) or without fluid to dehydrate to 2.4 ± 0.4% body mass loss (DEH). Sweat was collected from the forehead (FH), right scapula (SCAP), and left (LVFA) and right (RVFA) ventral forearms using the absorbent pad technique at the beginning (0-30 min) and end of exercise (60-90 min). Sweat was analyzed for Na+, Cl-, and K+ concentrations using ion chromatography. Data are reported as mean ± SD or median ± IQR. There were no differences (Paired t-tests or Wilcoxon signed-rank tests) between EUH and DEH in the change in sweat Na+ (FH: 24.3 ± 21.5 vs. 30.8 ± 22.4 mmol/L; SCAP: 9.7 ± 6.2 vs. 9.6 ± 8.2 mmol/L; LVFA: 7.5 ± 6.0 vs. 5.6 ± 5.9 mmol/L; RVFA: 8.2 ± 8.6 vs. 7.8 ± 5.2 mmol/L), sweat Cl-, or sweat K+ at any site (p = 0.07-0.99). The change in sweat electrolyte concentrations during 90 min of exercise in the heat was not significantly influenced by mild dehydration in recreational to moderately-trained male and female athletes.

How Elite Athletes with a Spinal Cord Injury Sweat during Exercise-An Exploratory Study.

Sweat and thermal responses in individuals with spinal cord injury (SCI) are impaired depending on lesion characteristics. This is particularly problematic for athletes and may ultimately lead to reduced performance. This exploratory study investigated the feasibility of field-usable methods to objectively collect data relevant to sweat response in elite athletes with SCI. Differences in sweat response were also evaluated for different athlete characteristics. Measurements were performed during exercise and included core temperature (Tc), heart rate, urine specific gravity, fluid intake, sweat rate, and sweat electrolyte concentration. Differences for sex, lesion level (tetraplegia versus paraplegia), motor impairment (complete versus incomplete), and sport type (endurance versus team/skill) were evaluated. Fifteen athletes (median (Q1-Q3) age, 30 (28-36) years; three females; 11 with complete lesions) were included. Endurance athletes were measured during indoor performance tests (n = 10), whereas team/skill athletes were measured during training sessions (n = 5). In the mixed exercise intensities, the average Tc was 37.7 (37.3-37.8) °C and the average heart rate was 126 (100-146) bpm. Dehydration, defined as a urine specific gravity > 1.020 ng/mL, was prevalent in six athletes before exercise and in five athletes after exercise. The sweat rate was lower in athletes with tetraplegia (p = 0.02) and in team/skill athletes (p = 0.008). Collecting sweat and thermal response data from athletes with SCI in the field is feasible. Given the suboptimal hydration status of many athletes, raising awareness of the importance of hydration seems valuable.

How elite athletes with a spinal cord injury sweat - An exploratory observational study

Introduction
 Sweat response and thermoregulation in individuals with spinal cord injury (SCI) may be impaired depending on the level and completeness of the lesion (Grossmann et al., 2021; Price, 2006). This is particularly problematic for athletes and may ultimately lead to decreased performance. This exploratory observational study collected data on sweat response in elite athletes with SCI during exercise. We also explored the feasibility of collecting these data in the field.
 Methods:
 Elite athletes with SCI were measured during indoor performance tests (n = 10) or training sessions (n = 5). Parameters collected included core body temperature (Tc), heart rate, urine specific gravity, fluid intake, sweat rate, and sweat electrolyte concentration. Differences in parameters were evaluated for sex, lesion level (tetraplegia versus paraplegia), motor impairment (complete versus incomplete), and sport type (endurance versus team/skill).
 Results
 15 athletes (median (Q1-Q3) age 30 (28-36) years, three females, 11 with a complete lesion) were included. Measurements could be successfully performed on most athletes. Average Tc was 37.7 (37.3-37.8) °C and average heart rate 126 (100-146) bpm. Dehydration, defined as a urine specific gravity > 1.020 ng/ml, was prevalent in six athletes before exercise and in five athletes after exercise. Fluid intake and electrolyte concentrations were similar between groups. Sweat rate was lower in athletes with a tetraplegia (-0.04 (-0.23-0.37) versus 0.51 (0.38-0.73) l/h, p = 0.02, r = 0.60) and in team/skill athletes (0.12 (-0.13-0.33) versus 0.52 (0.42-0.73) l/h, p = 0.008, r = 0.68).
 Discussion/Conclusion
 The measurement methods used in this study are straightforward and relatively easy to perform in the field. Our results suggest that there is room for improvement in the hydration status of elite athletes with SCI, especially prior to exercise. Optimization of fluid intake and thermoregulation requires personalized strategies based on lesion characteristics and type of sport.
 References
 Grossmann, F., Flueck, J. L., Perret, C., Meeusen, R., & Roelands, B. (2021). The thermoregulatory and thermal responses of individuals with a spinal cord injury during exercise, acclimation and by using cooling strategies – A systematic review. Frontiers in Physiology, 12, Article 636997. https://doi.org/10.3389/fphys.2021.636997
 Price, M. J. (2006). Thermoregulation during exercise in individuals with spinal cord injuries. Sports Medicine, 36(10), 863-879. https://doi.org/10.2165/00007256-200636100-00005

