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1.
Physiol Rep ; 12(11): e16107, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38849294

RESUMO

July 2023 has been confirmed as Earth's hottest month on record, and it was characterized by extraordinary heatwaves across southern Europe. Field data collected under real heatwave periods could add important evidence to understand human adaptability to extreme heat. However, field studies on human physiological responses to heatwave periods remain limited. We performed field thermo-physiological measurements in a healthy 37-years male undergoing resting and physical activity in an outdoor environment in the capital of Sicily, Palermo, during (July 21; highest level of local heat-health alert) and following (August 10; lowest level of local heat-health alert) the peak of Sicily's July 2023 heatwave. Results indicated that ~40 min of outdoor walking and light running in 33.8°C Wet Bulb Globe Temperature (WBGT) conditions (July 21) resulted in significant physiological stress (i.e., peak heart rate: 209 bpm; core temperature: 39.13°C; mean skin temperature: 37.2°C; whole-body sweat losses: 1.7 kg). Importantly, significant physiological stress was also observed during less severe heat conditions (August 10; WBGT: 29.1°C; peak heart rate: 190 bpm; core temperature: 38.48°C; whole-body sweat losses: 2 kg). These observations highlight the physiological strain that current heatwave conditions pose on healthy young individuals. This ecologically-valid empirical evidence could inform more accurate heat-health planning.


Assuntos
Calor Extremo , Frequência Cardíaca , Humanos , Masculino , Adulto , Sicília , Frequência Cardíaca/fisiologia , Calor Extremo/efeitos adversos , Sudorese/fisiologia , Temperatura Corporal/fisiologia , Regulação da Temperatura Corporal/fisiologia , Temperatura Cutânea/fisiologia , Temperatura Alta/efeitos adversos
2.
Nutrients ; 16(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38732589

RESUMO

Sweat rate and electrolyte losses have a large inter-individual variability. A personalized approach to hydration can overcome this issue to meet an individual's needs. This study aimed to investigate the effects of a personalized hydration strategy (PHS) on fluid balance and intermittent exercise performance. Twelve participants conducted 11 laboratory visits including a VO2max test and two 5-day trial arms under normothermic (NOR) or hyperthermic (HYP) environmental conditions. Each arm began with three days of familiarization exercise followed by two random exercise trials with either a PHS or a control (CON). Then, participants crossed over to the second arm for: NOR+PHS, NOR+CON, HYP+PHS, or HYP+CON. The PHS was prescribed according to the participants' fluid and sweat sodium losses. CON drank ad libitum of commercially-available electrolyte solution. Exercise trials consisted of two phases: (1) 45 min constant workload; (2) high-intensity intermittent exercise (HIIT) until exhaustion. Fluids were only provided in phase 1. PHS had a significantly greater fluid intake (HYP+PHS: 831.7 ± 166.4 g; NOR+PHS: 734.2 ± 144.9 g) compared to CON (HYP+CON: 369.8 ± 221.7 g; NOR+CON: 272.3 ± 143.0 g), regardless of environmental conditions (p < 0.001). HYP+CON produced the lowest sweat sodium concentration (56.2 ± 9.0 mmol/L) compared to other trials (p < 0.001). HYP+PHS had a slower elevated thirst perception and a longer HIIT (765 ± 452 s) compared to HYP+CON (548 ± 283 s, p = 0.04). Thus, PHS reinforces fluid intake and successfully optimizes hydration status, regardless of environmental conditions. PHS may be or is an important factor in preventing negative physiological consequences during high-intensity exercise in the heat.


