Day–night variation of thermoregulatory responses of heifers exposed to high environmental temperatures

1997 ◽  
Vol 129 (2) ◽  
pp. 199-204 ◽  
Author(s):  
C. M. MUNDIA ◽  
S. YAMAMOTO
Keyword(s):  
Skin Temperature ◽  
Respiration Rate ◽  
Heat Balance ◽  
Thermal Sensitivity ◽  
Skin Surface ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Rate Of Increase ◽  
Vaginal Temperature ◽  
Environmental Temperatures

In order to assess relative thermal sensitivity between the day and the night, vaginal temperature (Tv), heat production (HP), heart rate (HR), respiration rate (RR), skin surface temperatures (from which mean skin temperature (Ts) was calculated) and standing time were measured at environmental temperatures (Te) of 23, 28, 33 and 38°C during the day (11.00–15.00 h) and during the night (23.00–03.00 h) using four Holstein heifers. Both Tv and mean body temperature (Tb) were greater during the night than during the day, increased with increased Te, and the rate of increase of both Tv and Tb with increased Te was greater during the night (P<0·05). Estimated mean HP was similar during the night and during the day, and HP did not increase with increased Te. Respiration rate was greater but not significantly different at night compared to during the day, and increased with increased Te. Mean skin temperature was similar between day and night, and increased with increased Te. The amount of time engaged in standing activity was greater but not significantly different during the night than during the day and standing activity increased with increased Te. The results suggest that thermal sensitivity is lower during the night than during the day, and consequently the greater night responses of Tv and Tb, over day responses, are a requirement for the maintenance of heat balance.

scholarly journals Effect of food intake on the ventilatory response to increasing core temperature during exercise

2019 ◽  
Vol 44 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Keiji Hayashi ◽  
Nozomi Ito ◽  
Yoko Ichikawa ◽  
Yuichi Suzuki
Keyword(s):  
Food Intake ◽  
Body Temperature ◽  
Skin Temperature ◽  
Core Temperature ◽  
Mean Skin Temperature ◽  
Carbon Dioxide Elimination ◽  
Transient Effect ◽  
Mean Body Temperature ◽  
Ventilatory Parameters ◽  
Effect Of Food

Food intake increases metabolism and body temperature, which may in turn influence ventilatory responses. Our aim was to assess the effect of food intake on ventilatory sensitivity to rising core temperature during exercise. Nine healthy male subjects exercised on a cycle ergometer at 50% of peak oxygen uptake in sessions with and without prior food intake. Ventilatory sensitivity to rising core temperature was defined by the slopes of regression lines relating ventilatory parameters to core temperature. Mean skin temperature, mean body temperature (calculated from esophageal temperature and mean skin temperature), oxygen uptake, carbon dioxide elimination, minute ventilation, alveolar ventilation, and tidal volume (VT) were all significantly higher at baseline in sessions with food intake than without food intake. During exercise, esophageal temperature, mean skin temperature, mean body temperature, carbon dioxide elimination, and end-tidal CO2 pressure were all significantly higher in sessions with food intake than without it. By contrast, ventilatory parameters did not differ between sessions with and without food intake, with the exception of VT during the first 5 min of exercise. The ventilatory sensitivities to rising core temperature also did not differ, with the exception of an early transient effect on VT. Food intake increases body temperature before and during exercise. Other than during the first 5 min of exercise, food intake does not affect ventilatory parameters during exercise, despite elevation of both body temperature and metabolism. Thus, with the exception of an early transient effect on VT, ventilatory sensitivity to rising core temperature is not affected by food intake.

Effect of Undergarments on Micro-Environment under Anti-Static Dust-Free Clothing

2013 ◽  
Vol 796 ◽  
pp. 630-633 ◽  
Author(s):  
Ying Liu ◽  
Han Yu Wu ◽  
Yu Ping Li ◽  
Xiao Qun Dai
Keyword(s):  
Relative Humidity ◽  
Skin Temperature ◽  
Protective Clothing ◽  
Skin Surface ◽  
Woven Fabric ◽  
Mean Skin Temperature ◽  
Climate Chamber ◽  
Knitted Fabrics

In this study, the effect of different undergarments on micro-climate environment under anti-static dust-free clothing was investigated. Five male undergraduates participated in wear trials conducted in a climate chamber of 24 ± 1°C and 60 ± 5%RH, three undergarments of different materials were worn under an antistatic dust-free overall respectively. While subjects doing mild exercise, the temperature and relative humidity under the undergarment was measured at chest, and the skin temperature at arm, chest, thigh and calf were measured. It was found that undergarment made of plain woven fabric was the best to keep the relative humidity on skin surface low and mean skin temperature stable during mild exercise among three undergarments of different materials. It was demonstrated that hydrophilic fiber might not the best material of undergarment for protective clothing, knitted fabrics which have more volume to hold water might not be good either. It was showed that materials absorb water and moisture and quick dry is suitable to undergarment for protective clothing.

