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1.
Int Wound J ; 21(7): e14957, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38994923

RESUMEN

Prolonged mechanical loading of the skin and underlying soft tissue cause pressure ulceration. The use of special support surfaces are key interventions in pressure ulcer prevention. They modify the degree and duration of soft tissue deformation and have an impact on the skin microclimate. The objective of this randomized cross-over trial was to compare skin responses and comfort after lying for 2.5 h supine on a support surface with and without a coverlet that was intended to assist with heat and moisture removal at the patient/surface interface. In addition, physiological saline solution was administered to simulate an incontinence episode on the mattress next to the participants' skin surface. In total, 12 volunteers (mean age 69 years) with diabetes mellitus participated. After loading, skin surface temperature, stratum corneum hydration and skin surface pH increased, whereas erythema and structural stiffness decreased at the sacral area. At the heel skin area, temperature, erythema, and stratum corneum hydration increased. These results indicate occlusion and soft tissue deformation which was aggravated by the saline solution. The differences in skin response showed only minor differences between the support surface with or without the coverlet.


Asunto(s)
Lechos , Estudios Cruzados , Talón , Úlcera por Presión , Humanos , Anciano , Úlcera por Presión/prevención & control , Masculino , Femenino , Persona de Mediana Edad , Soporte de Peso/fisiología , Anciano de 80 o más Años , Temperatura Cutánea/fisiología
3.
Physiol Rep ; 12(11): e16107, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38849294

RESUMEN

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.


Asunto(s)
Calor Extremo , Frecuencia Cardíaca , Humanos , Masculino , Adulto , Sicilia , Frecuencia Cardíaca/fisiología , Calor Extremo/efectos adversos , Sudoración/fisiología , Temperatura Corporal/fisiología , Regulación de la Temperatura Corporal/fisiología , Temperatura Cutánea/fisiología , Calor/efectos adversos
4.
Sci Rep ; 14(1): 10449, 2024 05 07.
Artículo en Inglés | MEDLINE | ID: mdl-38714775

RESUMEN

The body temperature of infants at equilibrium with their surroundings is balanced between heat production from metabolism and the transfer of heat to the environment. Total heat production is related to body size, which is closely related to metabolic rate and oxygen consumption. Body temperature control is a crucial aspect of neonatal medicine but we have often struggled with temperature measures. Contactless infrared thermography (IRT) is useful for vulnerable neonates and may be able to assess their spontaneous thermal metabolism. The present study focused on heat oscillations and their cause. IRT was used to measure the skin temperature every 15 s of neonates in an incubator. We analyzed the thermal data of 27 neonates (32 measurements), calculated the average temperature within specified regions, and extracted two frequency components-Components A and B-using the Savitzky-Golay method. Furthermore, we derived an equation describing the cycle-named cycle T-for maintaining body temperature according to body weight. A positive correlation was observed between cycle T and Component B (median [IQR]: 368 [300-506] s). This study sheds light on the physiological thermoregulatory function of newborns and will lead to improved temperature management methods for newborns, particularly premature, low-birth-weight infants.


Asunto(s)
Regulación de la Temperatura Corporal , Termografía , Humanos , Recién Nacido , Termografía/métodos , Regulación de la Temperatura Corporal/fisiología , Femenino , Masculino , Monitoreo Fisiológico/métodos , Temperatura Corporal/fisiología , Temperatura Cutánea/fisiología
5.
Sensors (Basel) ; 24(9)2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38732798

