共查询到20条相似文献,搜索用时 15 毫秒
1.
Waterhouse J Edwards B Bedford P Hughes A Robinson K Nevill A Weinert D Reilly T 《Chronobiology international》2004,21(2):253-275
Eight healthy subjects exercised at 90 watts on a cycle ergometer on four occasions, at times close to the minimum, maximum rate of rise, maximum, and maximum rate of fall of their resting core temperature. The duration of exercise was determined by the time taken for the core (rectal) temperature to reach an equilibrium value. Forearm skin blood flow and temperature were measured regularly during the exercise, as were heart rate and ratings of perceived exertion. Sweat loss was calculated by weighing the subjects nude before and after the exercise. The rise of heart rate was not significantly different at the four times of exercise, though the rating of perceived exertion was greatest at 05:00 h. Resting core temperatures showed a significant circadian rhythm at rest (the timing of which confirmed that exercise was being performed at the required times), but the amplitude of this rhythm was decreased significantly by the exercise. The initial rate of rise of core temperature, and the total rise from the resting to the equilibrium value, were both inversely proportional to resting temperature. The time-course of the rise was accurately described by a negative-exponential model, but this model gave no evidence that the kinetics of the equilibration process depended upon the time of day. The thermoregulatory responses to the rise in core temperature—the amount of total sweat loss and rises in forearm skin blood flow and temperature—differed according to the time of exercise. In general, the responses were significantly greater at 17:00 h compared with 05:00 h, and at 23:00 h compared with 11:00 h. The results accord with predictions made on the basis of previous work by us in which core temperature rhythms have been separated into components due to the endogenous body clock and due to the direct effects of spontaneous activity. The results are discussed in terms of the ecological implications of the differing capabilities of humans to deal with heat loads produced by spontaneous activity or mild exercise at different phases of the circadian rhythm of resting core temperature. 相似文献
2.
N. Kondo Manabu Nakadome Keren Zhang Tomoyuki Shiojiri Manabu Shibasaki Kozo Hirata Atsushi Iwata 《International journal of biometeorology》1997,40(2):99-102
The purpose of this study was to investigate whether there are any effects of skin temperature changes on sweating response
in the first few minutes of mild exercise. Six healthy males performed a bicycle exercise at 100 W (50 rpm) for 30 min under
an ambient temperature of 23° C (40% RH). Esophageal temperature (T
es), mean skin temperature (T–
sk), local skin temperature at the lower left scapula (T
sl), local sweating rate (M.
sw), and cutaneous blood flow by laser-Doppler flowmetry (LDF) were measured continuously. Although T
sl decreased markedly just after the onset of sweating, T–
sk did not change. M.
sw did not increase constantly in the early stages of exercise, and there was a temporary interruption in the increase of M.
sw. This interruption in sweating was affected by the rate of change in T
sl rather than by the absolute value of T
sl, since there was a positive and significant correlation between the time of the interruption in the increase of M.
sw and the rate of decrease in T
sl (y=6.47x+0.04; r=0.86, P<0.05). The results suggest that sweating response in the early stages of exercise may be influenced by changes in local skin
temperature due to evaporative cooling.
Received: 31 August 1995 / Revised: 26 February 1996 / Accepted: 26 July 1996, 相似文献
3.
