scholarly journals A fan-attached jacket worn in an environment exceeding body temperature suppresses an increase in core temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kahori Hashimoto ◽  
Seichi Horie ◽  
Chikage Nagano ◽  
Hiroyuki Hibino ◽  
Kimiyo Mori ◽  
...  
Keyword(s):  
Body Temperature ◽  
Relative Humidity ◽  
Core Temperature ◽  
Heat Dissipation ◽  
Ambient Air ◽  
Bicycle Ergometer ◽  
Japanese Men ◽  
Hot Air ◽  
Subjective Evaluations ◽  
Humidity Environment

AbstractWe examined whether blowing hot air above body temperature under work clothing may suppress core temperature. Nine Japanese men engaged in two 30-min bicycle ergometer sessions at a workload of 40% VO2max at 40 °C and 50% relative humidity. The experiment was conducted without wearing any cooling apparatus (CON), wearing a cooling vest that circulated 10.0 °C water (VEST), and wearing a fan-attached jacket that transferred ambient air underneath the jacket at a rate of 30 L/s (FAN). The VEST and FAN conditions suppressed the increases of rectal temperature (CON, VEST, FAN; 38.01 ± 0.19 °C, 37.72 ± 0.12 °C (p = 0.0076), 37.54 ± 0.19 °C (p = 0.0023), respectively), esophageal temperature (38.22 ± 0.30 °C, 37.55 ± 0.18 °C (p = 0.0039), 37.54 ± 0.21 °C (p = 0.0039), respectively), and heart rate (157.3 ± 9.8 bpm, 136.9 ± 8.9 bpm, (p = 0.0042), 137.5 ± 6.5 bpm (p = 0.0023), respectively). Two conditions also reduced the estimated amount of sweating and improved various subjective evaluations. Even in the 40 °C and 50% relative humidity environment, we may recommend wearing a fan-attached jacket because the heat dissipation through evaporation exceeded the heat convection from the hot ambient air.

scholarly journals Is Oral Temperature an Accurate Measurement of Deep Body Temperature? A Systematic Review

2011 ◽  
Vol 46 (5) ◽  
pp. 566-573 ◽  
Author(s):  
Stephanie M. Mazerolle ◽  
Matthew S. Ganio ◽  
Douglas J. Casa ◽  
Jakob Vingren ◽  
Jennifer Klau
Keyword(s):  
Body Temperature ◽  
Key Words ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Ambient Air ◽  
Controlled Vocabulary ◽  
Cochrane Library ◽  
Original Research ◽  
Oral Temperature ◽  
Core Body

Context: Oral temperature might not be a valid method to assess core body temperature. However, many clinicians, including athletic trainers, use it rather than criterion standard methods, such as rectal thermometry. Objective: To critically evaluate original research addressing the validity of using oral temperature as a measurement of core body temperature during periods of rest and changing core temperature. Data Sources: In July 2010, we searched the electronic databases PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTDiscus, Academic Search Premier, and the Cochrane Library for the following concepts: core body temperature, oral, and thermometers. Controlled vocabulary was used, when available, as well as key words and variations of those key words. The search was limited to articles focusing on temperature readings and studies involving human participants. Data Synthesis: Original research was reviewed using the Physiotherapy Evidence Database (PEDro). Sixteen studies met the inclusion criteria and subsequently were evaluated by 2 independent reviewers. All 16 were included in the review because they met the minimal PEDro score of 4 points (of 10 possible points), with all but 2 scoring 5 points. A critical review of these studies indicated a disparity between oral and criterion standard temperature methods (eg, rectal and esophageal) specifically as the temperature increased. The difference was −0.50°C ± 0.31°C at rest and −0.58°C ± 0.75°C during a nonsteady state. Conclusions: Evidence suggests that, regardless of whether the assessment is recorded at rest or during periods of changing core temperature, oral temperature is an unsuitable diagnostic tool for determining body temperature because many measures demonstrated differences greater than the predetermined validity threshold of 0.27°C (0.5°F). In addition, the differences were greatest at the highest rectal temperatures. Oral temperature cannot accurately reflect core body temperature, probably because it is influenced by factors such as ambient air temperature, probe placement, and ingestion of fluids. Any reliance on oral temperature in an emergency, such as exertional heat stroke, might grossly underestimate temperature and delay proper diagnosis and treatment.