RESUMEN

Photoplethysmography (PPG) is a non-invasive method used for cardiovascular monitoring, with multi-wavelength PPG (MW-PPG) enhancing its efficacy by using multiple wavelengths for improved assessment. This study explores how contact force (CF) variations impact MW-PPG signals. Data from 11 healthy subjects are analyzed to investigate the still understudied specific effects of CF on PPG signals. The obtained dataset includes simultaneous recording of five PPG wavelengths (470, 525, 590, 631, and 940 nm), CF, skin temperature, and the tonometric measurement derived from CF. The evolution of raw signals and the PPG DC and AC components are analyzed in relation to the increasing and decreasing faces of the CF. Findings reveal individual variability in signal responses related to skin and vasculature properties and demonstrate hysteresis and wavelength-dependent responses to CF changes. Notably, all wavelengths except 631 nm showed that the DC component of PPG signals correlates with CF trends, suggesting the potential use of this component as an indirect CF indicator. However, further validation is needed for practical application. The study underscores the importance of biomechanical properties at the measurement site and inter-individual variability and proposes the arterial pressure wave as a key factor in PPG signal formation.


Asunto(s)
Fotopletismografía , Humanos , Fotopletismografía/métodos , Masculino , Adulto , Femenino , Procesamiento de Señales Asistido por Computador , Temperatura Cutánea/fisiología , Adulto Joven
6.
PLoS One ; 19(5): e0300373, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38696403

RESUMEN

Captive and domestic animals are often required to engage in physical activity initiated or organised by humans, which may impact their body temperature, with consequences for their health and welfare. This is a particular concern for animals such as elephants that face thermoregulatory challenges because of their body size and physiology. Using infrared thermography, we measured changes in skin temperature associated with two types of physical activity in ten female Asian elephants (Elephas maximus) at an eco-tourism lodge in Nepal. Six elephants took part in an activity relatively unfamiliar to the elephants-a polo tournament-and four participated in more familiar ecotourism activities. We recorded skin temperatures for four body regions affected by the activities, as well as an average skin temperature. Temperature change was used as the response variable in the analysis and calculated as the difference in elephant temperature before and after activity. We found no significant differences in temperature change between the elephants in the polo-playing group and those from the non-polo playing group. However, for both groups, when comparing the average skin body temperature and several different body regions, we found significant differences in skin temperature change before and after activity. The ear pinna was the most impacted region and was significantly different to all other body regions. This result highlights the importance of this region in thermoregulation for elephants during physical activity. However, as we found no differences between the average body temperatures of the polo and non-polo playing groups, we suggest that thermoregulatory mechanisms can counteract the effects of both physical activities the elephants engaged in.


Asunto(s)
Elefantes , Temperatura Cutánea , Animales , Elefantes/fisiología , Femenino , Temperatura Cutánea/fisiología , Condicionamiento Físico Animal/fisiología , Temperatura Corporal/fisiología , Regulación de la Temperatura Corporal/fisiología , Termografía/métodos
7.
J Appl Physiol (1985) ; 136(6): 1364-1375, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38572540

RESUMEN

Cold exposure increases blood pressure (BP) and salivary flow rate (SFR). Increased cold-induced SFR would be hypothesized to enhance oral nitrate delivery for reduction to nitrite by oral anaerobes and to subsequently elevate plasma [nitrite] and nitric oxide bioavailability. We tested the hypothesis that dietary nitrate supplementation would increase plasma [nitrite] and lower BP to a greater extent in cool compared with normothermic conditions. Twelve males attended the laboratory on four occasions. Baseline measurements were completed at 28°C. Subsequently, participants ingested 140 mL of concentrated nitrate-rich (BR; ∼13 mmol nitrate) or nitrate-depleted (PL) beetroot juice. Measurements were repeated over 3 h at either 28°C (Norm) or 20°C (Cool). Mean skin temperature was lowered compared with baseline in PL-Cool and BR-Cool. SFR was greater in BR-Norm, PL-Cool, and BR-Cool than PL-Norm. Plasma [nitrite] at 3 h was higher in BR-Cool (592 ± 239 nM) versus BR-Norm (410 ± 195 nM). Systolic BP (SBP) at 3 h was not different between PL-Norm (117 ± 6 mmHg) and BR-Norm (113 ± 9 mmHg). SBP increased above baseline at 1, 2, and 3 h in PL-Cool but not BR-Cool. These results suggest that BR consumption is more effective at increasing plasma [nitrite] in cool compared with normothermic conditions and blunts the rise in BP following acute cool air exposure, which might have implications for attenuating the increased cardiovascular strain in the cold.NEW & NOTEWORTHY Compared with normothermic conditions, acute nitrate ingestion increased plasma [nitrite], a substrate for oxygen-independent nitric oxide generation, to a greater extent during cool air exposure. Systolic blood pressure was increased during cool air exposure in the placebo condition with this cool-induced blood pressure increase attenuated after acute nitrate ingestion. These findings improve our understanding of environmental factors that influence nitrate metabolism and the efficacy of nitrate supplementation to lower blood pressure.