In this experiment, hand and forearm vasomotor activity was investigated during localised, but stable heating and cooling of the face, hand and thigh, under open-loop (clamped) conditions. It was hypothesised that facial stimulation would provoke the most potent vascular changes. Nine individuals participated in two normothermic trials (mean body temperature clamp: 36.6 °C; water-perfused suit and climate chamber) and two mildly hyperthermic trials (37.9 °C). Localised heating (+5 °C) and cooling (−5 °C) stimuli were applied to equal surface areas of the face, hand and thigh (perfusion patches: 15 min), while contralateral forearm or hand blood flows (venous-occlusion plethysmography) were measured (separate trials). Thermal sensation and discomfort votes were recorded before and during each thermal stimulation. When hyperthermic, local heating induced more sensitive vascular responses, with the combined thermosensitivity of both limb segments averaging 0.011 mL·100 mL−1·min−1·mmHg−1·°C−1, and 0.005 mL·100 mL−1·min−1·mmHg−1·°C−1 during localised cooling (P<0.05). Inter-site comparisons among the stimulated sites yielded minimal evidence of variations in local thermal sensation, and no differences were observed for vascular conductance (P>0.05). Therefore, regional differences in vasomotor and sensory sensitivity appeared not to exist. When combined with previous observations of sudomotor sensitivity, it seems that, during mild heating and cooling, regional representations within the somatosensory cortex may not translate into meaningful differences in thermal sensation or the central integration of thermoafferent signals. It was concluded that inter-site variations in the cutaneous thermosensitivity of these thermolytic effectors have minimal physiological significance over the ranges investigated thus far. 相似文献
4.
Heidi Mai-Lis Andersen Erik Jrgensen Lise Dybkjr Bente Jrgensen 《Applied animal behaviour science》2008,113(1-3):43-56
The aim of the study was to investigate the relationship between the ear skin temperature and the behaviour of pigs. Fifty-four pigs weighing 75 ± 5 kg were used in three replications (18 pigs per replication) and housed in pens (six pigs per pen) in a controlled climate facility. The room temperature was changed by 2 °C from 18 °C down to 10 °C and up again to 22 °C. The ear skin temperature (EST) was continuously recorded and the activity, lying posture, location and contact with pen mates were scored by 12 min scan sampling for 24 h at the set point temperatures 18 °C, 10 °C and 22 °C. A diurnal rhythm in the EST, the posture and the lying behaviour was found. The EST was highest at night and lowest in the afternoon. During night the pigs had more physical contact to pen mates than during day time. For all three set point temperatures the predominant lying position during the night was the fully recumbent position. The room temperature affected the lying behaviour and the EST. With decreasing room temperature the pigs increased their contact to pen mates and fewer pigs were observed lying in the fully recumbent position. The EST decreased with decreasing room temperature, and the range in the EST's at the three set point temperatures was larger during day than night (4 °C versus 2 °C). The results indicate that pigs adjust their behaviour to a higher EST when resting than when they are active, and they use behavioural adjustment (e.g. increased/decreased contact to pen mates) to bring their skin temperature into a preferred interval. 相似文献
5.
Michael J. Price Ian G. Campbell 《European journal of applied physiology and occupational physiology》1997,76(6):552-560
The thermoregulatory responses of ten paraplegic (PA; T3/4-L4) and nine able-bodied (AB) upper body trained athletes were
examined at rest and during prolonged arm-cranking exercise and passive recovery. Exercise was performed for 90 min at 80%
peak heart rate, and at 21.5 (1.7)°C and 47.0 (7.8)% relative humidity on a Monark cycle ergometer (Ergomedic 814E) adapted
for arm exercise. Mean peak oxygen uptake values for the PA and AB athlete groups were 2.12 (0.41) min−1 and 3.19 (0.38) l · min−1, respectively (P<0.05). At rest, there was no difference in aural temperature between groups [36.2 (0.4)°C for both groups]. However, upper
body skin temperatures for the PA athletes were approximately 1.0 °C warmer than for the AB athletes, whereas lower body skin
temperatures were cooler than those for the AB athletes (1.3 °C and 2.7 °C for the thigh and calf, respectively). Upper and
lower body skin temperatures for the AB athletes were similar. During exercise, blood lactate peaked after 15 min of exercise
for both groups [3.33 (1.26) mmol · l−1 and 4.30 (1.03) mmol · l−1 for the PA and AB athletes, respectively, P<0.05] and decreased throughout the remainder of the exercise period. Aural temperature increased by 0.7 (0.5)°C and 0.6 (0.4)°C
for the AB and PA athletes, respectively. Calf skin temperature for the PA athletes increased during exercise by 1.4 (2.8)°C
(P<0.05), whereas a decrease of 0.8 (2.0)°C (P<0.05) was observed for the AB athletes. During the first 20 min of recovery from exercise, the calf skin temperature of the
AB athletes decreased further [−2.6 (1.3)°C; P<0.05]. Weight losses and changes in plasma volume were similar for both groups [0.7 (0.5) kg and 0.7 (0.4) kg; 5.4 (4.9)%
and 9.7 (6.2)% for the PA and AB athletes, respectively]. In conclusion, the results of this study suggest that the PA athletes
exhibit different thermoregulatory responses at rest and during exercise and passive recovery to those of upper body trained
AB athletes. Despite this, during 90 min of arm-crank exercise in a cool environment, the PA athletes appeared to be at no
greater thermal risk than the AB athletes.