Fabrication and characterization of chemiresistive CuO sensors sensitized by Ca-doping for detection of sweat electrolyte concentration

Intense electrolyte loss as a result of excessive sweating can disrupt the electrolyte balance in the body and cause damage to many organs, as well as potentially fatal disturbances in even brain functions. There are commercial sensors developed to monitor users' physical activity, however, few of them can provide information on users' health status through sweat analysis. Herein we report a chemiresistive sensor to monitor the sweat electrolyte concentration level. Metal oxide semiconducting CuO films were deposited on Au electrodes as sensing layers. Ca2+ ions were doped into the CuO lattice as sensitizer. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and UV–Vis spectroscopy were used to characterize the films. Sensors produced with pure and Ca-doped CuO films were tested against different concentrations of artificial sweat. The sensors responded well to sweat electrolyte concentration with a linear detection range of 20–80 mM. Detection limits between 6.64 and 9.86 mM were estimated using standard deviation methods. Average sensor response times were found to be 12 s.

Measurement Compensation Method for Wearable Microfluidic Sweat Sensors Toward Monitoring a Wide Range of Local Sweat Rates and Electrolyte Concentration

Measurement Compensation Method for Wearable Microfluidic Sweat Sensors Toward Monitoring a Wide Range of Local Sweat Rates and Electrolyte Concentration

No Effect Of Tattoos On Local Sweating Rate Or Sweat Electrolyte Concentrations During Exercise

No Effect Of Tattoos On Local Sweating Rate Or Sweat Electrolyte Concentrations During Exercise

An unconventional vertical fluidic-controlled wearable platform for synchronously detecting sweat rate and electrolyte concentration

Epidermal microfluidic devices with long microchannels have been developed for continuous sweat analysis, which are crucial to assess personal hydration status and underlying health conditions. However, the flow resistance in long channels and the ionic concentration variation significantly affect the accuracy of both the sweat rate and electrolyte concentration measurements. Herein, we present a novel fluidic-controlled wearable platform for synchronously dropwise-detecting the sweat rate and total electrolyte concentration. The unconventional platform consisting of a vertically shortened channel, a pair of embedded electrodes and an absorption layer, is designed to minimize the flow resistance and transform sweat fluidics into uniform micro-droplets for chronological and dropwise detection. Real-time sweat conductance is decoupled from a square-wave-like curve, where the sweat rate and electrolyte concentration can be derived from the interval time and peak value, respectively. Flexible and wearable band devices are demonstrated to show their potential application for hydration status assessment during exercises.

Wearable Microfluidic Sensor for the Simultaneous and Continuous Monitoring of Local Sweat Rates and Electrolyte Concentrations.

Temperature elevation due to global warming increases the risks of dehydration, which can induce heat-related illness. Proper rehydration with appropriate amounts of water and electrolytes is essential to aid body fluid homeostasis. Wearable sweat sensors which can monitor both the sweat rate and sweat electrolyte concentration may be an effective tool for determining appropriate rehydration. Here, we developed a novel potentially wearable sensor that can monitor both the local sweat rate and sweat electrolyte concentration continuously. The new device includes a system with a short microfluidic pathway that guides the sweat appearing on the skin to a small space in the device to form a quantifiable droplet. The sweat rate is assessed from the time for the droplet to appear and droplet volume, while an integrated electric sensor detects the sodium chloride concentration in each sweat droplet. We demonstrated that this new device could record both the flow rates of artificial sweat and its sodium chloride concentration in ranges of human sweating with an accuracy within ±10%. This is equivalent to the accuracy of commercially available sweat rate meters and sweat ion sensors. The present study provides a new perspective for the design of wearable sensors that can continuously monitor sweat rates and sweat electrolyte concentrations for potential application to a healthcare device.