Influence of training on sweating responses during submaximal exercise in horses

2000 ◽  
Vol 89 (6) ◽  
pp. 2463-2471 ◽  
Author(s):  
L. J. McCutcheon ◽  
R. J. Geor
Keyword(s):  
Relative Humidity ◽  
Core Temperature ◽  
Heat Dissipation ◽  
Fold Increase ◽  
Moderate Intensity ◽  
Dry Conditions ◽  
Fluid Losses ◽  
Sweating Threshold ◽  
Intensity Training ◽  
Cool Conditions

Sweating responses were examined in five horses during a standardized exercise test (SET) in hot conditions (32–34°C, 45–55% relative humidity) during 8 wk of exercise training (5 days/wk) in moderate conditions (19–21°C, 45–55% relative humidity). SETs consisting of 7 km at 50% maximal O2 consumption, determined 1 wk before training day (TD) 0, were completed on a treadmill set at a 6° incline on TD0, 14, 28, 42, and 56. Mean maximal O2consumption, measured 2 days before each SET, increased 19% [TD0 to 42: 135 ± 5 (SE) to 161 ± 4 ml · kg−1 · min−1]. Peak sweating rate (SR) during exercise increased on TD14, 28, 42, and 56 compared with TD0, whereas SRs and sweat losses in recovery decreased by TD28. By TD56, end-exercise rectal and pulmonary artery temperature decreased by 0.9 ± 0.1 and 1.2 ± 0.1°C, respectively, and mean change in body mass during the SET decreased by 23% (TD0: 10.1 ± 0.9; TD56: 7.7 ± 0.3 kg). Sweat Na+concentration during exercise decreased, whereas sweat K+concentration increased, and values for Cl− concentration in sweat were unchanged. Moderate-intensity training in cool conditions resulted in a 1.6-fold increase in sweating sensitivity evident by 4 wk and a 0.7 ± 0.1°C decrease in sweating threshold after 8 wk during exercise in hot, dry conditions. Altered sweating responses contributed to improved heat dissipation during exercise and a lower end-exercise core temperature. Despite higher SRs for a given core temperature during exercise, decreases in recovery SRs result in an overall reduction in sweat fluid losses but no change in total sweat ion losses after training.

The Influence of Hot Air Environment and Humidity towards the Performance of Folding Endurance for Polypropylene Hinges

2013 ◽  
Vol 315 ◽  
pp. 572-576
Author(s):  
Mohd Hilmi Othman ◽  
Nor Mazlana Main ◽  
Sulaiman Hasan ◽  
Mohd Izuan Kamaruzamend
Keyword(s):  
Relative Humidity ◽  
Signal To Noise Ratio ◽  
Influential Factor ◽  
Motor Speed ◽  
Signal To Noise ◽  
Hot Air ◽  
Folding Endurance ◽  
Noise Ratio ◽  
Breaking Time ◽  
Humidity Environment

Folding endurance is very important in terms of the indication for durability and performance of plastics and papers. The objective of this research is to study the performance of polypropylene hinges with the influence hot air in the fabricated chamber and high humidity condition. The performance of this sample was analysed by using folding endurance tester with hot air chamber, adopting the Design of Experiment L9 (34) Taguchi Method for the selected factors which are temperature, relative humidity, breaking time and motor speed. All of these factors were selected with a constant force. Based on the findings, the best combination of parameters which signify the performance of folding endurance test in humidity environment is 70°C for temperature, 60 N for relative humidity, 2 days of breaking time and 850 rpm for motor speed. As for hot air environment, the best setting is 70°C for temperature, 55 N for relative humidity, 3 days of breaking time and 700 rpm for motor speed. For Signal to Noise ratio, the result showed that the temperature was the most influential factor for humidity effects and hot air environment, whereby the Signal to Noise ratio value obtained for the humidity and hot air environment are 129.5 dBi and 130.5 dBi respectively. The conclusion of this research is the polypropylene hinges have performed better with hot air environment as compared with higher humidity environment condition.