Assuntos
Exercício Físico , Temperatura Alta , Equilíbrio Hidroeletrolítico , Humanos , Equilíbrio Hidroeletrolítico/fisiologia , Masculino , Exercício Físico/fisiologia , Adulto , Adulto Jovem , Feminino , Sudorese/fisiologia , Desidratação/prevenção & controle , Desidratação/terapia , Ingestão de Líquidos/fisiologia , Suor/química , Estudos Cross-Over
3.
J Appl Physiol (1985) ; 136(6): 1478-1487, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38695357

RESUMO

Our aim was to develop and validate separate whole body sweat rate prediction equations for moderate to high-intensity outdoor cycling and running, using simple measured or estimated activity and environmental inputs. Across two collection sites in Australia, 182 outdoor running trials and 158 outdoor cycling trials were completed at a wet-bulb globe temperature ranging from ∼15°C to ∼29°C, with ∼60-min whole body sweat rates measured in each trial. Data were randomly separated into model development (running: 120; cycling: 100 trials) and validation groups (running: 62; cycling: 58 trials), enabling proprietary prediction models to be developed and then validated. Running and cycling models were also developed and tested when locally measured environmental conditions were substituted with participants' subjective ratings for black globe temperature, wind speed, and humidity. The mean absolute error for predicted sweating rate was 0.03 and 0.02 L·h-1 for running and cycling models, respectively. The 95% confidence intervals for running (+0.44 and -0.38 L·h-1) and cycling (+0.45 and -0.42 L·h-1) were within acceptable limits for an equivalent change in total body mass over 3 h of ±2%. The individual variance in observed sweating described by the predictive models was 77% and 60% for running and cycling, respectively. Substituting measured environmental variables with subjective assessments of climatic characteristics reduced the variation in observed sweating described by the running model by up to ∼25%, but only by ∼2% for the cycling model. These prediction models are publicly accessible (https://sweatratecalculator.com) and can guide individualized hydration management in advance of outdoor running and cycling.NEW & NOTEWORTHY We report the development and validation of new proprietary whole body sweat rate prediction models for outdoor running and outdoor cycling using simple activity and environmental inputs. Separate sweat rate models were also developed and tested for situations where all four environmental parameters are not available, and some must be subsequently estimated by the user via a simple rating scale. All models are freely accessible through an online calculator: https://sweatratecalculator.com. These models, via the online calculator, will enable individualized hydration management for training or recreational cycling or running in an outdoor environment.


Assuntos
Ciclismo , Corrida , Sudorese , Humanos , Corrida/fisiologia , Sudorese/fisiologia , Masculino , Ciclismo/fisiologia , Adulto , Feminino , Exercício Físico/fisiologia , Adulto Jovem , Temperatura , Modelos Biológicos , Austrália
4.
Int J Mol Sci ; 25(9)2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38731882

RESUMO

In cholinergic urticaria (CholU), small, itchy wheals are induced by exercise or passive warming and reduced sweating has been reported. Despite the described reduced muscarinic receptor expression, sweat duct obstruction, or sweat allergy, the underlying pathomechanisms are not well understood. To gain further insights, we collected skin biopsies before and after pulse-controlled ergometry and sweat after sauna provocation from CholU patients as well as healthy controls. CholU patients displayed partially severely reduced local sweating, yet total sweat volume was unaltered. However, sweat electrolyte composition was altered, with increased K+ concentration in CholU patients. Formalin-fixed, paraffin-embedded biopsies were stained to explore sweat leakage and tight junction protein expression. Dermcidin staining was not found outside the sweat glands. In the secretory coils of sweat glands, the distribution of claudin-3 and -10b as well as occludin was altered, but the zonula occludens-1 location was unchanged. In all, dermcidin and tight junction protein staining suggests an intact barrier with reduced sweat production capability in CholU patients. For future studies, an ex vivo skin model for quantification of sweat secretion was established, in which sweat secretion could be pharmacologically stimulated or blocked. This ex vivo model will be used to further investigate sweat gland function in CholU patients and decipher the underlying pathomechanism(s).


Assuntos
Glândulas Sudoríparas , Suor , Junções Íntimas , Humanos , Glândulas Sudoríparas/metabolismo , Feminino , Junções Íntimas/metabolismo , Masculino , Suor/metabolismo , Adulto , Pessoa de Meia-Idade , Urticária/metabolismo , Urticária/patologia , Sudorese , Pele/metabolismo , Pele/patologia
5.
Am J Physiol Regul Integr Comp Physiol ; 326(6): R588-R598, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38682241

