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2.
Maturitas ; 172: 39-45, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37099982

RESUMO

OBJECTIVES: With poor sleep highly prevalent during the menopause transition, there is a need to better understand modifiable psychological resources that may be associated with improved sleep. Hence, we investigated whether self-compassion can explain variance in self-reported sleep quality in midlife women, over and above vasomotor symptoms. METHODS: This cross-sectional study (N = 274) used questionnaire data from self-report measures of sleep, hot flushes and night sweats, hot flush interference, and self-compassion, with analyses conducted using sequential (hierarchical) regression. RESULTS: Poor sleep, as measured by the Pittsburgh Sleep Quality Index, was prevalent and significantly worse in the subsample of women with hot flushes and night sweats, g = 0.28, 95 % CI [0.04, 0.53]. The interference of hot flushes in everyday life (ß = 0.35, p < .01), but not their frequency, predicted self-reported sleep quality. Once self-compassion was added to the model it was the only predictor of poor sleep (ß = -0.32, p < .01). When positive self-compassion and self-coldness were considered separately, the effect on sleep quality appeared to be attributable to self-coldness scores alone (ß = 0.29, p < .05). CONCLUSIONS: Self-compassion may have a stronger relationship with self-reported sleep quality in midlife women than vasomotor symptoms. Future intervention-based research could test the efficacy of self-compassion training for midlife women experiencing sleep disturbances, as this may be an important and modifiable psychological resilience factor.


Assuntos
Autocompaixão , Qualidade do Sono , Feminino , Humanos , Estudos Transversais , Sudorese , Fogachos/complicações , Fogachos/psicologia , Menopausa/psicologia
3.
J Appl Physiol (1985) ; 134(5): 1300-1311, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37022963

RESUMO

The purpose of this study was to characterize thermoregulatory and performance responses of elite road-race athletes, while competing in hot, humid, night-time conditions during the 2019 IAAF World Athletic Championships. Male and female athletes, competing in the 20 km racewalk (n = 20 males, 24 females), 50 km racewalk (n = 19 males, 8 females), and marathon (n = 15 males, 22 females) participated. Exposed mean skin (Tsk) and continuous core body (Tc) temperature were recorded with infrared thermography and ingestible telemetry pill, respectively. The range of ambient conditions (recorded roadside) was 29.3°C-32.7°C air temperature, 46%-81% relative humidity, 0.1-1.7 m·s-1 air velocity, and 23.5°C-30.6°C wet bulb globe temperature. Tc increased by 1.5 ± 0.1°C but mean Tsk decreased by 1.5 ± 0.4°C over the duration of the races. Tsk and Tc changed most rapidly at the start of the races and then plateaued, with Tc showing a rapid increase again at the end, in a pattern mirroring pacing. Performance times were between 3% and 20% (mean = 113 ± 6%) longer during the championships compared with the personal best (PB) of athletes. Overall mean performance relative to PB was correlated with the wet-bulb globe temperature (WBGT) of each race (R2 = 0.89), but not with thermophysiological variables (R2 ≤ 0.3). As previously reported in exercise heat stress, in this field study Tc rose with exercise duration, whereas Tsk showed a decline. The latter contradicts the commonly recorded rise and plateau in laboratory studies at similar ambient temperatures but without realistic air movement.NEW & NOTEWORTHY This paper provides a kinetic observation of both core and skin temperatures in 108 elite athletes, during various outdoor competition events, adding to the very limited data so far available in the literature taken during elite competitions. The field skin temperature findings contrast previous laboratory findings, likely due to differences in relative air velocity and its impact on the evaporation of sweat. The rapid rise in skin temperature following cessation of exercise highlights the importance of infrared thermography measurements being taken during motion, not during breaks, when being used as a measurement of skin temperature during exercise.