Effect of cold air inhalation on core temperature in exercising subjects under heat stress

1988 ◽  
Vol 64 (6) ◽  
pp. 2381-2387 ◽  
Author(s):  
N. Geladas ◽  
E. W. Banister
Keyword(s):  
Heat Stress ◽  
Skin Temperature ◽  
Core Temperature ◽  
Random Sequence ◽  
Ambient Air ◽  
Fluid Loss ◽  
Physical Conditioning ◽  
Upper Airways ◽  
Cold Air ◽  
Hot Air

Whether increasing respiratory heat loss (RHL) during exercise under heat stress can contain elevation of rectal temperature (Tre) was examined. Eight men cycled twice at 45–50% their maximum work rate until exhaustion at ambient temperature and relative humidity of 38 degrees C and 90–95%, respectively. They inspired either cold (3.6 degrees C) or ambient air in random sequence. When subjects breathed cold air during 23 min of exercise, a ninefold increase in RHL was observed vs. similar work during hot air inhalation (32.81 vs. 3.46 W). Respiratory frequency (f) and rate of rise in Tre decreased significantly (P less than or equal to 0.004 and P less than or equal to 0.002, respectively). The rise in skin temperature in each inhalant gas condition was accompanied by a parallel almost equal increase in core temperature above basal (delta Tre) for equivalent gains in skin temperature. The increase in tidal volume and decreased f in the cold condition allowed more effective physical conditioning of cold inspirate gas in the upper airways and aided RHL. Cold air inhalation also produced a significant (P less than or equal to 0.05) decrease in heart rate vs. hot air inhalation in the final stages of exercise. Insignificant changes in O2 consumption and total body fluid loss were found. These data show that cold air inhalation during exercise diminishes elevation of Tre and suggest that both the intensity and duration of work can thus be extended. The importance of the physical exchange of heat energy and any physiological mechanisms induced by the cold inspirate in producing the changes is undetermined.

Contactless Core-Temperature Monitoring by Infrared Thermal Sensor using Mean Absolute Error Analysis

2020 ◽  
Vol 15 ◽  
Author(s):  
Fahad Layth Malallah ◽  
Baraa T. Shareef ◽  
Mustafah Ghanem Saeed ◽  
Khaled N. Yasen
Keyword(s):  
Body Temperature ◽  
Embedded System ◽  
Core Temperature ◽  
Integrated Circuit ◽  
Mean Absolute Error ◽  
Absolute Error ◽  
Thermal Sensor ◽  
Human Face ◽  
Body Contact ◽  
Arduino Microcontroller

Aims: Normally, the temperature increase of individuals leads to the possibility of getting a type of disease, which might be risky to other people such as coronavirus. Traditional techniques for tracking core-temperature require body contact either by oral, rectum, axillary, or tympanic, which are unfortunately considered intrusive in nature as well as causes of contagion. Therefore, sensing human core-temperature non-intrusively and remotely is the objective of this research. Background: Nowadays, increasing level of medical sectors is a necessary targets for the research operations, especially with the development of the integrated circuit, sensors and cameras that made the normal life easier. Methods: The solution is by proposing an embedded system consisting of the Arduino microcontroller, which is trained with a model of Mean Absolute Error (MAE) analysis for predicting Contactless Core-Temperature (CCT), which is the real body temperature. Results: The Arduino is connected to an Infrared-Thermal sensor named MLX90614 as input signal, and connected to the LCD to display the CCT. To evaluate the proposed system, experiments are conducted by participating 31-subject sensing contactless temperature from the three face sub-regions: forehead, nose, and cheek. Conclusion: Experimental results approved that CCT can be measured remotely depending on the human face, in which the forehead region is better to be dependent, rather than nose and cheek regions for CCT measurement due to the smallest

scholarly journals A novel mouse model of heatstroke accounting for ambient temperature and relative humidity

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kazuyuki Miyamoto ◽  
Keisuke Suzuki ◽  
Hirokazu Ohtaki ◽  
Motoyasu Nakamura ◽  
Hiroki Yamaga ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Organ Damage ◽  
Core Body ◽  
The Impact ◽  
Treatment Water

Abstract Background Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure. Methods Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS. Results The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage. Conclusions We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.