Asunto(s)
Presión Sanguínea , Frío , Estudios Cruzados , Nitratos , Humanos , Masculino , Nitratos/administración & dosificación , Nitratos/sangre , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Método Doble Ciego , Adulto , Adulto Joven , Nitritos/sangre , Óxido Nítrico/metabolismo , Suplementos Dietéticos , Beta vulgaris , Temperatura Cutánea/efectos de los fármacos , Temperatura Cutánea/fisiología , Jugos de Frutas y Vegetales
9.
Scand J Trauma Resusc Emerg Med ; 32(1): 35, 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38664809

RESUMEN

BACKGROUND: Use of a vapor barrier in the prehospital care of cold-stressed or hypothermic patients aims to reduce evaporative heat loss and accelerate rewarming. The application of a vapor barrier is recommended in various guidelines, along with both insulating and wind/waterproof layers and an active external rewarming device; however, evidence of its effect is limited. This study aimed to investigate the effect of using a vapor barrier as the inner layer in the recommended "burrito" model for wrapping hypothermic patients in the field. METHODS: In this, randomized, crossover field study, 16 healthy volunteers wearing wet clothing were subjected to a 30-minute cooling period in a snow chamber before being wrapped in a model including an active heating source either with (intervention) or without (control) a vapor barrier. The mean skin temperature, core temperature, and humidity in the model were measured, and the shivering intensity and thermal comfort were assessed using a subjective questionnaire. The mean skin temperature was the primary outcome, whereas humidity and thermal comfort were the secondary outcomes. Primary outcome data were analyzed using analysis of covariance (ANCOVA). RESULTS: We found a higher mean skin temperature in the intervention group than in the control group after approximately 25 min (p < 0.05), and this difference persisted for the rest of the 60-minute study period. The largest difference in mean skin temperature was 0.93 °C after 60 min. Humidity levels outside the vapor barrier were significantly higher in the control group than in the intervention group after 5 min. There were no significant differences in subjective comfort. However, there was a consistent trend toward increased comfort in the intervention group compared with the control group. CONCLUSIONS: The use of a vapor barrier as the innermost layer in combination with an active external heat source leads to higher mean skin rewarming rates in patients wearing wet clothing who are at risk of accidental hypothermia. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05779722.


Asunto(s)
Estudios Cruzados , Servicios Médicos de Urgencia , Hipotermia , Recalentamiento , Humanos , Recalentamiento/métodos , Masculino , Femenino , Adulto , Servicios Médicos de Urgencia/métodos , Hipotermia/prevención & control , Temperatura Cutánea/fisiología , Adulto Joven , Frío
10.
Eur Eat Disord Rev ; 32(4): 700-717, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38446505