Assuntos
Regulação da Temperatura Corporal , Esportes , Humanos , Masculino , Feminino , Regulação da Temperatura Corporal/fisiologia , Sudorese , Temperatura Cutânea , Exercício Físico/fisiologia , Temperatura Alta
4.
J Appl Physiol (1985) ; 134(6): 1364-1375, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37055036

RESUMO

Renal ischemia-reperfusion (I/R) injury results in damage to the renal tubules and causes impairments in sodium [Na+] reabsorption. Given the inability to conduct mechanistic renal I/R injury studies in vivo in humans, eccrine sweat glands have been proposed as a surrogate model given the anatomical and physiological similarities. We tested the hypothesis that sweat Na+ concentration is elevated following I/R injury during passive heat stress. We also tested the hypothesis that I/R injury during heat stress will impair cutaneous microvascular function. Fifteen young healthy adults completed ∼160 min of passive heat stress using a water-perfused suit (50°C). At 60 min of whole body heating, one upper arm was occluded for 20 min followed by a 20-min reperfusion. Sweat was collected from each forearm via an absorbent patch pre- and post-I/R. Following the 20-min reperfusion, cutaneous microvascular function was measured via local heating protocol. Cutaneous vascular conductance (CVC) was calculated as red blood cell flux/mean arterial pressure and normalized to CVC during local heating to 44°C. Na+ concentration was log-transformed and data were reported as a mean change from pre-I/R (95% confidence interval). Changes in sweat sodium concentration from pre-I/R differed between arms post-I/R (experimental arm: +0.97 [+0.67 - 1.27] [LOG] Na+; control arm: +0.68 [+0.38 - 0.99] [LOG] Na+; P < 0.01). However, CVC during the local heating was not different between the experimental (80 ± 10%max) and control arms (78 ± 10%max; P = 0.59). In support of our hypothesis, Na+ concentration was elevated following I/R injury, but likely not accompanied by alterations in cutaneous microvascular function.NEW & NOTEWORTHY In the present study, we have demonstrated that sweat sodium concentration is elevated following ischemia-reperfusion injury during passive heat stress. This does not appear to be mediated by reductions in cutaneous microvascular function or active sweat glands, but may be related to alterations in local sweating responses during heat stress. This study demonstrates a potential use of eccrine sweat glands to understand sodium handling following ischemia-reperfusion injury, particularly given the challenges of in vivo studies of renal ischemia-reperfusion injury in humans.


Assuntos
Traumatismo por Reperfusão , Pele , Adulto , Humanos , Pele/irrigação sanguínea , Suor/fisiologia , Vasodilatação/fisiologia , Sudorese , Resposta ao Choque Térmico/fisiologia , Sódio , Temperatura Alta
5.
J Appl Physiol (1985) ; 134(6): 1376-1389, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37055034

RESUMO

We tested the hypothesis that women may be more at risk of becoming dehydrated during physical work in the heat in the early follicular phase (EF), compared with the late follicular (LF) and mid-luteal (ML) phases of the menstrual cycle when allowed free access to drink. Twelve healthy, eumenorrheic, unacclimated women (26 ± 5 yr) completed three trials (EF, LF, and ML phases) involving 4 h of exposure to 33.8 ± 0.8 °C, 54 ± 1% relative humidity. Each hour, participants walked on a treadmill for 30 min at a rate of metabolic heat production of 338 ± 9 W. Participants drank a cool, flavor-preferred non-caloric sport drink ad libitum. Nude body weight was measured pre- and post-exposure, and percent changes in body weight loss were interpreted as an index of changes in total body water. Total fluid intake and urine output were measured and sweat rate was estimated from changes in body mass corrected for fluid intake and urine output. Fluid intake was not different between phases (EF: 1,609 ± 919 mL; LF: 1,902 ± 799 mL; ML: 1,913 ± 671; P = 0.202). Total urine output (P = 0.543) nor sweat rate (P = 0.907) differed between phases. Percent changes in body mass were not different between phases (EF: -0.5 ± 0.9%; LF: -0.3 ± 0.9%; ML: -0.3 ± 0.7%; P = 0.417). This study demonstrates that the normal hormonal fluctuations that occur throughout the menstrual cycle do not alter fluid balance during physical work in the heat.NEW & NOTEWORTHY The effect of the menstrual cycle on fluid balance during physical work in the heat when fluids are freely available is unknown. This study demonstrates that fluid balance is not modified in women across three distinct phases of the menstrual cycle during physical work in the heat These results indicate that when women have free access to cool fluid during physical work in the heat, they respond similarly across all three phases to maintain fluid homeostasis across the menstrual cycle.