NCAA Division I American football players with sickle cell trait have altered hematological responses and hydration status

Sickle cell trait (SCT) is a risk factor of collapse and sudden death in athletes. We conducted a longitudinal study to determine the hematological responses and hydration status in NCAA Division I American football players with SCT. The study took place over 2 years with 6 SCT and 6 position-matched controls (CON) in year 1; and 4 SCT and 4 CON in year 2. In year 2, three of the four SCT players were recruited and re-enrolled with new position-matched controls (total sample data = 10 SCT and 10 CON). Blood samples were taken at three visits: pre-camp, post-camp, and post-season to examine hemoglobin variants, complete blood counts, and chemistry panel 26. Hydration status was assessed by measuring body weight change, urine specific gravity, and urine and sweat electrolyte concentrations during the pre-season training camp. All SCT players were confirmed to have SCT (HbS = 37.9 ± 2.4%) and had greater red cell distribution width (RDW) compared to CON across all visits. Serum uric acid was higher in SCT (7.3 ± 1.0 mg/dL) compared to CON (6.1 ± 0.6 mg/dL; p = 0.001). Furthermore, serum creatine kinase levels were greater in SCT (1617.0 ± 1034.8 IU/L) at pre-camp compared to CON (1037.4 ± 602.8 IU/L; p = 0.03). SCT players exhibited lower pre- and post-practice urine electrolytes and urine specific gravity (SCT pre: 1.019 ± 0.005 vs. CON pre: 1.026 ± 0.008 p < 0.001; SCT post: 1.020 ± 0.005 vs. CON post: 1.030 ± 0.008 p < 0.01), whereas sweat sodium concentrations were higher in SCT players (55.4 ± 13.6 mmol/L) compared to CON (45.5 ± 10.6 mmol/L; p < 0.001). Given the evidence, greater uric acid and CPK levels in SCT players compared to CON may be an early indicator of altered kidney function and muscle damage, which could be added into NCAA guidelines for surveillance among SCT players. Consistent education and reinforcement of the importance of adequate fluid balance during exercise are critical for both SCT and CON players.

Effects of Field Position on Fluid Balance and Electrolyte Losses in Collegiate Women's Soccer Players.

Background and objectives: Research investigating hydration strategies specialized for women’s soccer players is limited, despite the growth in the sport. The purpose of this study was to determine the effects of fluid balance and electrolyte losses in collegiate women’s soccer players. Materials and Methods: Eighteen NCAA Division I women’s soccer players were recruited (age: 19.2 ± 1.0 yr; weight: 68.5 ± 9.0 kg, and height: 168.4 ± 6.7 cm; mean ± SD), including: 3 forwards (FW), 7 mid-fielders (MD), 5 defenders (DF), and 3 goalkeepers (GK). Players practiced outdoor during spring off-season training camp for a total 14 practices (WBGT: 18.3 ± 3.1 °C). The main outcome measures included body mass change (BMC), sweat rate, urine and sweat electrolyte concentrations, and fluid intake. Results: Results were analyzed for comparison between low (LOW; 16.2 ± 2.6° C, n = 7) and moderate risk environments for hyperthermia (MOD; 20.5 ± 1.5 °C, n = 7) as well as by field position. The majority (54%) of players were in a hypohydrated state prior to practice. Overall, 26.7% of players had a %BMC greater than 0%, 71.4% of players had a %BMC less than −2%, and 1.9% of players had a %BMC greater than −2% (all MD position). Mean %BMC and sweat rate in all environmental conditions were −0.4 ± 0.4 kg (−0.5 ± 0.6% body mass) and 1.03 ± 0.21 mg·cm−2·min−1, respectively. In the MOD environment, players exhibited a greater sweat rate (1.07 ± 0.22 mg·cm−2·min−1) compared to LOW (0.99 ± 0.22 mg·cm−2·min−1; p = 0.02). By position, DF had a greater total fluid intake and a lower %BMC compared to FW, MD, and GK (all p < 0.001). FW had a greater sweat sodium (Na+) (51.4 ± 9.8 mmol·L−1), whereas GK had the lowest sweat sodium (Na+) (30.9 ± 3.9 mmol·L−1). Conclusions: Hydration strategies should target pre-practice to ensure players are adequately hydrated. Environments deemed to be of moderate risk of hyperthermia significantly elevated the sweat rate but did not influence fluid intake and hydration status compared to low-risk environments. Given the differences in fluid balance and sweat responses, recommendations should be issued relative to soccer position.