RESUMEN

Eating disorders (ED) are serious psychiatric illnesses, with no everyday support to intervene on the high rates of relapse. Understanding physiological indices that can be measured by wearable sensor technologies may provide new momentary interventions for individuals with ED. This systematic review, searching large databases, synthesises studies investigating peripheral physiological (PP) indices commonly included in wearable wristbands (heart rate [HR], heart rate variability [HRV], electrodermal activity [EDA], peripheral skin temperature [PST], and acceleration) in ED. Inclusion criteria included: (a) full peer-reviewed empirical articles in English; (b) human participants with active ED; and (c) containing one of five wearable physiological measures. Kmet risk of bias was assessed. Ninety-four studies were included (Anorexia nervosa [AN; N = 4418], bulimia nervosa [BN; N = 916], binge eating disorder [BED; N = 1604], other specified feeding and eating disorders [OSFED; N = 424], and transdiagnostic [N = 47]). Participants with AN displayed lower HR and EDA and higher HRV compared to healthy individuals. Those with BN showed higher HRV, and lower EDA and PST compared to healthy individuals. Other ED and Transdiagnostic samples showed mixed results. PP differences are indicated through various assessments in ED, which may suggest diagnostic associations, although more studies are needed to validate observed patterns. Results suggest important therapeutic potential for PP in ED, and larger studies including diverse participants and diagnostic groups are needed to fully uncover their role in ED.


Asunto(s)
Trastornos de Alimentación y de la Ingestión de Alimentos , Frecuencia Cardíaca , Humanos , Trastornos de Alimentación y de la Ingestión de Alimentos/fisiopatología , Frecuencia Cardíaca/fisiología , Respuesta Galvánica de la Piel/fisiología , Dispositivos Electrónicos Vestibles , Temperatura Cutánea/fisiología
11.
J Tissue Viability ; 33(2): 305-311, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38553355

RESUMEN

OBJECTIVE: this study was undertaken to evaluate the efficacy of multilayer polyurethane foam with silicone (MPF) compared to transparent polyurethane film (TPF) dressings in the control of heel skin microclimate (temperature and moisture) of hospitalized patients undergoing elective surgeries. METHOD: the study took of a secondary analysis of a randomized self-controlled trial, involving patients undergoing elective surgical procedure of cardiac and gastrointestinal specialties in a university hospital in southern Brazil, from March 2019 to February 2020. Patients served as their own control, with their heels randomly allocated to either TPF (control) or MPF (intervention). Skin temperature was measured using a digital infrared thermometer; and moisture determined through capacitance, at the beginning and end of surgery. The study was registered in the Brazilian Registry of Clinical Trials: RBR-5GKNG5. RESULTS: significant difference in the microclimate variables were observed when the groups (intervention and control) and the timepoint of measurement (beginning and end of surgery) were compared. When assessing temperature, an increase (+3.3 °C) was observed with TPF and a decrease (-7.4 °C) was recorded with MPF. Regarding skin moisture, an increase in moisture (+14.6 AU) was recorded with TPF and a slight decrease (-0.3 AU) with MPF. CONCLUSIONS: The findings of this study suggest that MPF is more effective than TPF in controlling skin microclimate (temperature and moisture) in heels skin of hospitalized patients undergoing elective surgeries. However, this control should be better investigated in other studies.


Asunto(s)
Talón , Microclima , Humanos , Femenino , Masculino , Persona de Mediana Edad , Brasil , Anciano , Temperatura Cutánea/fisiología , Vendajes/normas , Vendajes/estadística & datos numéricos , Poliuretanos , Adulto
12.
Mater Horiz ; 11(10): 2428-2437, 2024 05 20.
Artículo en Inglés | MEDLINE | ID: mdl-38441176

RESUMEN

Monitoring of arterial blood pressure via cuffless pulse waveform measurement at the wrist has an important clinical value for the early diagnosis and prevention of cardiovascular disease. However, accurate measurement of the radial pulse waveform is challenging owing to its subtle, wideband, and preload-dependent variation characteristics. Evidence shows that uncertainties or variations of wearing pressure and skin temperature can cause artifact signals in wrist pulse measurements, thus degrading blood pressure estimate accuracy and hindering precise clinical diagnosis. Herein, we report a flexible multisensory pulse sensor utilizing natural piezo-thermic transduction of human skin in conjunction with thin-film thermistors for the accurately measuring radial artery pulse waves with high fidelity and good anti-artifact performance. The flexible pulse sensor achieved a wide pressure measuring range (228.2 kPa), low detection limit (4 Pa), good linearity (R2 = 0.999), low hysteresis (2.45%), fast response (88 ms), and good durability and stability, thereby enabling accurate pulse measurement with high fidelity. The pulse sensor also monolithically integrated the simultaneous detections of skin temperature and wearing pressure for resisting artifact effects in pulse measurements. Through the fusion of multiple features extracted from the pulse waveform, wearing pressure, skin temperature and user's personal physical characteristics using an efficient multilayer perceptron, blood pressure is accurately estimated and good generalizability is achieved.