Assuntos
Temperatura Alta , Ciclo Menstrual , Feminino , Humanos , Sudorese , Caminhada , Equilíbrio Hidroeletrolítico
6.
Int J Mol Sci ; 24(8)2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37108325

RESUMO

X-linked hypohidrotic ectodermal dysplasia (XLHED), caused by a genetic deficiency of ectodysplasin A1 (EDA1), is a rare developmental disorder of ectodermal derivatives such as hair, sweat glands, and teeth. The absence of sweat glands and perspiration can evoke life-threatening hyperthermia. As molecular genetic findings are not always conclusive, the concentrations of circulating EDA1 may help to distinguish between total and partial EDA1 deficiencies. We previously treated nine male patients with obvious signs of XLHED with a recombinant EDA1 replacement protein, Fc-EDA, either shortly after birth (n = 3) or by prenatal administration in gestational week 26 and beyond (n = 6). Here, we present the long-term follow-up for up to six years. In patients who had received Fc-EDA after birth, neither sweat glands nor sweating ability were detected at the age of 12-60 months. In contrast, prenatal EDA1 replacement resulted in ample sweat gland development and pilocarpine-inducible sweating in all treated subjects, who also attained more permanent teeth than their untreated affected relatives. Normal perspiration has persisted for six years in the two oldest boys treated repeatedly with Fc-EDA in utero. When they had a sauna, adequate thermoregulation was evidenced. Lower sweat production after single prenatal dosing may indicate a dose-response relationship. The absence of circulating EDA1 in five prenatally treated subjects proved that these children would have been unable to perspire if they had been left untreated. The sixth infant was shown to produce an EDA1 molecule that, albeit interacting with its cognate receptor, cannot activate EDA1 signaling. In conclusion, a causal treatment of XLHED before birth is feasible.


Assuntos
Displasia Ectodérmica Anidrótica Tipo 1 , Displasia Ectodérmica , Criança , Gravidez , Feminino , Lactente , Humanos , Masculino , Pré-Escolar , Displasia Ectodérmica Anidrótica Tipo 1/genética , Displasia Ectodérmica Anidrótica Tipo 1/terapia , Ectodisplasinas/genética , Displasia Ectodérmica/genética , Sudorese , Cabelo , Proteínas Recombinantes
7.
Lab Chip ; 23(9): 2268-2275, 2023 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-37043225

RESUMO

Research targeting the development of on-body sensors has been significantly growing in recent years - an example is on-skin sweat sensing. However, the wide inter and intra person variability of skin characteristics make in vivo testing of these sensors and included materials such as skin adhesives difficult, which hampers especially the initial development phase of such wearables. Besides the development of wearable sweat sensors, companies developing deodorants, cosmetics, medical adhesives and wearable textiles now need to perform expensive human subjects testing with little control over the exact sweat mechanisms. Hence, there is a need for a realistic, adaptable and stable test platform, or artificial skin. We present a versatile artificial skin platform that faithfully recapitulates skin topography, active sweat pores, skin wetting behaviour and sweat rate, and that can be tuned to mimic the specifications of the targeted body location and sweating characteristics. The developed artificial skin is capable of generating sweat rates as low as 0.1 nL min-1 pore-1 and as high as 100 nL min-1 pore-1, spanning the whole range of physiological sweat rates. Specifically, the platform can be used for the development of sweat sensors for sedentary persons whose sweat rates are commonly lower than currently delivered by any other artificial skin platform.


Assuntos
Técnicas Biossensoriais , Pele Artificial , Humanos , Sudorese , Suor , Pele
8.
Nutrients ; 15(7)2023 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-37049589

RESUMO

Elite squash players are reported to train indoors at high volumes and intensities throughout a microcycle. This may increase hydration demands, with hypohydration potentially impairing many key performance indicators which characterise elite squash performance. Consequently, the main aim of this study was to quantify the sweat rates and sweat [Na+] of elite squash players throughout a training session, alongside their hydration practices. Fourteen (males = seven; females = seven) elite or world class squash player's fluid balance, sweat [Na+] and hydration practices were calculated throughout a training session in moderate environmental conditions (20 ± 0.4 °C; 40.6 ± 1% RH). Rehydration practices were also quantified post-session until the players' next training session, with some training the same day and some training the following day. Players had a mean fluid balance of -1.22 ± 1.22% throughout the session. Players had a mean sweat rate of 1.11 ± 0.56 L·h-1, with there being a significant difference between male and female players (p < 0.05), and a mean sweat (Na+) of 46 ± 12 mmol·L-1. Players training the following day were able to replace fluid and sodium losses, whereas players training again on the same day were not. These data suggest the variability in players hydration demands and highlight the need to individualise hydration strategies, as well as training prescription, to ensure players with high hydration demands have ample time to optimally rehydrate.