RESUMO

Type 2 diabetes (T2D) is associated with reduced whole body sweating during exercise-heat stress. However, it is unclear if this impairment is related to exercise intensity and whether it occurs uniformly across body regions. We evaluated whole body (direct calorimetry) and local (ventilated-capsule technique; chest, back, forearm, thigh) sweat rates in physically active men with type 2 diabetes [T2D; aged 59 (7) yr; V̇o2peak 32.3 (7.6) mL·kg-1·min-1; n = 26; HbA1c 5.1%-9.1%] and without diabetes [Control; aged 61 (5) yr; V̇o2peak 37.5 (5.4) mL·kg-1·min-1; n = 26] during light- (∼40% V̇o2peak), moderate- (∼50% V̇o2peak), and vigorous- (∼65% V̇o2peak) intensity exercise (elicited by fixing metabolic heat production at ∼150, 200, 250 W·m-2, respectively) in 40°C, ∼17% relative humidity. Whole body sweating was ∼11% (T2D: Control mean difference [95% confidence interval]: -37 [-63, -12] g·m-2·h-1) and ∼13% (-50 [-76, -25] g·m-2·h-1) lower in the T2D compared with the Control group during moderate- and vigorous- (P ≤ 0.001) but not light-intensity exercise (-21 [-47, 4] g·m-2·h-1; P = 0.128). Consequently, the diabetes-related reductions in whole body sweat rate were 2.3 [1.6, 3.1] times greater during vigorous relative to light exercise (P < 0.001). Furthermore, these diabetes-related impairments in local sweating were region-specific during vigorous-intensity exercise (group × region interaction: P = 0.024), such that the diabetes-related reduction in local sweat rate at the trunk (chest, back) was 2.4 [1.2, 3.7] times greater than that at the limbs (thigh, arm). In summary, when assessed under hot, dry conditions, diabetes-related impairments in sweating are exercise intensity-dependent and greater at the trunk compared with the limbs.NEW & NOTEWORTHY This study evaluates the influence of exercise intensity on decrements in whole body sweating associated with type 2 diabetes. Furthermore, it investigates whether diabetes-related sweating impairments were exhibited uniformly or heterogeneously across body regions. We found that whole body sweating was attenuated in the type 2 diabetes group relative to control participants during moderate- and vigorous-intensity exercise but not light-intensity exercise; impairments were largely mediated by reduced sweating at the trunk rather than the limbs.


Assuntos
Diabetes Mellitus Tipo 2 , Exercício Físico , Sudorese , Humanos , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/metabolismo , Masculino , Pessoa de Meia-Idade , Exercício Físico/fisiologia , Idoso , Estudos de Casos e Controles , Regulação da Temperatura Corporal
6.
J Appl Physiol (1985) ; 136(6): 1440-1449, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38660730

RESUMO

The purpose of this study was to investigate the influence of biological sex, independent of differences in aerobic fitness and body fatness, on the change in gastrointestinal temperature (ΔTgi) and whole body sweat rate (WBSR) of children exercising under uncompensable heat stress. Seventeen boys (means ± SD; 13.7 ± 1.3 yr) and 18 girls (13.7 ± 1.4 yr) walked for 45 min at a fixed rate of metabolic heat production per kg body mass (8 W·kg-1) in 40°C and 30% relative humidity. Sex and peak oxygen consumption (V̇o2peak) were entered into a Bayesian hierarchical general additive model (HGAM) for Tgi. Sex, V̇o2peak, and the evaporative requirement for heat balance (Ereq) were entered into a Bayesian hierarchical linear regression for WBSR. For 26 (12 M and 14 F) of the 35 children with measured body composition, body fat percentage was entered in a separate HGAM and hierarchical linear regression for Tgi and WBSR, respectively. Conditional on sex-specific mean V̇o2peak, ΔTgi was 1.00°C [90% credible intervals (Crl): 0.84, 1.16] for boys and 1.17°C [1.01, 1.33] for girls, with a difference of 0.17°C [-0.39, 0.06]. When sex differences in V̇o2peak were accounted for, the difference in ΔTgi between boys and girls was 0.01°C [-0.25, 0.22]. The difference in WBSR between boys and girls was 0.03 L·h-1 [-0.02, 0.07], when isolated from differences in Ereq. The difference in ΔTgi between boys and girls was -0.10°C [-0.38, 0.17] when sex differences in body fat (%) were accounted for. Biological sex did not independently influence the ΔTgi and WBSR of children exercising under uncompensable heat stress.NEW & NOTEWORTHY Limited studies have investigated the thermoregulatory responses of boys and girls exercising under uncompensable heat stress. Boys and girls often differ in physiological characteristics other than biological sex, such as aerobic fitness and body fat percentage, which may confound interpretations. We investigated the influence of biological sex on exercise thermoregulation in children, independent of differences in aerobic fitness and body fatness.