Estimating changes in mean body temperature for humans during exercise using core and skin temperatures is inaccurate even with a correction factor

2007 ◽  
Vol 103 (2) ◽  
pp. 443-451 ◽  
Author(s):  
Ollie Jay ◽  
Francis D. Reardon ◽  
Paul Webb ◽  
Michel B. DuCharme ◽  
Tim Ramsay ◽  
...  
Keyword(s):  
Body Temperature ◽  
Skin Temperature ◽  
Correction Factor ◽  
Estimation Error ◽  
Compartment Model ◽  
Traditional Model ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Two Compartment Model ◽  
Adjusted Model

Changes in mean body temperature (ΔT̄b) estimated by the traditional two-compartment model of “core” and “shell” temperatures and an adjusted two-compartment model incorporating a correction factor were compared with values derived by whole body calorimetry. Sixty participants (31 men, 29 women) cycled at 40% of peak O2 consumption for 60 or 90 min in the Snellen calorimeter at 24 or 30°C. The core compartment was represented by esophageal, rectal (Tre), and aural canal temperature, and the shell compartment was represented by a 12-point mean skin temperature (T̄sk). Using Tre and conventional core-to-shell weightings ( X) of 0.66, 0.79, and 0.90, mean ΔT̄b estimation error (with 95% confidence interval limits in parentheses) for the traditional model was −95.2% (−83.0, −107.3) to −76.6% (−72.8, −80.5) after 10 min and −47.2% (−40.9, −53.5) to −22.6% (−14.5, −30.7) after 90 min. Using Tre, X = 0.80, and a correction factor ( X0) of 0.40, mean ΔT̄b estimation error for the adjusted model was +9.5% (+16.9, +2.1) to −0.3% (+11.9, −12.5) after 10 min and +15.0% (+27.2, +2.8) to −13.7% (−4.2, −23.3) after 90 min. Quadratic analyses of calorimetry ΔT̄b data was subsequently used to derive best-fitting values of X for both models and X0 for the adjusted model for each measure of core temperature. The most accurate model at any time point or condition only accounted for 20% of the variation observed in ΔT̄b for the traditional model and 56% for the adjusted model. In conclusion, throughout exercise the estimation of ΔT̄b using any measure of core temperature together with mean skin temperature irrespective of weighting is inaccurate even with a correction factor customized for the specific conditions.

Safety and health risks for workers exposed to cold thermal environments: A frozen food processing industry perspective

Work ◽  
2021 ◽  
pp. 1-11
Author(s):  
Tomi Zlatar ◽  
Béda Barkokébas Junior ◽  
Laura Martins Bezerra ◽  
Margarida Maria Araujo Brito ◽  
José Torres Costa ◽  
...  
Keyword(s):  
Skin Temperature ◽  
Food Industry ◽  
Thermal Sensation ◽  
Cold Work ◽  
Health And Safety ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Frozen Food ◽  
Thermal Environments ◽  
Fresh Food

BACKGROUND: Environmental temperatures in the fresh food industry vary from 0°C to 10°C, and go below -20°C for the frozen food industry, representing risk for the health and safety of workers involved. OBJECTIVE: The aim of this work was to evaluate the cold thermal stress risks for workers working in a frozen food industry. METHODS: A total of 27 acclimatized workers (13 male and 14 female) participated in a study which was conducted during 11 working days. The thermal sensation questionnaire and the cold work health questionnaire (CWHQ) were applied to all participants. Additionally, 4 workers were chosen to be fully monitored with a thermometer telemetry capsule for measuring the intra-abdominal temperature and 8 skin temperature sensors. RESULTS: The lowest recorded hand temperature was 14.09°C, lowest forehead 18.55°C, mean skin temperature had variations of 1.10 to 3.20°C along the working period. Highest and most frequent fluctuations were found in the hand and forehead skin temperatures, small changes were found in mean skin temperature. CONCLUSIONS: Answers to the CWHQ increase concern on clinical forms of “a frigore”, and in two cases the mean body temperature decreased below 35.0°C, which is defined in the current literature as a mild form of hypothermia.