Accepted: 7 May 1997 相似文献
6.
Andrey Sagaidachnyi Andrey Fomin Dmitry Usanov Anatoly Skripal 《Computer methods in biomechanics and biomedical engineering》2019,22(12):1009-1019
Monitoring of skin blood flow oscillations related with mechanical activity of vessels is a very useful modality during diagnosis of peripheral hemodynamic disorders. In this study, we developed a new model and technique for real-time conversion of skin temperature into skin blood flow oscillations, and vice versa. The technique is based on the analogy between the thermal properties of the human skin and electrical properties of the special low-pass filter. Analytical and approximated impulse response functions for the low- and high-pass filters are presented. The general algorithm for the reversible conversion of temperature into blood flow is described. The proposed technique was verified using simulated or experimental data of cold stress, deep inspiratory gasp, and post-occlusive reactive hyperaemia tests. The implementation of the described technique will enable to turn a temperature sensor into a blood flow sensor. 相似文献
7.
New technologies afford convenient modalities for skin temperature (TSKIN) measurement, notably involving wireless telemetry and non-contact infrared thermometry. The purpose of this study was to investigate the validity and reliability of skin temperature measurements using a telemetry thermistor system (TT) and thermal camera (TC) during exercise in a hot environment. Each system was compared against a certified thermocouple, measuring the surface temperature of a metal block in a thermostatically controlled waterbath. Fourteen recreational athletes completed two incremental running tests, separated by one week. Skin temperatures were measured simultaneously with TT and TC compared against a hard-wired thermistor system (HW) throughout rest and exercise. Post hoc calibration based on waterbath results displayed good validity for TT (mean bias [MB]=−0.18 °C, typical error [TE]=0.18 °C) and reliability (MB=−0.05 °C, TE=0.31 °C) throughout rest and exercise. Poor validity (MB=−1.4 °C, TE=0.35 °C) and reliability (MB=−0.65 °C, TE=0.52 °C) was observed for TC, suggesting it may be best suited to controlled, static situations. These findings indicate TT systems provide a convenient, valid and reliable alternative to HW, useful for measurements in the field where traditional methods may be impractical. 相似文献
8.
IntroductionCerebral blood flow and thermal perception during physical exercise under hyperthermia conditions in females are poorly understood. Because sex differences exist for blood pressure control, resting middle cerebral artery velocity (MCAVmean), and pain, we tested the hypothesis that females would have greater reductions in MCAvmean and increased thermal perceptual strain during exercise hyperthermia compared to males.MethodsTwenty-two healthy active males and females completed 60 min of matched exercise metabolic heat production in a 1) control cool (24.0 ± 0.0 °C; 14.4 ± 3.4% Rh) and 2) hot (42.3 ± 0.3 °C; 28.4 ± 5.2% Rh) conditions in random order, separated by at least 3 days while MCAvmean, thermal comfort, and preference was obtained during the exercise.ResultsCompared to 36 °C mean body temperature (Mbt), as hyperthermia increased to 39 °C Mbt, females had a greater reduction in absolute (MCAvmean), and relative change (%Δ MCAvmean) and conductance (%Δ MCAvmean conductance) in MCAVmean compared to males (Interaction: Temperature x Sex, P ≤ 0.002). During exercise in cool conditions, absolute and conductance MCAvmean was maintained from rest through exercise; however, females had greater MCAVmean compared to males (Main effect: Sex, P < 0.0008). We also found disparities in females' perceptual thermal comfort and thermal preference. These differences may be associated with a greater reduction in partial pressure of end-tidal CO2, and different cardiovascular and blood pressure control to exercise under hyperthermia.ConclusionsIn summary, females exercise cerebral blood flow velocity is reduced to a greater extent (25% vs 15%) and the initial reduction occurs at lower hyperthermia mean body temperatures (~38 °C vs ~39 °C) and are under greater thermal perceptual strain compared to males. 相似文献
9.