Assuntos
Regulação da Temperatura Corporal , Exercício Físico , Sudorese , Humanos , Feminino , Masculino , Sudorese/fisiologia , Exercício Físico/fisiologia , Adolescente , Criança , Regulação da Temperatura Corporal/fisiologia , Temperatura Corporal/fisiologia , Consumo de Oxigênio/fisiologia , Resposta ao Choque Térmico/fisiologia , Caracteres Sexuais , Teorema de Bayes , Temperatura Alta , Fatores Sexuais , Transtornos de Estresse por Calor/fisiopatologia , Composição Corporal/fisiologia
7.
Menopause ; 31(6): 484-493, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38595299

RESUMO

OBJECTIVES: Vasomotor symptoms (VMS), including hot flashes and night sweats, are hallmark symptoms of the menopause transition. Previous research has documented greater frequency, duration, and severity of VMS in Black women compared with women from other racial/ethnic groups, even after accounting for other factors. This analysis examined the association between discrimination and VMS and the extent to which discrimination accounts for the disproportionate burden of VMS in Black women. METHODS: Using available discrimination and VMS data from the SWAN cohort study (n = 2,377, 48% White, 32% Black, 6% Japanese, 4% Chinese, and 9% Hispanic women) followed approximately yearly in midlife from premenopause (42-52 y) through postmenopause (~20 y), we assessed concurrent associations between discrimination and VMS frequency in the past 2 weeks using weighted generalized mixed models. We also assessed associations between chronic discrimination across first four visits and VMS trajectories from premenopause to postmenopause using weighted multinomial logistic regression. Models were adjusted for known risk factors for VMS. RESULTS: Higher levels of discrimination were associated with concurrent reporting of any (odds ratio [OR], 1.57 [1.31-1.89]) and frequent (≥6 d) VMS (OR, 1.55 [1.21-1.99]). After adjustment, associations remained significant for any (OR, 1.30 [1.09-1.54]) but not frequent VMS. For any VMS trajectories, chronic discrimination was associated with "continuously high" (OR, 1.69 [1.03-2.77]) and "high pre-FMP-decline post-FMP" (OR, 1.70 [1.01-2.88]) versus "FMP-onset low" trajectories. After adjusting for discrimination, odds of reporting any, frequent, and of being in the "continuously high" any VMS trajectory remained elevated for Black versus White women. CONCLUSIONS: Discrimination is associated with greater concurrent risk of any (but not frequent) VMS, and chronic discrimination is associated with a continuously high reporting of any VMS over time, independent of known risk factors. Adjusting for discrimination attenuates but does not eliminate the increased risk of VMS for Black women.


Assuntos
Negro ou Afro-Americano , Fogachos , Menopausa , Saúde da Mulher , Humanos , Feminino , Fogachos/etnologia , Fogachos/epidemiologia , Pessoa de Meia-Idade , Negro ou Afro-Americano/estatística & dados numéricos , Menopausa/fisiologia , Adulto , Fatores de Risco , População Branca/estatística & dados numéricos , Estudos de Coortes , Sudorese , Estados Unidos/epidemiologia , Sistema Vasomotor/fisiopatologia , Pós-Menopausa/fisiologia , Asiático/estatística & dados numéricos , Hispânico ou Latino/estatística & dados numéricos
8.
Int J Biol Macromol ; 267(Pt 2): 131658, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38636759