Asunto(s)
Dispositivos Electrónicos Vestibles , Humanos , Masculino , Temperatura Cutánea/fisiología , Presión Sanguínea/fisiología , Determinación de la Presión Sanguínea/métodos , Determinación de la Presión Sanguínea/instrumentación , Adulto , Femenino , Pulso Arterial
13.
Int J Occup Saf Ergon ; 30(2): 587-598, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38509715

RESUMEN

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.


Asunto(s)
Frío , Frecuencia Cardíaca , Calor , Temperatura Cutánea , Humanos , Masculino , Temperatura Cutánea/fisiología , Frecuencia Cardíaca/fisiología , Adulto , Presión Sanguínea/fisiología , Sudoración/fisiología , Femenino , Percepción/fisiología , Sensación Térmica/fisiología , Adulto Joven
14.
Work ; 78(3): 601-612, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38339951

RESUMEN

BACKGROUND: Using medical gowns with high protection against COVID-19 among healthcare workers (HCWs) may limit heat exchange, resulting in physiological challenges. OBJECTIVE: This study aimed to compare the physiological and neurophysiological responses of female HCWs when using two typical medical gowns at different temperatures during the COVID-19 pandemic. METHODS: Twenty healthy female HCWs participated in this study. Participants wore two types of medical gowns: Spunbond gown (SG) and laminate gown (LG). They walked on a treadmill in a controlled climate chamber for 30 minutes at three different temperatures (24, 28, and 32°C). Heart rate (HR), skin surface temperature (ST), clothing surface temperature (CT), ear temperature (ET), blood oxygen percentage (SaO2), galvanic skin response (GSR), and blood pressure were measured before and after walking on a treadmill. The study's results were analyzed using SPSS26. RESULTS: The study found that LG led to an average increase of 0.575°C in CT compared to SG at the same temperatures (P < 0.03). The average HR increased by 6.5 bpm in LG at 28°C compared to SG at a comfortable temperature (P = 0.01). The average ET in SG and GSR in LG at 32°C increased by 0.39°C and 0.25µS, respectively, compared to the comfortable temperature (P < 0.02). CONCLUSION: The study recommends maintaining a comfortable temperature range in hospitals to prevent physiological challenges among HCWs wearing medical gowns with high protection against COVID-19. This is important because using LG, compared to SG, at high temperatures can increase HR, ET, CT, and GSR.


Asunto(s)
COVID-19 , Personal de Salud , Frecuencia Cardíaca , Ropa de Protección , SARS-CoV-2 , Humanos , Femenino , COVID-19/prevención & control , Adulto , Frecuencia Cardíaca/fisiología , Personal de Salud/estadística & datos numéricos , Ropa de Protección/estadística & datos numéricos , Pandemias , Temperatura Cutánea/fisiología , Temperatura , Temperatura Corporal/fisiología , Respuesta Galvánica de la Piel/fisiología
15.
Intensive Crit Care Nurs ; 83: 103652, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38402650