C Zinner M Krueger JL Reed M Kohl-Bareis H-C Holmberg B Sperlich 《Biology of sport / Institute of Sport》2016,33(1):71-76
In this study, we tested the hypothesis that breathing hyperoxic air (FinO2 = 0.40) while exercising in a hot environment exerts negative effects on the total tissue level of haemoglobin concentration (tHb); core (Tcore) and skin (Tskin) temperatures; muscle activity; heart rate; blood concentration of lactate; pH; partial pressure of oxygen (PaO2) and carbon dioxide; arterial oxygen saturation (SaO2); and perceptual responses. Ten well-trained male athletes cycled at submaximal intensity at 21°C or 33°C in randomized order: first for 20 min while breathing normal air (FinO2 = 0.21) and then 10 min with FinO2 = 0.40 (HOX). At both temperatures, SaO2 and PaO2, but not tHb, were increased by HOX. Tskin and perception of exertion and thermal discomfort were higher at 33°C than 21°C (p < 0.01), but independent of FinO2. Tcore and muscle activity were the same under all conditions (p > 0.07). Blood lactate and heart rate were higher at 33°C than 21°C. In conclusion, during 30 min of submaximal cycling at 21°C or 33°C, Tcore, Tskin and Tbody, tHb, muscle activity and ratings of perceived exertion and thermal discomfort were the same under normoxic and hyperoxic conditions. Accordingly, breathing hyperoxic air (FinO2 = 0.40) did not affect thermoregulation under these conditions. 相似文献
10.
This study aimed to search for relations between body fat percentage and skin temperature and to describe possible effects on skin temperature as a result of fat percentage in each anatomical site. Women (26.11±4.41 years old) (n =123) were tested for: body circumferences; skin temperatures (thermal camera); fat percentage and lean mass from trunk, upper and lower limbs; and body fat percentage (Dual-Energy X-Ray Absorptiometry). Values of minimum (TMi), maximum (TMa), and mean temperatures (TMe) were acquired in 30 regions of interest. Pearson's correlation was estimated for body circumferences and skin temperature variables with body fat percentage. Participants were divided into groups of high and low fat percentage of each body segment, of which TMe values were compared with Student's t-test. Linear regression models for predicting body fat percentage were tested. Body fat percentage was positively correlated with body circumferences and palm temperatures, while it was negatively correlated with most temperatures, such as TMa and TMe of posterior thighs (r =−0.495 and −0.432), TMe of posterior lower limbs (r =−0.488), TMa of anterior thighs (r =−0.406) and TMi and TMe of posterior arms (r =−0.447 and −0.430). Higher fat percentages in the specific anatomical sites tended to decrease TMe, especially in posterior thighs, shanks and arms. Skin temperatures and body circumferences predicted body fat percentage with 58.3% accuracy (R =0.764 and R2 =0.583). This study clarifies that skin temperature distribution is influenced by the fat percentage of each body segment. 相似文献
11.