RESUMO

Moisture evaporation plays a crucial role in thermal management of human body, particularly in perspiration process. However, current fabrics aim for sweat removal and takes little account of basic thermo-regulation of sweat, resulted in their limited evaporation capacity and heat dissipation at moderate/intense scenarios. In this study, a hygroscopic cooling (h-cool) fabric based on multi-functional design, for personal perspiration management, was described. By using economic and effective weaving technology, directional moisture transport routes and heat conductive pathways were incorporated in the construct. The resultant fabric showed 10 times greater one-way transport index higher than cotton, Dri-FIT and Coolswitch fabrics, which contributed to highly enhanced evaporation ability (∼4.5 times than cotton), not merely liquid diffusion. As a result, h-cool fabric performed 2.1-4.2 °C cooling efficacy with significantly reduced sweat consuming than cotton, Dri-FIT and Coolswitch fabrics in the artificial sweating skin. Finally, the practical applications by actually wearing h-cool fabric showed great evaporative-cooling efficacy during different physical activities. Owing to the excellent thermo-moisture management ability, we expect the novel concept and construct of h-cool fabric can provide promising strategy for developing functional textiles with great "cool" and comfortable "dry" tactile sensation at various daily scenarios.


Assuntos
Suor , Têxteis , Humanos , Suor/química , Temperatura Alta , Molhabilidade , Sudorese
10.
J Therm Biol ; 121: 103833, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38527387

RESUMO

Dairy cows in pasture-based systems are more susceptible to heat stress. Holstein cows have the black or red phenotypes, the latter having lower absorbance of solar radiation. Therefore, the study's objective was to evaluate whether cows with red (R) coats are more resistant than black (B) cows to hot weather in a subtropical climate. R and B lactating Holstein cows were evaluated during the cold and hot seasons for internal and surface temperature and sweating rate. In the cold season, body temperature (n = 9/group) did not differ between groups, but the average superficial temperature (n = 13/group) was lower in R cows (B: 30.9 ± 0.3 °C; RW: 29.6 ± 0.3 °C; p = 0.02). In the hot season, under mild to moderate heat stress, mean body temperature (n = 9/group) of R cows was lower (B: 38.75 ± 0.01 °C; R: 38.62 ± 0.1 °C; p=<0.0001), whereas no difference was observed in superficial temperature (n = 17/group). The maximum internal temperature and sweating rate (n = 11/group), measured in the hot season, and the number of evaluations in hyperthermia in both seasons did not differ. Therefore, there were differences in thermoregulation between phenotypes under mild to moderate heat stress conditions. However, considering that only discrete differences were observed, the red and white coat is unlikely to benefit the Holstein cow's welfare under mild to moderate thermal stress.


Assuntos
Regulação da Temperatura Corporal , Lactação , Estações do Ano , Animais , Bovinos/fisiologia , Feminino , Brasil , Resposta ao Choque Térmico , Temperatura Alta , Temperatura Corporal , Temperatura Baixa , Sudorese
11.
Int J Occup Saf Ergon ; 30(2): 587-598, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38509715

RESUMO

Objectives. This study explores the effects of temperature steps on thermal responses to understand abrupt temperature shifts faced by heat-exposed workers during winter. Methods. Three temperature step changes with three phases (S20: 20-40-20 °C, S30: 10-40-10 °C, S40: 0-40-0 °C) were conducted. Phase 1 took 30 min, phase 2 took 60 min and phase 3 took 40 min. Eleven participants remained sedentary throughout the experiment, and physiological responses, thermal perception and self-reported health symptoms were recorded. Results. In temperature up steps, steady skin temperature and sweating onset were delayed, and heart rate dropped by 10 bpm from S20 to S40. In temperature down steps to cold conditions, individuals transitioned from thermal comfort to discomfort and eventually cold strain. Blood pressure increased in temperature down steps, correlating with temperature step magnitudes. Thermal responses to temperature steps of equal magnitude but opposite directions were asymmetries, which weakened as step magnitude increased. Thermal perceptions responded faster than physiological changes after temperature steps, while self-reported health symptoms lagged behind physiological responses. Conclusions. These findings contribute to expanding basic data to understand the effects of temperature step magnitude and direction.