Assuntos
Sódio , Equilíbrio Hidroeletrolítico , Masculino , Humanos , Feminino , Sudorese , Suor , Hidratação , Desidratação/prevenção & controle , Ingestão de Líquidos
9.
Sensors (Basel) ; 23(7)2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37050438

RESUMO

The relationship between the onset of sweating (OS) and sweat lactate threshold (sLT) assessed using a novel sweat lactate sensor remains unclear. We aimed to investigate the implications of the OS on the sLT. Forty healthy men performed an incremental cycling test. We monitored the sweat lactate, blood lactate, and local sweating rates to determine the sLT, blood LT (bLT), and OS. We defined participants with the OS during the warm-up just before the incremental test as the early perspiration (EP) group and the others as the regular perspiration (RP) group. Pearson's correlation coefficient analysis revealed that the OS was poorly correlated with the sLT, particularly in the EP group (EP group, r = 0.12; RP group, r = 0.56). Conversely, even in the EP group, the sLT was strongly correlated with the bLT (r = 0.74); this was also the case in the RP group (r = 0.61). Bland-Altman plots showed no bias between the mean sLT and bLT (mean difference: 19.3 s). Finally, in five cases with a later OS than bLT, the sLT tended to deviate from the bLT (mean difference, 106.8 s). The sLT is a noninvasive and continuous alternative to the bLT, independent of an early OS, although a late OS may negatively affect the sLT.


Assuntos
Suor , Sudorese , Masculino , Humanos , Ácido Láctico , Ciclismo
10.
J Therm Biol ; 113: 103477, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37055108

RESUMO

INTRODUCTION: this study describes the development of a female finite element thermoregulatory model (FETM) METHOD: the female body model was developed from medical image datasets of a median U.S. female and was constructed to be anatomically correct. The body model preserves the geometric shapes of 13 organs and tissues, including skin, muscles, fat, bones, heart, lungs, brain, bladder, intestines, stomach, kidneys, liver, and eyes. Heat balance within the body is described by the bio-heat transfer equation. Heat exchange at the skin surface includes conduction, convection, radiation, and sweat evaporation. Vasodilation, vasoconstriction, sweating, and shivering are controlled by afferent and efferent signals to and from the skin and hypothalamus. RESULTS: the model was validated with measured physiological data during exercise and rest in thermoneutral, hot, and cold conditions. Validations show the model predicted the core temperature (rectal and tympanic temperatures) and mean skin temperatures with acceptable accuracy (within 0.5 °C and 1.6 °C, respectively) CONCLUSION: this female FETM predicted high spatial resolution temperature distribution across the female body, which provides quantitative insights into human thermoregulatory responses in females to non-uniform and transient environmental exposure.


Assuntos
Regulação da Temperatura Corporal , Sudorese , Feminino , Humanos , Análise de Elementos Finitos , Regulação da Temperatura Corporal/fisiologia , Temperatura Corporal/fisiologia , Temperatura Cutânea , Febre , Temperatura Alta
11.
J Therm Biol ; 113: 103507, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37055125