Calculation of mean body temperature

1968 ◽  
Vol 46 (1) ◽  
pp. 15-17 ◽  
Author(s):  
S. D. Livingstone
Keyword(s):  
Skin Temperature ◽  
Initial Period ◽  
Young Male ◽  
Heat Losses ◽  
The Body ◽  
Body Temperatures ◽  
Mean Body Temperature ◽  
Constant Coefficients ◽  
Environmental Temperatures ◽  
Male Subjects

Four young male subjects were exposed for 1 h to environmental temperatures of 8.5 °C, 14.0 °C, and 20.0 °C while lying on a rope mesh cot. During exposure they wore swimming trunks only. Heat production, skin temperature at seven locations, and rectal temperature were measured. Mean body temperatures (MBT) and heat debts were calculated from Burton's equations and also from equations determining radiative, convective, and evaporative heat losses. It was found that a linear equation with constant coefficients, such as Burton's, for measuring MBT does not allow for the fact that in the non-steady state the body continues to lose heat even though the skin temperature is relatively constant. During the initial period of cold exposure the coefficient of skin temperature when calculating MBT should be much smaller than at later stages in the cooling.

Skin-surface cooling elicits peripheral and visceral vasoconstriction in humans

2007 ◽  
Vol 103 (4) ◽  
pp. 1257-1262 ◽  
Author(s):  
Thad E. Wilson ◽  
Charity L. Sauder ◽  
Matthew L. Kearney ◽  
Nathan T. Kuipers ◽  
Urs A. Leuenberger ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Skin Temperature ◽  
Pressor Response ◽  
Skin Surface ◽  
Blood Velocity ◽  
Mean Skin Temperature ◽  
Surface Cooling ◽  
Vascular Conductance

Skin-surface cooling elicits a pronounced systemic pressor response, which has previously been reported to be associated with peripheral vasoconstriction and may not fully account for the decrease in systemic vascular conductance. To test the hypothesis that whole body skin-surface cooling would also induce renal and splanchnic vasoconstriction, 14 supine subjects performed 26 skin-surface cooling trials (15–18°C water perfused through a tube-lined suit for 20 min). Oral and mean skin temperature, heart rate, stroke volume (Doppler ultrasound), mean arterial blood pressure (MAP), cutaneous blood velocity (laser-Doppler), and mean blood velocity of the brachial, celiac, renal, and superior mesenteric arteries (Doppler ultrasound) were measured during normothermia and skin-surface cooling. Cardiac output (heart rate·stroke volume) and indexes of vascular conductance (flux or blood velocity/MAP) were calculated. Skin-surface cooling increased MAP ( n = 26; 78 ± 5 to 88 ± 5 mmHg; mean ± SD) and decreased mean skin temperature ( n = 26; 33.7 ± 0.7 to 27.5 ± 1.2°C) and cutaneous ( n = 12; 0.93 ± 0.68 to 0.36 ± 0.20 flux/mmHg), brachial ( n = 10; 32 ± 15 to 20 ± 12), celiac ( n = 8; 85 ± 22 to 73 ± 22 cm·s−1·mmHg−1), superior mesenteric ( n = 8; 55 ± 16 to 48 ± 10 cm·s−1·mmHg−1), and renal ( n = 8; 74 ± 26 to 64 ± 20 cm·s−1·mmHg−1; all P < 0.05) vascular conductance, without altering oral temperature, cardiac output, heart rate, or stroke volume. These data identify decreases in vascular conductance of skin and of brachial, celiac, superior mesenteric, and renal arteries. Thus it appears that vasoconstriction in both peripheral and visceral arteries contributes importantly to the pressor response produced during skin-surface cooling in humans.

Regional surface areas of spontaneously hypertensive and Wistar-Kyoto rats

1987 ◽  
Vol 62 (2) ◽  
pp. 752-755 ◽  
Author(s):  
W. A. Lyzak ◽  
W. S. Hunter
Keyword(s):  
Skin Temperature ◽  
Surface Area ◽  
Skin Surface ◽  
Total Surface Area ◽  
Mean Skin Temperature ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Surface Areas ◽  
Dental Impression ◽  
Wistar Kyoto

Regional skin surface area and region-specific weighting factors for calculating mean skin temperature have not been determined for the rat. Therefore, measurements were made of total skin surface area segmented into five regions of 12 spontaneously hypertensive (SHR) and 12 normotensive Wistar-Kyoto (WKY) rats. SHR's were selected because chronically elevated core temperature and reduced ability of SHR's to withstand heat stress make them of interest for thermoregulatory studies. Area was determined by coating the skin with rubber base dental impression material, then measuring the area of the coating. The relationship between total skin surface area and mass of SHR's was not different from that of WKY's and is described by the equation SA = 8.62 M0.67. However, the ears of SHR's had larger surface area and their tails smaller surface area than those of WKY's. For the combined groups, the proportion of total surface area of the regions was as follows: ears, 0.022; front feet, 0.017; hind feet, 0.040; tail, 0.100; central skin, 0.826. These data provide a basis for calculating skin surface area, mean skin temperature, and related values for SHR and WKY rats.