Assuntos
Temperatura Baixa , Frequência Cardíaca , Temperatura Alta , Temperatura Cutânea , Humanos , Masculino , Temperatura Cutânea/fisiologia , Frequência Cardíaca/fisiologia , Adulto , Pressão Sanguínea/fisiologia , Sudorese/fisiologia , Feminino , Percepção/fisiologia , Sensação Térmica/fisiologia , Adulto Jovem
13.
Nutrients ; 16(6)2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38542815

RESUMO

Exercise can disrupt the fluid balance, hindering performance and athlete health. Limited data exist on fluid balance responses in varying climates, sexes, and ages. This study aimed to measure and compare fluid balance and urine values among elite soccer players during training at high and low temperatures, examining the differences between sexes, playing positions, and competitive levels within men's soccer. During the 2022-2023 competitive season, a descriptive observational study was conducted on 87 soccer players from an elite Spanish soccer team. The study found that none of the groups exceeded weight loss values of 1.5% of their body mass. Additionally, the soccer players studied experienced higher weight loss, fluid intake, and a higher sweat rate (SR) during summer training compared to winter training. During the summer, male U23-21 soccer players exhibited higher levels of weight loss, fluid intake, and a higher SR compared to female soccer players or the U19-17 male category. No significant differences were found between playing positions. In conclusion, differences in the fluid balance were observed based on the climatic conditions, competitive level, and sex.


Assuntos
Futebol , Humanos , Masculino , Feminino , Futebol/fisiologia , Equilíbrio Hidroeletrolítico/fisiologia , Suor , Sudorese , Redução de Peso
15.
J Affect Disord ; 354: 376-384, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38503358

RESUMO

BACKGROUND: We investigated the association between vasomotor symptoms (VMSs) and the onset of depressive symptoms among premenopausal women. METHODS: This cross-sectional study included 4376 premenopausal women aged 42-52 years, and the cohort study included 2832 women without clinically relevant depressive symptoms at baseline. VMSs included the symptoms of hot flashes and night sweats. Depressive symptoms were evaluated using the Center for Epidemiological Studies Depression Scale; a score of ≥16 was considered to define clinically relevant depressive symptoms. RESULTS: Premenopausal Women with VMSs at baseline exhibited a higher prevalence of depressive symptoms compared with women without VMSs at baseline (multivariable-adjusted prevalence ratio 1.76, 95 % confidence interval [CI] 1.47-2.11). Among the 2832 women followed up (median, 6.1 years), 406 developed clinically relevant depressive symptoms. Women with versus without VMSs had a significantly higher risk of developing clinically relevant depressive symptoms (multivariable-adjusted hazard ratio, 1.72; 95 % CI 1.39-2.14). VMS severity exhibited a dose-response relationship with depressive symptoms (P for trend <0.05). LIMITATIONS: Self-reported questionnaires were only used to obtain VMSs and depressive symptoms, which could have led to misclassification. We also could not directly measure sex hormone levels. CONCLUSIONS: Even in the premenopausal stage, women who experience hot flashes or night sweats have an increased risk of present and developed clinically relevant depressive symptoms. It is important to conduct mental health screenings and provide appropriate support to middle-aged women who experience early-onset VMSs.


Assuntos
Fogachos , Menopausa , Pessoa de Meia-Idade , Feminino , Humanos , Fogachos/epidemiologia , Depressão/epidemiologia , Estudos de Coortes , Estudos Transversais , Sudorese
16.
Menopause ; 31(4): 342-354, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38471077