RESUMO

The purpose of this study was to determine whether young children's thermoregulation during heat exposure varies with age and body size. A total of 34 young children (aged 6 months-8 years)-18 boys and 16 girls-participated in the study. They were divided into five groups according to age (<1 year, 1 year, 2-3 years, 4-5 years, and 8 years). The participants sat for 30 min in a 27°C, 50% rh room, then moved to a 35°C, 70% rh room and remained seated for at least 30 min. They then returned to the first 27°C room and remained stationary for 30 min. Rectal temperature (Tre) and skin temperature (Tsk) were continuously recorded, and the amount of whole-body sweat rate (SR) was measured. Local SR of the back and upper arm were collected with filter paper to calculate local sweating volume, and Na + concentration was measured later. The smaller the age, the significantly greater the increase in Tre. There was no significant difference in the amount of whole-body SR and the increase in Tsk during the heating among the five groups. Furthermore, there was no significant difference in whole-body SR per increase in Tre during heating between the five groups, but a significant difference was found in back local SR per increase in Tre with age. Difference in local SR between upper arm and back was observed at age 2 years and above, and difference in Na+ concentrations in sweat was observed at age 8 years. The development of thermoregulatory responses with growth was observed. The results indicate that the thermoregulatory response is disadvantaged by immature mechanisms and small body size in younger children.


Assuntos
Temperatura Corporal , Temperatura Alta , Masculino , Feminino , Humanos , Criança , Pré-Escolar , Regulação da Temperatura Corporal/fisiologia , Sudorese , Temperatura Cutânea , Sódio
12.
J Therm Biol ; 113: 103535, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37055138

RESUMO

PURPOSE: Determine if topical capsaicin, a transient receptor potential vanilloid heat thermoreceptor activator, alters thermoregulation and perception when applied topically prior to thermal exercise. METHODS: Twelve subjects completed 2 treatments. Subjects walked (1.6 m s-1, 5% grade) for 30 min in the heat (38 °C, 60% relative humidity) with either a capsaicin (0.025% capsaicin) or control cream applied to the upper (shoulder to wrist) and lower (mid-thigh to ankle) limbs covering ∼50% body surface area. Skin blood flow (SkBF), sweat (rate, composition), heart rate, temperature (skin, core), and perceived thermal sensation were measured prior to and during exercise. RESULTS: The relative change in SkBF was not different between treatments at any time point (p = 0.284). There were no differences in sweat rate between the capsaicin (1.23 ± 0.37 L h-1) and control (1.43 ± 0.43 L h-1, p = 0.122). There were no differences in heart rate between the capsaicin (122 ± 38 beats·min-1) and control (125 ± 39 beats·min-1, p = 0.431). There were also no differences in weighted surface (p = 0.976) or body temperatures (p = 0.855) between the capsaicin (36.0 ± 1.7 °C, 37.0 ± 0.8 °C, respectively) and control (36.0 ± 1.6 °C, 36.9 ± 0.8 °C, respectively). The capsaicin treatment was not perceived as hotter than the control treatment until minute 30 of exercise (2.8 ± 0.4, 2.5 ± 0.5, respectively, p = 0.038) CONCLUSIONS: Topical capsaicin application does not alter whole-body thermoregulation during acute exercise in the heat despite perceiving the treatment as hotter late in exercise.


Assuntos
Capsaicina , Temperatura Alta , Humanos , Capsaicina/farmacologia , Temperatura Cutânea , Regulação da Temperatura Corporal/fisiologia , Sudorese , Temperatura Corporal/fisiologia , Exercício Físico/fisiologia , Percepção
13.
Maturitas ; 171: 13-20, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36907116

RESUMO

INTRODUCTION: Vasomotor symptoms (VMS) are the symptoms most frequently experienced by women transitioning to menopause and are a primary indication for menopausal hormone therapy. A growing body of evidence has associated the presence of VMS with future risk for cardiovascular disease (CVD) events. This study aimed to systematically evaluate, qualitatively and quantitatively, the possible association between VMS and the risk for incident CVD. METHODS: This systematic review and meta-analysis included 11 studies evaluating peri- and postmenopausal women in a prospective design. The association between VMS (hot flashes and/or night sweats) and the incidence of major adverse cardiovascular events, including coronary heart disease (CHD) and stroke, was explored. Associations are expressed as relative risks (RR) with 95 % confidence intervals (CI). RESULTS: The risk for incident CVD events in women with and without VMS differed according to the age of participants. Women with VSM younger than 60 years at baseline had a higher risk of an incident CVD event than women without VSM of the same age (RR 1.12, 95 % CI 1.05-1.19, I2 0%). Conversely, the incidence of CVD events was not different between women with and without VMS in the age group >60 years (RR 0.96, 95 % CI 0.92-1.01, I2 55%). CONCLUSION: The association between VMS and incident CVD events differs with age. VMS increases the incidence of CVD only in women under 60 years of age at baseline. The findings of this study are limited by the high heterogeneity among studies, pertaining mainly to different population characteristics, definitions of menopausal symptoms and recall bias.