Influence of Non-Equilibrium Fluid Properties During Fogging on Intake Duct and Compressor Characteristics

2017 ◽  
Author(s):  
Christoph Günther ◽  
Franz Joos
Keyword(s):  
Relative Humidity ◽  
Gas Turbine ◽  
Thermophysical Properties ◽  
Ambient Air ◽  
Compressor Stage ◽  
Compression Process ◽  
Fluid Properties ◽  
Temperature And Pressure ◽  
Gas Turbine Compressor ◽  
Non Equilibrium

This study reports on numerically calculated thermophysical properties of air passing through a gas turbine compressor after passage through an intake duct affected by wet compression. Case of reference is unaffected ambient air (referenced to as dry scenario) passing through intake duct and compressor. Furthermore, ambient air cooled down by (overspray) fogging (referenced to as wet scenarios) was considered. Acceleration at the end of intake duct causing reduction of static temperature and pressure results in supersaturated fluid properties at inlet to gas turbine compressor. These supersaturated fluid properties are non-equilibrium with saturation level above relative humidity of φ = 1. Entrance of supersaturated fluid into gas turbine compressor can result in condensation within first compressor stage. At the same time delayed impact of evaporative cooling influences compression process.

Desaturation of exhaled air in camels

1981 ◽  
Vol 211 (1184) ◽  
pp. 305-319 ◽  
Keyword(s):  
Drinking Water ◽  
Heat Exchange ◽  
Body Temperature ◽  
Water Vapour ◽  
Mechanical Model ◽  
Ambient Air ◽  
Body Core Temperature ◽  
Hygroscopic Properties ◽  
Exhaled Air ◽  
Body Core

We have found that camels can reduce the water loss due to evaporation from the respiratory tract in two ways: (1) by decreasing the temperature of the exhaled air and (2) by removal of water vapour from this air, resulting in the exhalation of air at less than 100% relative humidity (r. h.). Camels were kept under desert conditions and deprived of drinking water. In the daytime the exhaled air was at or near body core temperature, while in the cooler night exhaled air was at or near ambient air temperature. In the daytime the exhaled air was fully saturated, but at night its humidity might fall to approximately 75% r. h. The combination of cooling and desaturation can provide a saving of water of 60% relative to exhalation of saturated air at body temperature. The mechanism responsible for cooling of the exhaled air is a simple heat exchange between the respiratory air and the surfaces of the nasal passageways. On inhalation these surfaces are cooled by the air passing over them, and on exhalation heat from the exhaled air is given off to these cooler surfaces. The mechanism responsible for desaturation of the air appears to depend on the hygroscopic properties of the nasal surfaces when the camel is dehydrated. The surfaces give off water vapour during inhalation and take up water from the respiratory air during exhalation. We have used a simple mechanical model to demonstrate the effectiveness of this mechanism.

scholarly journals Temperature Monitoring and Perioperative Thermoregulation

2008 ◽  
Vol 109 (2) ◽  
pp. 318-338 ◽  
Author(s):  
Daniel I. Sessler ◽  
David S. Warner ◽  
Mark A. Warner
Keyword(s):  
Body Temperature ◽  
General Anesthesia ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Neuraxial Anesthesia ◽  
General Anesthetics ◽  
The Core ◽  
Core Body ◽  
Dose Dependent ◽  
Body Heat

Most clinically available thermometers accurately report the temperature of whatever tissue is being measured. The difficulty is that no reliably core-temperature-measuring sites are completely noninvasive and easy to use-especially in patients not undergoing general anesthesia. Nonetheless, temperature can be reliably measured in most patients. Body temperature should be measured in patients undergoing general anesthesia exceeding 30 min in duration and in patients undergoing major operations during neuraxial anesthesia. Core body temperature is normally tightly regulated. All general anesthetics produce a profound dose-dependent reduction in the core temperature, triggering cold defenses, including arteriovenous shunt vasoconstriction and shivering. Anesthetic-induced impairment of normal thermoregulatory control, with the resulting core-to-peripheral redistribution of body heat, is the primary cause of hypothermia in most patients. Neuraxial anesthesia also impairs thermoregulatory control, although to a lesser extent than does general anesthesia. Prolonged epidural analgesia is associated with hyperthermia whose cause remains unknown.

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