Drop In Skin Temperature Research Articles

Coupling of winter climate transitions to snow and clouds over the Prairies

AbstractUsing data from 13 climate stations on the Canadian Prairies, together with opaque cloud cover and daily snow depth, to analyze the winter climate transitions with snow, we find that a snow cover acts as a fast climate switch. Surface temperature falls by about 10 K with fresh snowfall and rises by a similar amount with snowmelt, while the daily range of relative humidity falls to around 5–15% with snow cover. These are robust climate signals. For every 10% decrease in days with snow cover over the Canadian Prairies, the mean October to April climate is warmer by about 1.4 K. Stratifying by daily mean opaque cloud cover across snow transitions shows the rapid shift within 5 days from a diurnal cycle dominated by shortwave cloud forcing to one dominated by longwave cloud forcing. We calculate the change in the surface radiative budget with snow using surface albedo data from the Moderate Resolution Imaging Spectroradiometer and station longwave data. We find that with the fall‐winter snow transitions, the surface radiative heating is reduced by 50 Wm−2, with 69% coming from the reduced net shortwave flux, resulting from the increased surface albedo and a small increase in effective cloud albedo, and 31% from a reduced incoming longwave flux. This drop in surface radiative heating is sufficient to produce a drop in the surface radiometric skin temperature of 11 K. We find that in winter, the monthly mean diurnal climate is more closely coupled to the diurnal shortwave forcing than the mean diurnal climate.

A new mathematical model to simulate AVA cold-induced vasodilation reaction to local cooling

The purpose of this work was to integrate a new mathematical model with a bioheat model, based on physiology and first principles, to predict thermoregulatory arterio-venous anastomoses (AVA) and cold-induced vasodilation (CIVD) reaction to local cooling. The transient energy balance equations of body segments constrained by thermoregulatory controls were solved numerically to predict segmental core and skin temperatures, and arterial blood flow for given metabolic rate and environmental conditions. Two similar AVA-CIVD mechanisms were incorporated. The first was activated during drop in local skin temperature (<32 °C). The second mechanism was activated at a minimum finger skin temperature, T(CIVD, min), where the AVA flow is dilated and constricted once the skin temperature reached a maximum value. The value of T(CIVD,min) was determined empirically from values reported in literature for hand immersions in cold fluid. When compared with published data, the model predicted accurately the onset time of CIVD at 25 min and T(CIVD,min) at 10 °C for hand exposure to still air at 0 °C. Good agreement was also obtained between predicted finger skin temperature and experimentally published values for repeated immersion in cold water at environmental conditions of 30, 25, and 20 °C. The CIVD thermal response was found related to core body temperature, finger skin temperature, and initial finger sensible heat loss rate upon exposure to cold fluid. The model captured central and local stimulations of the CIVD and accommodated observed variability reported in literature of onset time of CIVD reaction and T(CIVD,min).

Thermoregulation of Premature Infants during and after Skin-to-Skin Care

Providing normothermia is an important issue in daily routine care of premature neonates. We recently found with infrared thermography (IRT) a drop in skin temperature of premature babies after they were positioned from skin-to-skin care (SSC) back into the incubator. Since this did not disappear within 10 min, we wanted to find out how long it takes until the baby has fully warmed up after SSC and if the IRT measurements correlate with conventional rectal temperature? A prospective observational study was undertaken with 5 premature infants [3 male, median gestational age 28 weeks (25-29), median age at study 34 d (28-52), median birth weight 898 g (400-1095), median weight at study 1263 g (790-1465)], temperature was determined with IRT (leg, back, arm, head, upper abdomen; diameter 1 cm, scale 0.00°C), comparison with 2 conventional sensors and rectal temperature. Temperatures were recorded every 2 min and displayed for 4 time points, namely at the beginning and the end of skin-to-skin care (SSC1, SSC2), as well as at the beginning and the end of a subsequent 60 min incubator period (I). A significant rise during SSC occurred while the cooling after SSC persisted during the complete incubator measurement time (I; p<0.05). Rectal temperature remained stable through the whole measuring period. While SSC in our setting led to an increase in temperature, the lack of compensation of peripheral heat loss in the incubator after 60 min may express an inadequate peripheral regulation of body temperature. This should be taken into account before routine care after SSC.