Assuntos
Doenças Cardiovasculares , Feminino , Humanos , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/complicações , Pós-Menopausa , Fatores de Risco , Menopausa , Fogachos/complicações , Fogachos/epidemiologia , Sistema Vasomotor , Sudorese
14.
Sensors (Basel) ; 23(5)2023 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-36904697

RESUMO

The ion-sensitive field-effect transistor is a well-established electronic device typically used for pH sensing. The usability of the device for detecting other biomarkers in easily accessible biologic fluids, with dynamic range and resolution compliant with high-impact medical applications, is still an open research topic. Here, we report on an ion-sensitive field-effect transistor that is able to detect the presence of chloride ions in sweat with a limit-of-detection of 0.004 mol/m3. The device is intended for supporting the diagnosis of cystic fibrosis, and it has been designed considering two adjacent domains, namely the semiconductor and the electrolyte containing the ions of interest, by using the finite element method, which models the experimental reality with great accuracy. According to the literature explaining the chemical reactions that take place between the gate oxide and the electrolytic solution, we have concluded that anions directly interact with the hydroxyl surface groups and replace protons previously adsorbed from the surface. The achieved results confirm that such a device can be used to replace the traditional sweat test in the diagnosis and management of cystic fibrosis. In fact, the reported technology is easy-to-use, cost-effective, and non-invasive, leading to earlier and more accurate diagnoses.


Assuntos
Técnicas Biossensoriais , Fibrose Cística , Humanos , Cloretos/química , Sudorese , Potenciometria
15.
Int J Mol Sci ; 24(5)2023 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-36902003

RESUMO

Sweat plays a critical role in human body, including thermoregulation and the maintenance of the skin environment and health. Hyperhidrosis and anhidrosis are caused by abnormalities in sweat secretion, resulting in severe skin conditions (pruritus and erythema). Bioactive peptide and pituitary adenylate cyclase-activating polypeptide (PACAP) was isolated and identified to activate adenylate cyclase in pituitary cells. Recently, it was reported that PACAP increases sweat secretion via PAC1R in mice and promotes the translocation of AQP5 to the cell membrane through increasing intracellular [Ca2+] via PAC1R in NCL-SG3 cells. However, intracellular signaling mechanisms by PACAP are poorly clarified. Here, we used PAC1R knockout (KO) mice and wild-type (WT) mice to observe changes in AQP5 localization and gene expression in sweat glands by PACAP treatment. Immunohistochemistry revealed that PACAP promoted the translocation of AQP5 to the lumen side in the eccrine gland via PAC1R. Furthermore, PACAP up-regulated the expression of genes (Ptgs2, Kcnn2, Cacna1s) involved in sweat secretion in WT mice. Moreover, PACAP treatment was found to down-regulate the Chrna1 gene expression in PAC1R KO mice. These genes were found to be involved in multiple pathways related to sweating. Our data provide a solid basis for future research initiatives in order to develop new therapies to treat sweating disorders.


Assuntos
Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Suor , Camundongos , Humanos , Animais , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Suor/metabolismo , Sudorese , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Hipófise/metabolismo
16.
J Therm Biol ; 112: 103457, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36796903

RESUMO

Thermal discomfort due to accumulated sweat increasing head skin wettedness may contribute to low wearing rates of bicycle helmets. Using curated data on human head sweating and helmet thermal properties, a modelling framework for the thermal comfort assessment of bicycle helmet use is proposed. Local sweat rates (LSR) at the head were predicted as the ratio to the gross sweat rate (GSR) of the whole body or by sudomotor sensitivity (SUD), the change in LSR per change in body core temperature (Δtre). Combining those local models with Δtre and GSR output from thermoregulation models, we simulated head sweating depending on the characteristics of the thermal environment, clothing, activity, and exposure duration. Local thermal comfort thresholds for head skin wettedness were derived in relation to thermal properties of bicycle helmets. The modelling framework was supplemented by regression equations predicting the wind-related reductions in thermal insulation and evaporative resistance of the headgear and boundary air layer, respectively. Comparing the predictions of local models coupled with different thermoregulation models to LSR measured at the frontal, lateral and medial head under bicycle helmet use revealed a large spread in LSR predictions predominantly determined by the local models and the considered head region. SUD tended to overestimate frontal LSR but performed better for lateral and medial head regions, whereas predictions by LSR/GSR ratios were lower and agreed better with measured frontal LSR. However, even for the best models root mean squared prediction errors exceeded experimental SD by 18-30%. From the high correlation (R > 0.9) of skin wettedness comfort thresholds with local sweating sensitivity reported for different body regions, we derived a threshold value of 0.37 for head skin wettedness. We illustrate the application of the modelling framework using a commuter-cycling scenario, and discuss its potential as well as the needs for further research.