Sweat Characteristics of Cramp-Prone and Cramp-Resistant Athletes.

Exercise-associated muscle cramps (EAMCs) are thought to be caused by dehydration and/or electrolyte losses. In this multicenter, cross-sectional study, the authors determined whether sweat rates (SRs), sweat electrolyte concentrations, or sweat electrolyte content differed in athletes with (i.e.,crampers) and without (i.e.,noncrampers) a history of EAMCs and whether these variables could predict EAMC-prone athletes. Male and female collegiate athletes (N = 350) from 11 sports with (n = 245) and without (n = 105) a self-reported history of EAMCs completed a typical exercise or conditioning session. SRs, calculated from body mass, and posterior forearm sweat were analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl-]sw). The authors used SRs and sweat electrolyte concentrations to calculate sweat electrolyte content lost. Within each gender, no differences in SRs (204 males, p = .92; 146 females, p = .24); [Na+]sw (191 males, p = .55; 126 females, p = .55); Na+sw content (191 males, p = .59; 126 females, p = .20); [K+]sw (192 males, p = .57; 126 females, p = .87); K+sw content (192 males, p = .49; 126 females, p = .03); [Cl-]sw (192 males, p = .94; 77 females, p = .57); and Cl-sw content (192 males, p = .55; 77 females, p = .34) occurred between crampers and noncrampers. Receiver operating characteristic curve analysis revealed that sweat electrolyte content and SRs were predictive of EAMC-prone athletes in American football (area under curve = 0.65-0.72, p ≤ .005), but not in any other sport. EAMCs may not be solely caused by fluid or electrolyte losses in most athletes. Fluid and electrolyte replacement may help American footballers. Clinicians should individualize fluid and electrolyte replacement and understand different etiologies for EAMCs.

Comparison of Skin Cleaning Methods for Measurement of Regional Sweat Electrolyte Concentrations

Comparison of Skin Cleaning Methods for Measurement of Regional Sweat Electrolyte Concentrations

Body map of regional vs. whole body sweating rate and sweat electrolyte concentrations in men and women during moderate exercise-heat stress.

This study determined the relations between regional (REG) and whole body (WB) sweating rate (RSR and WBSR, respectively) as well as REG and WB sweat Na+ concentration ([Na+]) during exercise. Twenty-six recreational athletes (17 men, 9 women) cycled for 90 min while WB sweat [Na+] was measured using the washdown technique. RSR and REG sweat [Na+] were measured from nine regions using absorbent patches. RSR and REG sweat [Na+] from all regions were significantly ( P < 0.05) correlated with WBSR ( r = 0.58-0.83) and WB sweat [Na+] ( r = 0.74-0.88), respectively. However, the slope and y-intercept of the regression lines for most models were significantly different than 1 and 0, respectively. The coefficients of determination ( r2) were 0.44-0.69 for RSR predicting WBSR [best predictors: dorsal forearm ( r2 = 0.62) and triceps ( r2 = 0.69)] and 0.55-0.77 for REG predicting WB sweat [Na+] [best predictors: ventral forearm ( r2 = 0.73) and thigh ( r2 = 0.77)]. There was a significant ( P < 0.05) effect of day-to-day variability on the regression model predicting WBSR from RSR at most regions but no effect on predictions of WB sweat [Na+] from REG. Results suggest that REG cannot be used as a direct surrogate for WB sweating responses. Nonetheless, the use of regression equations to predict WB sweat [Na+] from REG can provide an estimation of WB sweat [Na+] with an acceptable level of accuracy, especially using the forearm or thigh. However, the best practice for measuring WBSR remains conventional WB mass balance calculations since prediction of WBSR from RSR using absorbent patches does not meet the accuracy or reliability required to inform fluid intake recommendations. NEW & NOTEWORTHY This study developed a body map of regional sweating rate and regional (REG) sweat electrolyte concentrations and determined the effect of within-subject (bilateral and day-to-day) and between-subject (sex) factors on the relations between REG and the whole body (WB). Regression equations can be used to predict WB sweat Na+ concentration from REG, especially using the forearm or thigh. However, prediction of WB sweating rate from REG sweating rate using absorbent patches does not reach the accuracy or reliability required to inform fluid intake recommendations.