RESUMO

IMPORTANCE: Vasomotor symptoms (VMS) affect many postmenopausal persons and impact sleep and quality of life. OBJECTIVE: This systematic review examines the literature describing the safety and efficacy of neurokinin-3 receptor antagonists approved and in development for postmenopausal persons with VMS. EVIDENCE REVIEW: A search of MEDLINE, EMBASE, and International Pharmaceutical Abstracts was conducted using the search terms and permutations of neurokinin-3 receptor antagonist, elinzanetant, fezolinetant, and osanetant. Inclusion criteria of reporting on efficacy or safety of fezolinetant, elinzanetant, or osanetant; studies in participants identifying as female; full record in English; and primary literature were applied. Abstract-only records were excluded. Extracted data were synthesized to allow comparison of reported study characteristics, efficacy outcomes, and safety events. Eligible records were evaluated for risk of bias via the Cochrane Risk of Bias 2 tool for randomized studies and the Grading of Recommendations Assessment, Development and Evaluation system was used. This study was neither funded nor registered. FINDINGS: The search returned 191 records; 186 were screened after deduplication. Inclusion criteria were met by six randomized controlled trials (RCT), four reported on fezolinetant, and two reported on elinzanetant. One record was a post hoc analysis of a fezolinetant RCT. An additional study was identified outside the database search. Three fezolinetant RCT demonstrated a reduction in VMS frequency/severity, improvement in Menopause-Specific Quality of Life scores, and improvement in sleep quality at weeks 4 and 12 compared with placebo without serious adverse events. The two RCT on elinzanetant also showed improvements in VMS frequency and severity. All eight records evaluated safety through treatment-emergent adverse events; the most common adverse events were COVID-19, headache, somnolence, and gastrointestinal. Each record evaluated had a low risk of bias. There is a strong certainty of evidence as per the Grading of Recommendations Assessment, Development and Evaluation system. CONCLUSIONS AND RELEVANCE: Because of the high-quality evidence supporting the efficacy of fezolinetant and elinzanetant, these agents may be an effective option with mild adverse events for women seeking nonhormone treatment of VMS.


Assuntos
Compostos Heterocíclicos com 2 Anéis , Fogachos , Menopausa , Piperidinas , Receptores da Neurocinina-3 , Sudorese , Tiadiazóis , Sistema Vasomotor , Feminino , Humanos , Compostos Heterocíclicos com 2 Anéis/farmacologia , Compostos Heterocíclicos com 2 Anéis/uso terapêutico , Menopausa/efeitos dos fármacos , Menopausa/fisiologia , Receptores da Neurocinina-3/antagonistas & inibidores , Tiadiazóis/química , Tiadiazóis/uso terapêutico , Piperidinas/farmacologia , Piperidinas/uso terapêutico , Fogachos/tratamento farmacológico , Sudorese/efeitos dos fármacos , Sistema Vasomotor/efeitos dos fármacos , Sistema Vasomotor/fisiopatologia
17.
Environ Sci Technol ; 58(15): 6532-6539, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38538556

RESUMO

Sweating regulates the body temperature in extreme environments or during exercise. Here, we investigate the evaporative heat transfer of a sweat droplet at the microscale to unveil how the evaporation complexity of a sweat droplet would affect the body's ability to cool under specific environmental conditions. Our findings reveal that, depending on the relative humidity and temperature levels, sweat droplets experience imperfect evaporation dynamics, whereas water droplets evaporate perfectly at equivalent ambient conditions. At low humidity, the sweat droplet fully evaporates and leaves a solid deposit, while at high humidity, the droplet never reaches a solid deposit and maintains a liquid phase residue for both low and high temperatures. This unprecedented evaporation mechanism of a sweat droplet is attributed to the intricate physicochemical properties of sweat as a biofluid. We suppose that the sweat residue deposited on the surface by evaporation is continuously absorbing the surrounding moisture. This route leads to reduced evaporative heat transfer, increased heat index, and potential impairment of the body's thermoregulation capacity. The insights into the evaporative heat transfer dynamics at the microscale would help us to improve the knowledge of the body's natural cooling mechanism with practical applications in healthcare, materials science, and sports science.