Assuntos
Ciclismo , Dispositivos de Proteção da Cabeça , Humanos , Sudorese , Regulação da Temperatura Corporal/fisiologia , Pele
17.
J Therm Biol ; 112: 103487, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36796928

RESUMO

This study aimed to explore the effects of a liquid cooling garment on the physiological and psychological strains of firefighters. Twelve participants wearing firefighting protective equipment with the liquid cooling garment (LCG group) and without the liquid cooling garment (CON group) were recruited to conduct human trials in a climate chamber. During the trials, physiological parameters (mean skin temperature (Tsk), core temperature (Tc), and heart rate (HR)) and psychological parameters (thermal sensation vote (TSV), thermal comfort vote (TCV), and rating of perceived exertion (RPE)) were measured continuously. The heat storage, sweating loss, physiological strain index (PSI), and perceptual strain index (PeSI) were calculated. The results indicated that the liquid cooling garment decreased the mean skin temperature (maximum value of 0.62 °C), scapula skin temperature (maximum value of 1.90 °C), sweating loss (26%), and PSI (0.95 scales) with a significant difference (p < 0.05) at some time points when compared with the CON group. Moreover, the liquid cooling garment had little influence (p > 0.05) on core temperature, heart rate, TSV, TCV, RPE, and PeSI. The association analysis indicated that psychological strain had the potential to predict physiological heat strain with an R2 value of 0.86 between the PeSI and PSI. This study offers insights into the evaluation of cooling system performance, the design of next-generation cooling systems, and the improvement of firefighters' benefits.


Assuntos
Bombeiros , Humanos , Roupa de Proteção , Temperatura Cutânea , Sudorese , Clima , Frequência Cardíaca/fisiologia , Temperatura Alta , Regulação da Temperatura Corporal/fisiologia , Temperatura Corporal/fisiologia
18.
JAMA ; 329(5): 405-420, 2023 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-36749328

RESUMO

Importance: Menopause, due to loss of ovarian follicular activity without another pathological or physiological cause, typically occurs between the ages of 45 years and 56 years. During the menopausal transition, approximately 50% to 75% of women have hot flashes, night sweats, or both (vasomotor symptoms) and more than 50% have genitourinary symptoms (genitourinary syndrome of menopause [GSM]). Observations: Vasomotor symptoms typically last more than 7 years and GSM is often chronic. Efficacious treatments for women with bothersome vasomotor symptoms or GSM symptoms include hormonal and nonhormonal options. Systemic estrogen alone or combined with a progestogen reduces the frequency of vasomotor symptoms by approximately 75%. Oral and transdermal estrogen have similar efficacy. Conjugated equine estrogens (CEE) with or without medroxyprogesterone acetate (MPA) were the only hormonal treatments for which clinical trials were designed to examine cardiovascular events, venous thromboembolism, and breast cancer risk. Compared with placebo, the increased risk of stroke and venous thromboembolism associated with CEE (with or without MPA) and breast cancer (with use of CEE plus MPA) is approximately 1 excess event/1000 person-years. Low-dose CEE plus bazedoxifene is not associated with increased risk of breast cancer (0.25%/year vs 0.23%/year with placebo). Bioidentical estrogens approved by the US Food and Drug Administration (with identical chemical structure to naturally produced estrogens, and often administered transdermally) also are available to treat vasomotor symptoms. For women who are not candidates for hormonal treatments, nonhormonal approaches such as citalopram, desvenlafaxine, escitalopram, gabapentin, paroxetine, and venlafaxine are available and are associated with a reduction in frequency of vasomotor symptoms by approximately 40% to 65%. Low-dose vaginal estrogen is associated with subjective improvement in GSM symptom severity by approximately 60% to 80%, with improvement in severity by 40% to 80% for vaginal prasterone, and with improvement in severity by 30% to 50% for oral ospemifene. Conclusions and Relevance: During the menopausal transition, approximately 50% to 75% of women have vasomotor symptoms and GSM symptoms. Hormonal therapy with estrogen is the first-line therapy for bothersome vasomotor symptoms and GSM symptoms, but nonhormonal medications (such as paroxetine and venlafaxine) also can be effective. Hormone therapy is not indicated for the prevention of cardiovascular disease.