Thermo-physiological comfort of business clothing incorporating phase change materials in a cold environment

2018 ◽  
Vol 30 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Damjana Celcar
Keyword(s):  
Skin Temperature ◽  
Environmental Conditions ◽  
Phase Change Materials ◽  
Physiological Parameters ◽  
Cold Environment ◽  
Mean Skin Temperature ◽  
Content Type ◽  
Business Clothing ◽  
Study Participants ◽  
Environmental Temperatures

Purpose The purpose of this paper is to investigate the thermo-physiological comfort of male business garments made of common textiles, as well as business clothing that contains phase change materials (PCMs) as a lining or outerwear material. In view of the fact that people wear business clothing throughout the whole day in different environmental conditions, this study investigate the effect of PCMs incorporated in male business clothing systems on the thermo-physiological comfort of the wearer under different cold environmental conditions. Design/methodology/approach The influence of particular business garments on the thermo-physiological comfort of the wearer during different physical activities and cold environmental temperatures was determined experimentally with the help of study participants, as a change of two physiological parameters: mean skin temperature and heart rate. A questionnaire and an assessment scale were also used in order to evaluate the wearer’s subjective feeling of comfort. In this investigation, all tests with study participants were performed under artificially created environmental conditions in a climate chamber at different cold environmental temperatures ranging from 10°C to −5°C with increments of 5°C, and different physical activities that simulate as closely as possible real life activities such as sitting and walking. Findings The results of the performed research work show that PCMs provide a small temporary thermal effect that is reflected in small increases or decreases in mean skin temperature during changes in activity. Furthermore, it was concluded that the small effect of PCMs in business clothing systems on the thermo-physiological comfort of the wearer in a cold environment, which is shown as a change of mean skin temperature when subjects walk on a treadmill and subsequently move to a sitting position, should not be ignored in a cold environment where low skin temperatures were measured. Practical implications The results of this study demonstrate that the physiological parameters of thermo-physiological comfort, in combination with subjective evaluation, provide valuable information for textile and clothing manufactures as well as scientists and engineers involved in the design and development of new products with thermal comfort as a quality criterion. Originality/value The investigation shows that different environmental conditions, activity levels and thermal properties of clothing systems have a considerable impact on the physiological parameters of the subjects and subjective assessment of thermal comfort in a cold environment, and that PCMs incorporated in business clothing systems provide a small temporary thermal effect that is reflected in small increases or decreases in mean skin temperature during changes in activity, such as when subjects walk on a treadmill and subsequently move to a sitting position.

Thermoregulatory responses to cold water at different times of day

1999 ◽  
Vol 87 (1) ◽  
pp. 243-246 ◽  
Author(s):  
John W. Castellani ◽  
Andrew J. Young ◽  
James E. Kain ◽  
Michael N. Sawka
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Early Morning ◽  
Cold Water Immersion ◽  
Time Of Day ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Metabolic Heat ◽  
Body Temperature Change ◽  
The Mean

This study examined how time of day affects thermoregulation during cold-water immersion (CWI). It was hypothesized that the shivering and vasoconstrictor responses to CWI would differ at 0700 vs. 1500 because of lower initial core temperatures (Tcore) at 0700. Nine men were immersed (20°C, 2 h) at 0700 and 1500 on 2 days. No differences ( P > 0.05) between times were observed for metabolic heat production (M˙, 150 W ⋅ m−2), heat flow (250 W ⋅ m−2), mean skin temperature (T sk, 21°C), and the mean body temperature-change in M˙(ΔM˙) relationship. Rectal temperature (Tre) was higher ( P < 0.05) before (Δ = 0.4°C) and throughout CWI during 1500. The change in Tre was greater ( P < 0.05) at 1500 (−1.4°C) vs. 0700 (−1.2°C), likely because of the higher Tre-T skgradient (0.3°C) at 1500. These data indicate that shivering and vasoconstriction are not affected by time of day. These observations raise the possibility that CWI may increase the risk of hypothermia in the early morning because of a lower initial Tcore.

INCREASING MEAN SKIN TEMPERATURE LINEARLY REDUCES THE VASOCONSTRICTION AND SHIVERING THRESHOLDS IN HUMANS

1994 ◽  
Vol 81 (SUPPLEMENT) ◽  
pp. A252
Author(s):  
C. Cheng ◽  
T. Matsukawa ◽  
A. Kurz ◽  
D. I. Sessler ◽  
B. Merrifield
Keyword(s):  
Skin Temperature ◽  
Mean Skin Temperature
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