Assuntos
Suor , Sudorese , Temperatura Alta , Regulação da Temperatura Corporal/fisiologia , Temperatura
18.
Blood Press Monit ; 29(3): 109-118, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38299995

RESUMO

High blood pressure (hypertension), is a common medical condition, affecting millions of people and is associated with significant health risks. Exercise has been suggested to manage hypertension by inducing sweating and the corresponding loss of sodium and water from the body.Thus, a variety of epidemiological and clinical studies have been conducted to investigate the relationship between sweating and exercise-induced blood pressure reduction and its impacts on hypertension. The mechanisms underlying exercise-induced blood pressure reduction are complex and still not fully understood. However, several pathways have been suggested, including the loss of sodium and water through sweat, a decrease in peripheral resistance, and an improvement in endothelial function in the blood vessels. The decrease in sodium and water content in the body associated with sweating may result in a reduction in blood volume and thus a decrease in blood pressure. Moreover, the reduction in peripheral resistance is thought to be mediated by the activation of the nitric oxide synthase pathway and the release of vasodilators such as prostacyclin and bradykinin, which lead to vasodilation and, thus, a reduction in blood pressure. In conclusion, exercise-induced sweating and consequent sodium and water loss appear to be a reliable biological link to the blood pressure-reducing effects of exercise in hypertensive individuals. Additionally, the mechanisms underlying exercise-induced blood pressure reduction are complex and involve several biological pathways in the cardiovascular system. Therefore, understanding the role of sweat production in blood pressure management is important for developing effective exercise interventions to prevent and manage hypertension.


Assuntos
Pressão Sanguínea , Exercício Físico , Hipertensão , Sudorese , Humanos , Hipertensão/fisiopatologia
19.
J Physiol ; 602(5): 875-890, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38367251

RESUMO

Synthetic progestins in oral contraceptives are thought to blunt heat dissipation by reducing skin blood flow and sweating. However, whether progestin-releasing intrauterine devices (IUDs) modulate heat loss during exercise-heat stress is unknown. We used direct calorimetry to measure whole-body total (dry + evaporative) heat loss in young, physically active women (mean (SD); aged 24 (4) years, V ̇ O 2 peak ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{peak}}}}$ 39.3 (5.3) ml/kg/min) with (IUD; n = 19) and without (Control; n = 17) IUDs in the follicular and luteal phases of the menstrual cycle during light- and moderate-intensity exercise at fixed rates of heat production (∼175 and ∼275 W/m2 ) in 30°C, ∼21% relative humidity. Between-group and -phase differences were evaluated using traditional hypothesis testing and statistical equivalence testing within pre-determined bounds (±11 W/m2 ; difference required to elicit a ±0.3°C difference in core temperature over 1 h) in each exercise bout. Whole-body total heat loss was statistically equivalent between groups within ±11 W m-2 (IUD-Control [90% CIs]; Light: -2 [-8, 5] W/m2 , P = 0.007; Moderate: 0 [-6, 6] W/m2 , P = 0.002), as were dry and evaporative heat loss (P ≤ 0.023), except for evaporative heat loss during moderate-intensity exercise (equivalence: P = 0.063, difference: P = 0.647). Whole-body total and evaporative heat loss were not different between phases (P ≥ 0.267), but dry heat loss was 3 [95% CIs: 1, 5] W/m2 greater in the luteal phase (P ≤ 0.022). Despite this, all whole-body heat loss outcomes were equivalent between phases (P ≤ 0.003). These findings expand our understanding of the factors that modulate heat exchange in women and provide valuable mechanistic insight of the role of endogenous and exogenous female sex hormones in thermoregulation. KEY POINTS: Progestin released by hormonal intrauterine devices (IUDs) may negatively impact heat dissipation during exercise by blunting skin blood flow and sweating. However, the influence of IUDs on thermoregulation has not previously been assessed. We used direct calorimetry to show that IUD users and non-users display statistically equivalent whole-body dry and evaporative heat loss, body heat storage and oesophageal temperature during moderate- and high-intensity exercise in a warm, dry environment, indicating that IUDs do not appear to compromise exercise thermoregulation. However, within IUD users and non-users, dry heat loss was increased and body heat storage and oesophageal temperature were reduced in the luteal compared to the follicular phase of the menstrual cycle, though these effects were small and unlikely to be practically meaningful. Together, these findings expand our understanding of the factors that modulate heat exchange in women and have important practical implications for the design of future studies of exercise thermoregulation.


Assuntos
Temperatura Alta , Progestinas , Feminino , Humanos , Regulação da Temperatura Corporal/fisiologia , Temperatura Corporal/fisiologia , Exercício Físico/fisiologia , Sudorese
20.
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