Assuntos
Doenças do Sistema Nervoso Autônomo , Terapia de Reposição de Estrogênios , Doenças Urogenitais Femininas , Menopausa , Feminino , Humanos , Terapia de Reposição de Estrogênios/métodos , Estrogênios/uso terapêutico , Estrogênios Conjugados (USP)/efeitos adversos , Fogachos/tratamento farmacológico , Fogachos/etiologia , Acetato de Medroxiprogesterona/uso terapêutico , Menopausa/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Paroxetina/farmacologia , Cloridrato de Venlafaxina/farmacologia , Cloridrato de Venlafaxina/uso terapêutico , Tromboembolia Venosa/tratamento farmacológico , Tromboembolia Venosa/etiologia , Sudorese , Doenças Urogenitais Femininas/etiologia , Doenças do Sistema Nervoso Autônomo/etiologia
19.
Physiol Behav ; 263: 114126, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36787810

RESUMO

Temperature sensitive receptors in the skin and deep body enable the detection of the external and internal environment, including the perception of thermal stimuli. Changes in heat balance require autonomic (e.g., sweating) and behavioral (e.g., seeking shade) thermoeffector initiation to maintain thermal homeostasis. Sex differences in body morphology can largely, but not entirely, account for divergent responses in thermoeffector and perceptual responses to environmental stress between men and women. Thus, it has been suggested that innate differences in thermosensation may exist between men and women. Our goal in this review is to summarize the existing literature that investigates localized and whole-body cold and heat exposure pertaining to sex differences in thermal sensitivity and perception, and the interplay between autonomic and behavioral thermoeffector responses. Overall, it appears that local differences in thermal sensitivity and perception are minimized, yet still apparent, when morphological characteristics are well-controlled. Sex differences in the early vasomotor response to environmental stress and subsequent changes in blood flow likely contribute to the heightened thermal awareness observed in women. However, the contribution of thermoreceptors to observed sex differences in thermal perception and thermoeffector function is unclear, as human studies investigating these questions have not been performed.


Assuntos
Regulação da Temperatura Corporal , Caracteres Sexuais , Feminino , Humanos , Masculino , Regulação da Temperatura Corporal/fisiologia , Sudorese , Pele/irrigação sanguínea , Temperatura Cutânea , Percepção/fisiologia
20.
J Therm Biol ; 112: 103418, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36796883

RESUMO

The structure of the coat and integument of small ruminants reared in semi-arid regions have valuable characteristics that favor their adaptation to the region. The objective of this study was to evaluate the structural characteristics of the coat and integument and sweating capacity of goats and sheep in the Brazilian semi-arid region, using 20 animals, 10 of each breed, 5 males and 5 females of each species, grouped in a completely randomized design in a 2 x 2 factorial scheme (2 species and 2 genders) with 5 replicates. The animals were already being kept under the influence of high temperatures and levels of direct solar radiation before the day of the collections. At the time of the evaluations, ambient temperature was high, with low relative humidity. The pattern of epidermal thickness and sweat glands per body region was superior in sheep (P < 0.05), and the number of hair follicles and sweat rate were similar (P > 0.05) between the species. There was no difference (P > 0.05) in the evaluated characteristics between the genders, showing that they are not influenced by hormones. The morphology of the coat and skin of these animals showed a superiority of goats compared to sheep.


Assuntos
Pele , Glândulas Sudoríparas , Animais , Feminino , Masculino , Brasil , Cabras , Ovinos , Pele/anatomia & histologia , Sudorese
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