Sweat Sodium, Potassium, and Chloride Concentrations Analyzed Same Day as Collection Versus After 7 Days Storage in a Range of Temperatures.

The purpose of this study was to determine the effect of storage temperature on sodium ([Na+]), potassium ([K+]), and chloride ([Cl-]) concentrations of sweat samples analyzed 7 days after collection. Using the absorbent patch technique, 845 sweat samples were collected from 39 subjects (32 ± 7 years, 72.9 ± 10.5kg) during exercise. On the same day as collection (PRESTORAGE), 609 samples were analyzed for [Na+], [Cl-], and [K+] by ion chromatography (IC) and 236 samples were analyzed for [Na+] using a compact ion-selective electrode (ISE). Samples were stored at one of the four conditions: -20 °C (IC, n = 138; ISE, n = 60), 8 °C (IC, n = 144; ISE, n = 59), 23 °C (IC, n = 159; ISE, n = 59), or alternating between 8 °C and 23 °C (IC, n = 168; ISE, n = 58). After 7 days in storage (POSTSTORAGE), samples were reanalyzed using the same technique as PRESTORAGE. PRESTORAGE sweat electrolyte concentrations were highly related to that of POSTSTORAGE (intraclass correlation coefficient: .945-.989, p < .001). Mean differences (95% confidence intervals) between PRESTORAGE and POSTSTORAGE were statistically, but not practically, significant for most comparisons: IC [Na+]: -0.5(0.9) to -2.1(0.9) mmol/L; IC [K+]: -0.1(0.1) to -0.2(0.1) mmol/L; IC [Cl-]: -0.4(1.4) to -1.3(1.3) mmol/L; ISE [Na+]: -2.0(1.1) to 1.3(1.1) mmol/L. Based on typical error of measurement results, 95% of the time PRESTORAGE and POSTSTORAGE sweat [Na+], [K+], and [Cl-] by IC analysis fell within ±7-9, ±0.6-0.7, and ±9-13mmol/L, respectively, while sweat [Na+] by ISE was ±6 mmol/L. All conditions produced high reliability and acceptable levels of agreement in electrolyte concentrations of sweat samples analyzed on the day of collection versus after 7 days in storage.

Effect of electrolyte supplementation on electrolyte profile in Marwari horses during 20 km moderate intensity riding exercise

The effect of electrolyte supplementation on plasma electrolyte profile in horses in hot environmental conditions was studied using sweat loss and sweat electrolyte concentration. Eleven adult Marwari mares were selected for the study. To develop an electrolyte supplement, 7 mares were given a preliminary 20 km moderate intensity exercise and the electrolyte supplement was designed on basis of their body weight loss and sweat electrolyte concentration during exercise. In the subsequent trials, 4 mares were kept in an exercise control group that did not receive the supplement (ECG), while 3 mares were kept in the exercise supplementation group (ESG) that received the supplement. Four other mares were used as resting controls (RG). ESG mares were daily fed 50 g electrolyte supplement and 150 g supplement orally 1 h before the 20 km trial. Mares of ESG and ECG groups were conferred 3 km trot + canter riding every day in the morning and a 20 km trot + canter ride on every 10th day of the total trial period of 40 days. Blood analysis revealed a significant (P&lt;0.05) decline in plasma calcium and chloride concentrations immediately after exercise in both groups. There was significant less post-exercise decrease of plasma calcium and chloride concentration in ESG mares. Post-exercise plasma sodium concentration was higher (P&lt;0.05) and plasma potassium concentration was lower only in ESG mares (P&lt;0.05) compared to pre-exercise concentrations. The supplement did not affect the physiological responses (heart rate and rectal temperature). However, the changes in plasma sodium, potassium, calcium and chloride concentration were in favour of better performance in supplemented (ESG) mares and advocate sweat-developed electrolyte supplementation in riding mares.

