This review discusses human thermoregulation during exercise and the measurement of body temperature in clinical and exercise settings. The thermoregulatory mechanisms play important roles in maintaining physiological homeostasis during rest and physical exercise. Physical exertion poses a challenge to thermoregulation by causing a substantial increase in metabolic heat production. However, within a non-thermolytic range, the thermoregulatory mechanisms are capable of adapting to sustain physiological functions under these conditions. The central nervous system may also rely on hyperthermia to protect the body from "overheating." Hyperthermia may serve as a self-limiting signal that triggers central inhibition of exercise performance when a temperature threshold is achieved. Exposure to sub-lethal heat stress may also confer tolerance against higher doses of heat stress by inducing the production of heat shock proteins, which protect cells against the thermolytic effects of heat. Advances in body temperature measurement also contribute to research in thermoregulation. Current evidence supports the use of oral temperature measurement in the clinical setting, although it may not be as convenient as tympanic temperature measurement using the infrared temperature scanner. Rectal and oesophagus temperatures are widely accepted surrogate measurements of core temperature (Tc), but they cause discomfort and are less likely to be accepted by users. Gastrointestinal temperature measurement using the ingestible temperature sensor provides an acceptable level of accuracy as a surrogate measure of Tc without causing discomfort to the user. This form of Tc measurement also allows Tc to be measured continuously in the field and has gained wider acceptance in the last decade.
Body Temperature ; physiology ; Body Temperature Regulation ; physiology ; Exercise ; physiology ; Humans ; Monitoring, Physiologic ; methods

AIMTo investigate the sweat regulation mechanism of human body.

METHODSArm muscular work was performed on bicycle ergometer by eight healthy male subjects on 20 W and 40 W work loads lasting 10 min or 20 min in 16 degrees C and 21 degrees C ambient temperature. Sweat, metabolic rate and corresponding skin and core temperature changes were measured during different periods.

RESULTSSweat varied directly with ambient temperature and there were the corresponding changes in mean skin temperature, rectal temperature and metabolic rate. And when the work load was elevated, the skin temperature at chest and metabolic rate increased as sweat increased. There were no differences in the physiological indices between 20 W 20 min and 20 W 10 min, but mean skin temperature and sweat rate during 40 W 20 min work were higher than 40 W 10 min while metabolic rate did not change. The time when chest temperature arrived at the threshold was in correspondence with obvious sweat onset. Both local skin temperature at chest and metabolic rate were significantly correlated with sweat, but the latter was stronger. The regression equation relating metabolic rate and sweat rate was compound function.

CONCLUSIONSkin temperature was important for sweat onset, and the sweat predicted model based on the metabolic rate or ambient temperature was more suitable and practical.

Adult ; Body Temperature Regulation ; physiology ; Energy Metabolism ; Environment ; Humans ; Male ; Sweating ; physiology ; Temperature

OBJECTIVEThis study was aimed to explore the physiological changes and the effect of heat acclimation training via a randomized control trial study.

METHODSForty healthy male volunteers were chosen and divided into experimental group and control group randomly. Those in experimental group received heat acclimation training including but not limited to meditation, unarmed run, yoga, and stepping in hot lab environment. And then, subjective feeling, rectal temperature, average skin temperature, and sweat electrolytes concentration were detected in order to describe their physiological changes. Before and after the training, both groups received some tests and their 3 000 m run-race time, nervous reaction time and subjective perception scores were recorded to evaluate the effect of acclimation training.