Skin temperature is an essential physiological parameter of thermal comfort. The purpose of this research was to reveal the effects of clothing thermal resistance and operative temperature on local skin temperature (LST) and mean skin temperature (MST). The LSTs (at 32 sites) in stable condition were measured for different clothing thermal resistances 1.39, 0.5 and 0.1 clo. To study the effect of environmental temperature on LST and MST, the LSTs were also measured for operative temperatures 23, 26 and 33 °C. The experimental data showed that the effect of clothing thermal resistance on the foot was greater compared to the other human parts, and the effect of operative temperature on many parts of the human body was great, such as foot, hand, trunk, and arm. The MSTs measured on the conditions that air speed was under 0.1 m/s, RH was about 30–70%, and metabolic rate was about 1 met, were collected from previous studies. On the basis of these experimental data, a MST prediction equation with the operative temperature and clothing thermal resistance as independent variables, was obtained by multiple linear regression. This equation was a good alternative and provided convenience to predict the MST in different operative temperatures and clothing thermal resistances. 相似文献
12.
While different studies showed that better fitness level adds to the efficiency of the thermoregulatory system, the relationship between muscular effort and skin temperature is still unknown. Therefore, the present study assessed the relationship between neuromuscular activation and skin temperature during cycle exercise. Ten physically active participants performed an incremental workload cycling test to exhaustion while neuromuscular activations were recorded (via surface electromyography – EMG) from rectus femoris, vastus lateralis, biceps femoris and gastrocnemius medialis. Thermographic images were recorded before, immediately after and 10 min after finishing the cycling test, at four body regions of interest corresponding to the muscles where neuromuscular activations were monitored. Frequency band analysis was conducted to assess spectral properties of EMG signals in order to infer on priority in recruitment of motor units. Significant inverse relationship between changes in skin temperature and changes in overall neuromuscular activation for vastus lateralis was observed (r<−0.5 and p<0.04). Significant positive relationship was observed between skin temperature and low frequency components of neuromuscular activation from vastus lateralis (r>0.7 and p<0.01). Participants with larger overall activation and reduced low frequency component for vastus lateralis activation presented a better adaptive response of their thermoregulatory system by showing fewer changes in skin temperature after incremental cycling test. 相似文献
13.
Internal and external factors contribute to resting core temperature and affect thermoregulation. Also, a robust circadian rhythm exists, implying that the body is in “heat-gain” or “heat-loss” modes at different times during the 24 h. Moreover, many variables associated with exercise, and the body's capacity for exercise, show circadian variation. All these factors contribute to circadian changes in thermoregulation during exercise. Attention is focused on responses at the onset of exercise, “critical temperature”, and recovery after exercise. Practical implications of circadian changes in thermoregulation during exercise include ergogenic aids and inter-individual differences, including those due to gender, age and acclimatisation. 相似文献
14.
The experiment was conducted to investigate the human thermoregulatory responses during rest, exercise and recovery atT
a 20°C and 60% R.H. under the conditions of wearing two different types of clothing. Six healthy men wore two types of clothing: one covering the whole body area except the head (Type A, weight 1656 g), and the other covering only the trunk, upper arms and thighs (Type B, weight 996 g). The level of rectal temperature was kept significantly higher in Type B than in Type A during rest and recovery. The increased and decreased rates of rectal temperature during exercise and recovery were significantly greater in Type A than in Type B, respectively. These findings are discussed from the viewpoint of the differences of skin temperatures of the extremities between Type A and Type B. 相似文献
15.
Mohammad Fahim 《International journal of biometeorology》1992,36(1):5-9
Effect of hypoxia (12% O2) on skin temperature recovery was studied on healthy young men. Forty male volunteers free of any respiratory disorder were randomly selected to participate in the study. Skin temperature, peripheral blood flow, heart rate and end expiratoryPO2 andPCO2 were measured. During hyoxic ventilation the peripheral blood flow was reduced and a corresponding drop in skin temperature occurred. This was partly due to hyperventilation associated with hypoxic ventilation. The recovery of skin temperature after cooling the hand for 2 min in cold water (10–12° C) took 5.5±0.1 min during normal air breathing; during hypoxic ventilation even after 9.1±0.3 min when the skin temperature recovery curve plateaued, the skin temperature remained about 2° C below control. The results of the present investigation indicate that hypoxia interferes with the normal functioning of the thermoregulatory mechanism in man. Hyperventilation associated with hypoxic ventilation is also partly responsible for incomplete recovery of skin temperature. 相似文献
16.