RESUMEN

OBJECTIVE: To investigate the correlation between body temperature and skin surface temperature in intensive care unit patients and to identify specific indicators of skin surface temperature for early fever detection. RESEARCH METHODOLOGY/DESIGN: This pilot study was a prospective, observational investigation conducted at National Cheng Kung University Hospital in Tainan, Taiwan. A total of 54 patients admitted to the Surgical Intensive Care Unit of a tertiary hospital between April and August 2020 were included. Patients utilized the wearable device HEARThremoTM to continuously monitor skin surface temperature and heart rate. Analysis of Variance was applied to identify the association of skin surface temperature with different body temperature groups. The comparison between skin surface temperature and fever over eight time intervals was studied using a generalized estimating equation. RESULTS: In 34 patients (63 %) with a fever (≥38 °C), skin surface temperature increased (P < 0.001) when body temperature increased. The maximum skin surface temperature was significantly associated with fever 180-210 min before the fever events occurred (OR: 2.22, 95 % CI: 1.30-3.80). The mean skin surface temperature was associated with fever 120-150 min before the fever events (OR: 8.70, 95 % CI: 2.08-36.36). CONCLUSIONS: Skin surface temperature can be an important early predictive sign before the onset of fever. Continuous temperature monitoring can detect fever early and initiate treatment in advance. This study serves as a preliminary exploration in this area, laying the groundwork for future comprehensive research. IMPLICATIONS FOR CLINICAL PRACTICE: Continuous monitoring of skin surface temperature empowers nurses to swiftly detect fever, transcending conventional methods. This proactive approach allows for the early identification of physiological abnormalities, facilitating the prompt initiation of further physical assessments and relevant examinations for early treatment commencement.


Asunto(s)
Fiebre , Unidades de Cuidados Intensivos , Temperatura Cutánea , Humanos , Proyectos Piloto , Masculino , Femenino , Estudios Prospectivos , Fiebre/fisiopatología , Fiebre/diagnóstico , Fiebre/etiología , Persona de Mediana Edad , Temperatura Cutánea/fisiología , Anciano , Taiwán , Unidades de Cuidados Intensivos/organización & administración , Adulto , Monitoreo Fisiológico/métodos , Monitoreo Fisiológico/instrumentación , Temperatura Corporal/fisiología
16.
Med Sci Sports Exerc ; 56(6): 1140-1150, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38233977

RESUMEN

PURPOSE: Muscle mechanics is paramount in our understanding of motor performance. However, little is known regarding the sensitivity of fascicle dynamics and connective tissues stiffness to exercise duration and ambient temperature during running, both increasing muscle temperature. This study aimed to determine gastrocnemius medialis (GM) fascicle dynamics in vivo during running in temperate and hot conditions, as well as muscle-tendon unit responses. METHODS: Using ultrafast ultrasound, 15 participants (8 men, 7 women; 26 ± 3 yr) were tested before, during (2 and 40 min), and after a running task (40 min at 10 km·h -1 ) in temperate (TEMP; ~23°C) and hot (HOT: ~38°C) conditions. RESULTS: Although core, skin temperatures, and heart rate increased from the beginning to the end of the exercise and in a larger extent in HOT than TEMP ( P < 0.001), the physiological stress elicited did not alter running temporal parameters and GM fascicle operating lengths, with similar behavior of the fascicles on their force-length relationship, over time (2 vs 40 min) or across condition (TEMP vs HOT; P ≥ 0.248). Maximal voluntary force production did not reported statistical changes after exercise ( P = 0.060), and the connective tissues stiffness measured (i.e., passive muscle and stiffness of the series-elastic elements) did not show neither time ( P ≥ 0.281), condition ( P ≥ 0.256) nor time-condition interaction ( P ≥ 0.465) effect. CONCLUSIONS: This study revealed that prolonged running exercise does not alter muscle-tendon unit properties and interplay, which are not influenced by ambient temperature. These findings may rule out potential detrimental effects of heat on muscle properties and encourage further investigations on longer and more intense running exercise.