RESULTS(1) There was no difference in 3 000 m between the 2 groups in the same environment. Subjects' 3 000 m race time in experimental group was obviously shortened than that in control group in room temperature environment (t = 2.326, P < 0.05). And subjects' 3 000 m race time in experimental group was obviously shortened than that in control group in hot-humid environment (t = 4.518, P < 0.01). (2) Subjects' reaction time (RT) in experimental group was shortened than that in control group in room temperature environment (Z = 11.258, P < 0.05). And Subjects' RT in experimental group was sharply shortened than that in control group in hot-humid environment (Z = 6.519, P < 0.01). (3) No difference between the experimental and control groups was observed in subjective perception score (SPS) in room temperature environment. But subjects' SPS in experimental group was obviously lowered than that in control group and in hot-humid environment (t = 17.958, P < 0.01).(4) Anal temperature (AT) was lowered during training, while the change of mean skin temperature (MST) was not significant. Sweat sodium concentration (SSC) was lowered during training. SPS continued to decrease and entered plateau on the 13th day after training.(5) After acclimation training, the working capacity of the experimental group in hot-humid environment was over 85% of that in room temperature environment. While subjects' working capacity in control group in hot-humid environment was about 80% of that in room temperature environment.

CONCLUSIONHot-humid environment acclimation training improved the working capacity. After training, subjects' working capacity in hot-humid environment remained over 85% of that in room temperature environment, which was higher than that of those subjects who did not take part in training.

Acclimatization ; physiology ; Body Temperature ; Heart Rate ; Hot Temperature ; Humans ; Humidity ; Male ; Physical Conditioning, Human ; physiology ; Sweating

Aging is a process of the progressive functional decline with time, leading to disability, dependence, morbidity, and mortality. While the organ function in the elderly is relatively uncompromised under basal conditions, their ability to tolerate increased physiologic stress is reduced. And the extent and onset of the deterioration in functional reserve is quite diverse from patient to patient. The aging population is rapidly growing and their medical management is becoming one of the greatest challenges to anesthesiologists. The understanding of the normal physiologic changes with aging is essential to frame any discussion of perioperative management in the elderly. In this review, we will focus on the physiologic changes in neurologic, cardiac, pulmonary, renal, and hepatic function, and thermoregulation.
Aged ; Aging* ; Body Temperature Regulation ; Humans ; Mortality ; Physiology

Circadian rhythm is a periodic and continuous change in physiological, behavioral, and mental characteristics that occurs in most organisms on the Earth, because the Earth rotates in a 24-hour cycle. The circadian system regulates daily rhythms of physiology and behavior, such as the sleep/wake cycle, body temperature, hormonal secretion, and mood. The influence of circadian rhythm is very powerful, but limited research has addressed its effects. However, many recent studies have shown that circadian dysregulation may play an important role in the pathogenesis of bipolar disorder. This review study examined current and noteworthy studies, including the authors' own works, and proposes a possible clinical application of bipolar disorder based on evidence that circadian rhythm dysregulation in bipolar disorder may be a key pathogenetic mechanism.
Bipolar Disorder* ; Body Temperature ; Chronobiology Disorders ; Circadian Rhythm* ; Physiology

Mild hypothermia, as a common means of intraoperative nerve protection, has been used in clinical practice. Compared with the traditional methods such as freezing helmet and nasopharyngeal cooling, hypothermic blood perfusion is considered to be a promising treatment for mild hypothermia, but it lacks experimental and theoretical verification of its cooling effect. In this study, the commercial finite element simulation software COMSOL combined the Pennes equation with the cerebrovascular network model to construct a new simplified human brain model, which was further used to simulate the cooling process of cerebral hypothermic blood perfusion. When the hypothermic blood perfusion was 33 ℃, the human brain could enter the mild hypothermic state within 4 minutes. By comparing with helmet cooling, the feasibility and efficiency of the blood perfusion scheme were verified. By comparing with the calculation results based on Pennes equation, the rationality of the model constructed in this study were verified. This model can non-intrusively predict the changes of brain temperature during surgery, and provide a reference for the setting of treatment parameters such as blood temperature, so as to provide personalized realization of safer and more effective mild hypothermia neuro protection.
Humans ; Hypothermia, Induced/methods* ; Hypothermia ; Hemoperfusion ; Brain/physiology* ; Body Temperature