Arteriovenous anastomoses (AVA) in acral skin (palms and soles) have a huge capacity to shunt blood directly from the arteries to the superficial venous plexus of the extremities. We hypothesized that acral skin, which supplies blood to the superficial venous plexus, has a stronger influence on blood flow adjustments during cooling in thermoneutral subjects than does non-acral skin. Thirteen healthy subjects were exposed to stepwise cooling from 32 °C to 25 °C and 17 °C in a climate chamber. Laser Doppler flux and skin temperature were measured simultaneously from the left and right third finger pulp and bilateral upper arm skin. Coherence and correlation analyses were performed of short-term fluctuations at each temperature interval. The flux from finger pulps showed the synchronous spontaneous fluctuations characteristic of skin areas containing AVAs. Fluctuation frequency, amplitude and synchronicity were all higher at 25 °C than at 32 °C and 17 °C (p<0.02). Bilateral flux from the upper arm skin showed an irregular, asynchronous vasomotor pattern with small amplitudes which were independent of ambient temperature. At 32 °C, ipsilateral median flux values from the right arm (95% confidence intervals) were 492 arbitrary units (au) (417, 537) in finger pulp and 43 au (35, 60) in upper arm skin. Flux values gradually decreased in finger pulp to 246 au (109, 363) at 25 °C, before an abrupt fall occurred at a median room temperature of 24 °C, resulting in a flux value of 79 au (31, 116) at 17 °C. In the upper arm skin a gradual fall throughout the cooling period to 21 au (13, 27) at 17 °C was observed. The fact that the response of blood flow to ambient cooling is stronger in acral skin than in non-acral skin suggests that AVAs have a greater capacity to adjust blood flow in thermoneutral zone than arterioles in non-acral skin. 相似文献
17.
BackgroundHypothermia is a problem for very premature infants after birth and leads to increased morbidity and mortality. Previously we found very premature infants exhibit abnormal thermal patterns, keeping foot temperatures warmer than abdominal temperatures for their first 12 h of life.PurposeWe explored the utility of infrared thermography as a non-invasive method for measuring body temperature in premature infants in an attempt to regionally examine differential temperatures.ResultsOur use of infrared imaging to measure abdominal and foot temperature for extremely premature infants in heated, humid incubators was successful and in close agreement using Bland and Altman technique with temperatures measured by skin thermistors.ConclusionsOur study methods demonstrated that it was feasible to capture full body temperatures of extremely premature infants while they were resting in a heated, humid incubator using a Flir SC640 infrared camera. This technology offers researchers and clinicians a method to examine acute changes in perfusion differentials in premature infants which may lead to morbidity. 相似文献
18.
H. A. M. Daanen F. J. G. Van de Linde T. T. Romet M. B. Ducharme 《European journal of applied physiology and occupational physiology》1997,76(6):538-543
The relationship between body temperature and the hunting response (intermittent supply of warm blood to cold exposed extremities)
was quantified for nine subjects by immersing one hand in 8°C water while their body was either warm, cool or comfortable.
Core and skin temperatures were manipulated by exposing the subjects to different ambient temperatures (30, 22, or 15°C),
by adjusting their clothing insulation (moderate, light, or none), and by drinking beverages at different temperatures (43,
37 and 0°C). The middle finger temperature (T
fi) response was recorded, together with ear canal (T
ear), rectal (T
re), and mean skin temperature (Tˉ
sk). The induced mean T
ear changes were −0.34 (0.08) and +0.29 (0.03)°C following consumption of the cold and hot beverage, respectively. Tˉ
sk ranged from 26.7 to 34.5°C during the tests. In the warm environment after a hot drink, the initial finger temperature (T
fi,base) was 35.3 (0.4)°C, the minimum finger temperature during immersion (T
fi,min) was 11.3 (0.5)°C, and 2.6 (0.4) hunting waves occurred in the 30-min immersion period. In the neutral condition (thermoneutral
room and beverage) T
fi,base was 32.1 (1.0)°C, T
fi,min was 9.6 (0.3)°C, and 1.6 (0.2) waves occurred. In the cold environment after a cold drink, these values were 19.3 (0.9)°C,
8.7 (0.2)°C, and 0.8 (0.2) waves, respectively. A colder body induced a decrease in the magnitude and frequency of the hunting
response. The total heat transferred from the hand to the water, as estimated by the area under the middle finger temperature
curve, was also dependent upon the induced increase or decrease in T
ear and Tˉ
sk. We conclude that the characteristics of the hunting temperature response curve of the finger are in part determined by core
temperature and Tˉ
sk. Both T
fi,min and the maximal finger temperature during immersion were higher when the core temperature was elevated; Tˉ
sk seemed to be an important determinant of the onset time of the cold-induced vasodilation response.