Autonomous sweat extraction and analysis applied to cystic fibrosis and glucose monitoring using a fully integrated wearable platform

Perspiration-based wearable biosensors facilitate continuous monitoring of individuals' health states with real-time and molecular-level insight. The inherent inaccessibility of sweat in sedentary individuals in large volume (≥10 µL) for on-demand and in situ analysis has limited our ability to capitalize on this noninvasive and rich source of information. A wearable and miniaturized iontophoresis interface is an excellent solution to overcome this barrier. The iontophoresis process involves delivery of stimulating agonists to the sweat glands with the aid of an electrical current. The challenge remains in devising an iontophoresis interface that can extract sufficient amount of sweat for robust sensing, without electrode corrosion and burning/causing discomfort in subjects. Here, we overcame this challenge through realizing an electrochemically enhanced iontophoresis interface, integrated in a wearable sweat analysis platform. This interface can be programmed to induce sweat with various secretion profiles for real-time analysis, a capability which can be exploited to advance our knowledge of the sweat gland physiology and the secretion process. To demonstrate the clinical value of our platform, human subject studies were performed in the context of the cystic fibrosis diagnosis and preliminary investigation of the blood/sweat glucose correlation. With our platform, we detected the elevated sweat electrolyte content of cystic fibrosis patients compared with that of healthy control subjects. Furthermore, our results indicate that oral glucose consumption in the fasting state is followed by increased glucose levels in both sweat and blood. Our solution opens the possibility for a broad range of noninvasive diagnostic and general population health monitoring applications.

Manipulating proteostasis to repair the F508del-CFTR defect in cystic fibrosis.

Cystic fibrosis (CF) is a lethal monogenic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that entails the (diagnostic) increase in sweat electrolyte concentrations, progressive lung disease with chronic inflammation and recurrent bacterial infections, pancreatic insufficiency, and male infertility. Therapies aimed at restoring the CFTR defect have emerged. Thus, a small molecule which facilitates chloride channel opening, the potentiator Ivacaftor, has been approved for the treatment of CF patients bearing a particular class of rare CFTR mutations. However, small molecules that directly target the most common misfolded CFTR mutant, F508del, and improve its intracellular trafficking in vitro, have been less effective than expected when tested in CF patients, even in combination with Ivacaftor. Thus, new strategies are required to circumvent the F508del-CFTR defect. Airway and intestinal epithelial cells from CF patients bearing the F508del-CFTR mutation exhibit an impressive derangement of cellular proteostasis, with oxidative stress, overactivation of the tissue transglutaminase (TG2), and disabled autophagy. Proteostasis regulators such as cysteamine can rescue and stabilize a functional F508del-CFTR protein through suppressing TG2 activation and restoring autophagy in vivo in F508del-CFTR homozygous mice, in vitro in CF patient-derived cell lines, ex vivo in freshly collected primary patient’s nasal cells, as well as in a pilot clinical trial involving homozygous F508del-CFTR patients. Here, we discuss how the therapeutic normalization of defective proteostasis can be harnessed for the treatment of CF patients with the F508del-CFTR mutation.

Sweat sodium loss influences serum sodium concentration in a marathon.

The aim of this investigation was to determine the influence of sweat electrolyte concentration on body water and electrolyte homeostasis during a marathon. Fifty-one runners completed a marathon race in a warm and dry environment (24.4±3.6°C). Runners were classified as low-salt sweaters (n=21; <30mmol/L of sweat Na+ concentration), typical sweaters (n=20; ≥30 and <60mmol/L of sweat Na+ concentration), and salty sweaters (n=10; ≥60mmol/L of sweat Na+ concentration). Before and after the race, body mass and a sample of venous blood were obtained. During the race, sweat samples were collected by using sweat patches, and fluid and electrolyte intake were recorded by using self-reported questionnaires. Low-salt, typical and salty sweaters presented similar sweat rates (0.93±0.2, 0.92±0.29, 0.99±0.21L/h, respectively), body mass changes (-3.0±1.0, -3.3±1.0, -3.2±0.8%), total Na+ intake (12.7±8.1, 11.5±9.7, 14.5±16.6mmol), and fluid intake (1.3±0.8, 1.2±0.8, 1.2±0.6L) during the race. However, salty sweaters presented lower post-race serum Na+ concentration (140.8±1.3 vs 142.5±1.1, 142.4±1.4mmol/L; P<0.01) and serum osmolality (297±6 vs 299±5, 301±6mOsm/kg; P<0.05) than low-salt and typical sweaters. Sweat electrolyte concentration could influence post-race serum electrolyte concentration in the marathon. However, even the saltiest sweaters did not develop exercise-associated hyponatremia or associated symptoms.