The present study was performed in order to test the effects of diphenylhydantoin (DPH) and two central nervous system (CNS) stimulants, intermittent light stimulation(ILS) and pentylenetetrazol (Metrazol) on body temperature (Tb) during cold exposure in the bat DHP delayed the onset of entry into hibernation in both the oriental discoloured bats and the little brown bats and formed long and prominent plateaus that were not found in the normal and the controls. The responses of body temperature to the ILS were sensitive and the body temperature fell dramatically in the big brown bats. Metrazol effects on body temperature were obvious but; seemed dose-dependent. The experimental results further support the hypothesis that hibernation is an epileptic fit as suggested by serveral researchers.
Animal ; Body Temperature/drug effects ; Body Temperature Regulation ; Chiroptera/physiology* ; Female ; Hibernation* ; Light ; Male ; Pentylenetetrazole/pharmacology ; Phenytoin/pharmacology

The present study was performed to investigate the effect on the skin and the intra-articular structures of 5-minutes of cold air application. During and after 5 minutes of cold air application on 20 healthy subjects, the skin and intra-articular temperatures were measured by means of an infrared thermogram and a digital k-wire probe, respectively. The results showed that 1) Skin temperature dropped very rapidly by a total of 22.1 degrees C after 5 minutes of cold air application. 2) Intra-articular temperature dropped by 3.9 degrees C after 5 minutes of cold air application. 3) Two hours after the start of treatment with cold air, intra-articular temperatures had still not returned to their baseline values (p < 0.01). 4) The baseline skin temperature and the baseline intra-articular temperature were significantly correlated r=0.51 (p < 0.05). However, there was no significant correlation between the skin temperature change and the intra-articular temperature change after 5 minutes and after two hours of cold air application. Finally, 5) a significant correlation r=-0.72 (p < 0.01) between the body mass index and the baseline skin temperatures was found. There was no significant correlation between the body mass index and the temperature changes, at the skin or in the knee joint, either during or after cryotherapy (p > 0.05).
Adult ; Aged ; Body Mass Index ; *Body Temperature ; *Cryotherapy ; Female ; Human ; Knee Joint/*physiology ; Male ; Middle Age ; *Skin Temperature

The parameters which can influence heat transfer of tongue were analyzed in order to reveal the reason why the tongue temperature fields of people with different diseases are distinct. Firstly, the research parameters were determined by experiment results, including the reference humidity of tongue surface, metabolic heat of tongue tissue, the entrance position of root vessel, the diameter of root vessel, the blood flow rate, and the bifurcation exponent of vascular tree. Then the effect of each parameter on the value and the distributing rule of tongue temperature field was analyzed by using a mathematic model of lingual temperature field. Results show that all these parameters have effects on the temperature value of tongue. The reference humidity of tongue surface, the metabolic heat of tongue tissue and the entrance position of root vessel are distinct influences on the distributing rule of tongue temperature.
Body Temperature ; physiology ; Humans ; Humidity ; Models, Theoretical ; Regional Blood Flow ; Thermal Conductivity ; Tongue ; blood supply ; physiology

PURPOSE: The purpose of this study was designed to identify the effects of heat therapy on dysmenorrhea, heat being provided using a far infrared rays heating element. METHODS: The research design for the study was a non-equivalent control group quasi-experimental design. Participants were 22 students for the experimental group, and 26 students for the control group. Data were analyzed using SAS WIN 9.1 program. RESULTS: The experimental group had significantly lower mean scores for menstrual pain, dysmenorrhea, and blood pressure than those in the control group. However, no significant differences were found between two groups for pulse, respiration, and temperature. CONCLUSION: These findings show that thermotherapy was effective for reduction of menstrual pain, dysmenorrhea, and B/P. Therefore, this therapy could be used as a nursing intervention for students with dysmenorrhea.
Abdomen/radiation effects ; Adolescent ; Blood Pressure/physiology ; Body Temperature/physiology ; Child ; Dysmenorrhea/prevention & control/*therapy ; Female ; Heart Rate/physiology ; *Hot Temperature ; Humans ; *Infrared Rays ; Respiration