Accepted: 29 April 1997 相似文献
19.
Cassandra D. Haley Christopher J. Gordon Nigel A.S. Taylor Arthur B. Jenkins 《Journal of thermal biology》2004,29(7-8):779-783
In a separate paper, we describe high-amplitude oscillations in human skin blood flow (Q˙sk). Using an open-loop model in rats, we independently modulated and clamped hypothalamic and skin temperatures. Central heating reliably induced these high-amplitude oscillations in tail Q˙sk, which occurred at 0.41±0.03 Hz spanning 758.1±25.7 ms, and were comprised of high-amplitude peaks (496.8±87.6 AU) arising from a stable baseline (114.1±27.6 AU). Central cooling significantly reduced Q˙sk, but not the amplitude, the frequency, width or baseline of the oscillations. These observations indicate that such high-amplitude oscillations are not primarily mediated via central thermal state. Instead, we believe these oscillations to be turned on by an elevated skin temperature. 相似文献
20.
Glen P. Kenny Francis D. Reardon Jim S. Thoden Gordon G. Giesbrecht G. Kenny 《International journal of biometeorology》1999,43(1):8-13
This study evaluates the effect of different levels of insulation on esophageal (T
es) and rectal (T
re) temperature responses during and following moderate exercise. Seven subjects completed three 18-min bouts of treadmill exercise
(75% VO2max, 22°C ambient temperature) followed by 30 min of recovery wearing either: (1) jogging shoes, T-shirt and shorts (athletic
clothing); (2) single-knit commercial coveralls worn over the athletic clothing (coveralls); or (3) a Canadian Armed Forces
nuclear, bacteriological and chemical warfare protective overgarment with hood, worn over the athletic clothing (NBCW overgarment).
T
es was similar at the start of exercise for each condition and baseline T
re was ∼0.4°C higher than T
es. The hourly equivalent rate of increase in T
es during the final 5 min of exercise was 1.8°C, 3.0°C and 4.2°C for athletic clothing, coveralls and NBCW overgarment respectively
(P<0.05). End-exercise T
es was significantly different between conditions [37.7°C (SEM 0.1°C), 38.2°C (SEM 0.2°C and 38.5°C (SEM 0.2°C) for athletic
clothing, coveralls and NBCW overgarment respectively)] (P<0.05). No comparable difference in the rate of temperature increase for T
re was demonstrated, except that end-exercise T
re for the NBCW overgarment condition was significantly greater (0.5°C) than that for the athletic clothing condition. There
was a drop in T
es during the initial minutes of recovery to sustained plateaus which were significantly (P<0.05) elevated above pre-exercise resting values by 0.6°C, 0.8°C and 1.0°C, for athletic clothing, coveralls, and NBCW overgarment,
respectively. Post-exercise T
re decreased very gradually from end-exercise values during the 30-min recovery. Only the NBCW overgarment condition T
re was significantly elevated (0.3°C) above the athletic clothing condition (P<0.05). In conclusion, T
es is far more sensitive in reflecting the heat stress of different levels of insulation during exercise and post-exercise than
T
re. Physiological mechanisms are discussed as possible explanations for the differences in response.
Received: 30 June 1998 / Accepted: 19 February 1999 相似文献