Asunto(s)
Calor , Músculo Esquelético , Carrera , Ultrasonografía , Humanos , Masculino , Carrera/fisiología , Femenino , Adulto , Músculo Esquelético/fisiología , Músculo Esquelético/diagnóstico por imagen , Frecuencia Cardíaca/fisiología , Tendones/fisiología , Tendones/diagnóstico por imagen , Adulto Joven , Temperatura Cutánea/fisiología , Factores de Tiempo , Temperatura Corporal/fisiología , Tejido Conectivo/fisiología
17.
Eur J Appl Physiol ; 124(5): 1523-1534, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38150009

RESUMEN

PURPOSE: Cold-induced vasodilation (CIVD) is an oscillatory rise in blood flow to glabrous skin that occurs in cold-exposed extremities. Dietary flavanols increase bioavailable nitric oxide, a proposed mediator of CIVD through active vasodilation and/or withdrawal of sympathetic vascular smooth muscle tone. However, no studies have examined the effects of flavanol intake on extremity skin perfusion during cold exposure. We tested the hypothesis that acute and 8-day flavanol supplementation would augment CIVD during single-digit cold water immersion (CWI). METHODS: Eleven healthy adults (24 ± 6 years; 10 M/1F) ingested cocoa flavanols (900 mg/day) or caffeine- and theobromine-matched placebo for 8 days in a double-blind, randomized, crossover design. On Days 1 and 8, CIVD was assessed 2 h post-treatment. Subjects immersed their 3rd finger in warm water (42 °C) for 15 min before CWI (4 °C) for 30 min, during which nail bed and finger pad skin temperature were measured. RESULTS: Flavanol ingestion had no effect on CIVD frequency (Day 1, Flavanol: 3 ± 2 vs. Placebo: 3 ± 2; Day 8, Flavanol: 3 ± 2 vs. Placebo: 3 ± 1) or amplitude (Day 1, Flavanol: 4.3 ± 1.7 vs. Placebo: 4.9 ± 2.6 °C; Day 8, Flavanol: 3.9 ± 1.9 vs. Placebo: 3.9 ± 2.0 °C) in the finger pad following acute or 8-day supplementation (P > 0.05). Furthermore, average, nadir, and apex finger pad temperatures during CWI were not different between treatments on Days 1 or 8 of supplementation (P > 0.05). Similarly, no differences in CIVD parameters were observed in the nail bed following supplementation (P > 0.05). CONCLUSION: These data suggest that cocoa flavanol ingestion does not alter finger CIVD. Clinical Trial Registration Clinicaltrials.gov Identifier: NCT04359082. April 24, 2020.


Asunto(s)
Frío , Suplementos Dietéticos , Vasodilatación , Humanos , Masculino , Femenino , Vasodilatación/efectos de los fármacos , Vasodilatación/fisiología , Adulto , Método Doble Ciego , Adulto Joven , Estudios Cruzados , Temperatura Cutánea/efectos de los fármacos , Temperatura Cutánea/fisiología , Cacao , Flavonoles/farmacología , Flavonoles/administración & dosificación , Piel/irrigación sanguínea , Piel/efectos de los fármacos , Chocolate
18.
Nature ; 614(7949): 725-731, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36755097

RESUMEN

Temperature is a fundamental sensory modality separate from touch, with dedicated receptor channels and primary afferent neurons for cool and warm1-3. Unlike for other modalities, however, the cortical encoding of temperature remains unknown, with very few cortical neurons reported that respond to non-painful temperature, and the presence of a 'thermal cortex' is debated4-8. Here, using widefield and two-photon calcium imaging in the mouse forepaw system, we identify cortical neurons that respond to cooling and/or warming with distinct spatial and temporal response properties. We observed a representation of cool, but not warm, in the primary somatosensory cortex, but cool and warm in the posterior insular cortex (pIC). The representation of thermal information in pIC is robust and somatotopically arranged, and reversible manipulations show a profound impact on thermal perception. Despite being positioned along the same one-dimensional sensory axis, the encoding of cool and that of warm are distinct, both in highly and broadly tuned neurons. Together, our results show that pIC contains the primary cortical representation of skin temperature and may help explain how the thermal system generates sensations of cool and warm.


Asunto(s)
Corteza Insular , Neuronas , Temperatura Cutánea , Corteza Somatosensorial , Animales , Ratones , Frío , Neuronas/fisiología , Corteza Somatosensorial/citología , Corteza Somatosensorial/fisiología , Percepción del Tacto/fisiología , Calor , Temperatura Cutánea/fisiología , Análisis Espacio-Temporal , Corteza Insular/citología , Corteza Insular/fisiología
19.
J Therm Biol ; 104: 103174, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35180960

RESUMEN

PURPOSE: This study investigated the influence of whole body cooling on local thermal sensitivity to warm (40°C) and cold (20°C) stimuli in 10 young (age: 24 ± 2 yrs) and 10 older males (age: 69 ± 4 yrs). METHODS: Local warm and cold sensitivity was assessed at eight body regions using a 25 cm2 pressure controlled thermal probe after 40 min of whole body exposure to a thermoneutral (NEUT: 25°C/40% RH) and a cold (COLD: 12°C/50% RH) environment. Gastrointestinal temperature (Tgi), mean and local skin temperature, heart rate, whole body thermal sensation and comfort, and skin blood flow were also measured. RESULTS: Whole body cooling blunted local cold sensitivity but warm sensitivity was maintained in both age groups. Furthermore, a significant age-related decline (from young to older group) in sensitivity to a warm stimulus was observed in both NEUT and COLD conditions. Older males also had a greater ΔTgi compared to the young but had similar thermal sensation and comfort responses. CONCLUSION: The observed interaction effect of local cold stimulation and whole body cooling may be related to both stimuli triggering similar TRP channels, whereas the lack of interaction between local warm stimuli and whole body cooling may be related to these two stimuli triggering different TRP channels. The findings reiterate the potential thermoregulatory risks (e.g. cold injury and hypothermia) associated with ageing, even with such short exposure times.


Asunto(s)
Envejecimiento/fisiología , Frío , Sensación Térmica/fisiología , Adulto , Anciano , Regulación de la Temperatura Corporal , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Temperatura Cutánea/fisiología , Adulto Joven
20.
J Therm Biol ; 104: 103187, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35180966

RESUMEN

Plyometric training has been used in several sports and fitness programs to improve jumping ability and explosive strength, both in individual and team sports. Eccentric muscle actions, such as those performed during plyometric jumps, induce muscle damage and consequently a rise in skin temperature (Tsk). Thus, the purpose of this study is to assess the response of infrared thermography measurement as an indirect marker of muscle damage after a protocol of plyometric jumps in physically active subjects. Therefore, for the aim of this study ten male subjects with no previous experience in plyometric training participated in the research (age 22.5 ± 3.3 years, weight 71.7 ± 11.0 kg, height 171.1 ± 5.3 cm, and fat mass 15.5 ± 4.7%). To assess the muscle damage, countermovement jump (CMJ), creatine kinase (CK), delayed-onset muscle soreness (DOMS) and infrared thermography (IRT) were measured at 24, 48, and 72 h after plyometric exercise. The acute exercise protocol of plyometric jumps induced muscle damage, as shown by the CK and DOMS (24 and 48 h, p < 0.05) but no statistical difference was shown between the moments analyzed in Tsk (warm zone). Nevertheless, when comparing baseline to 48h, a moderate effect was found in the Tsk (warm zone) for anterior right thigh (ES = 1.1) and posterior left thigh (ES = 0.9) and large effect was found for anterior left thigh (ES = 1.4) and posterior right thigh (ES = 1.3). A moderate effect in the Tsk (warm zone) was found for posterior right and left thigh (ES = 0.9 and ES = 1.1, respectively) when comparing baseline to 72h of IRT. These results suggest that a plyometric jumping session alters CK and DOMS, as well as the thigh's skin temperature in an evident way, bringing up a possible relation with markers of muscle damage.


Asunto(s)
Músculo Esquelético/fisiopatología , Ejercicio Pliométrico , Temperatura Cutánea/fisiología , Termografía , Adulto , Biomarcadores/análisis , Creatina Quinasa/sangre , Humanos , Rayos Infrarrojos , Extremidad Inferior/fisiología , Masculino , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/lesiones , Mialgia/etiología , Mialgia/fisiopatología , Adulto Joven
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