Comfort and performance of power line maintainers' gloves during electrical utility work in the cold

Electrical utility workers wear thick rubber gloves and often work in the cold. To document the challenge of working in the cold and the effectiveness of different glove/liner combinations in keeping workers' hands warm. Ten experienced male electrical utility employees worked in a controlled temperature walk-in chamber at -20 °C for 45 minutes for each of five glove conditions: standard five-finger rubber gloves with cotton liners and gauntlets, mitten style gloves, a prototype wool liner, and two heating options; glove or torso. Dependent measures were maximum grip force, skin temperatures, finger dexterity and sensitivity to touch, ratings of perceived effort and a rating of thermal sensation. Participants' hand skin temperatures decreased, they perceived their hands to be much colder, their finger sensitivity decreased and their ratings of perceived exertion increased, however their performance did not degrade over the 45 minute trials. The mitten-style gloves showed a smaller drop in skin temperature for the 3rd and 5th digits (p< 0.05) than the other glove conditions. Mitten style gloves kept workers' hands warmer than the standard five finger glove.

Dorsal and Ventral Hippocampus Modulate Autonomic Responses but Not Behavioral Consequences Associated to Acute Restraint Stress in Rats

Recent evidence has suggested that the dorsal (DH) and the ventral (VH) poles of the hippocampus are structurally, molecularly and functionally different regions. While the DH is preferentially involved in the modulation of spatial learning and memory, the VH modulates defensive behaviors related to anxiety. Acute restraint is an unavoidable stress situation that evokes marked and sustained autonomic changes, which are characterized by elevated blood pressure (BP), intense heart rate (HR) increases, skeletal muscle vasodilatation and cutaneous vasoconstriction, which are accompanied by a rapid skin temperature drop followed by body temperature increases. In addition to those autonomic responses, animals submitted to restraint also present behavioral changes, such as reduced exploration of the open arms of an elevated plus-maze (EPM), an anxiogenic-like effect. In the present work, we report a comparison between the effects of pharmacological inhibition of DH and VH neurotransmission on autonomic and behavioral responses evoked by acute restraint stress in rats. Bilateral microinjection of the unspecific synaptic blocker cobalt chloride (CoCl2, 1mM) into the DH or VH attenuated BP and HR responses, as well as the decrease in the skin temperature, elicited by restraint stress exposure. Moreover, DH or VH inhibition before restraint did not change the delayed increased anxiety behavior observed 24 h later in the EPM. The present results demonstrate for the first time that both DH and VH mediate stress-induced autonomic responses to restraint but they are not involved in the modulation of the delayed emotional consequences elicited by such stress.

Prolonged physical inactivity leads to a drop in toe skin temperature during local cold stress

The purpose was to examine the effects of a prolonged period of recumbency on the toe temperature responses during cold-water foot immersion. Ten healthy males underwent 35 days of horizontal bed rest. The right foot of the subjects was assigned as the experimental (EXP) foot. To prevent bed rest-induced vascular deconditioning in the left control foot (CON), a sub-atmospheric vascular pressure countermeasure regimen was applied on the left lower leg for 4 × 10 min every second day. On the first (BR-1) and the last (BR-35) day of the bed rest, subjects performed two 30 min foot immersion tests in 8 °C water, one with the EXP foot and the other with the CON foot. The tests were conducted in counter-balanced order and separated by at least a 15 min interval. At BR-35, the average skin temperature of the EXP foot was lower than at BR-1 (-0.8 °C; P = 0.05), a drop that was especially pronounced in the big toe (-1.6 °C; P = 0.05). In the CON foot, the average skin temperature decreased by 0.6 °C in BR-35, albeit the reduction was not statistically significant (P = 0.16). Moreover, the pressure countermeasure regimen ameliorated immersion-induced thermal discomfort for the CON foot (P = 0.05). Present findings suggest that severe physical inactivity exaggerates the drop in toe skin temperature during local cold stress, and thus might constitute a potential risk factor for local cold injury.

AB0739 Infrared thermography of big toe in raynaud’s phenomenon

BackgroundThe thermography measures blood flow indirectly by measuring skin surface temperature [1]. The characteristic of Raynaud phenomenon is cold-induced vasoconstriction in distal extremities which in turn, lowers skin temperature.ObjectivesThe aim...

Early Skin-to-Skin Care in Extremely Preterm Infants: Thermal Balance and Care Environment

To evaluate infant thermal balance and the physical environment in extremely preterm infants during skin-to-skin care (SSC). Measurements were performed in 26 extremely preterm infants (gestational age 22-26 weeks; postnatal age, 2-9 days) during pretest (in incubator), test (during SSC), and posttest (in incubator) periods. Infants' skin temperature and body temperature, ambient temperature, and relative humidity were measured. Evaporimetry was used to determine transepidermal water loss, and insensible water loss through the skin was calculated. The infants maintained a normal body temperature during SSC. Transfer to and from SSC was associated with a drop in skin temperature, which increased during SSC. Ambient humidity and temperature were lower during SSC than during incubator care. Insensible water loss through the skin was higher during SSC. SSC can be safely used in extremely preterm infants. SSC can be initiated during the first week of life and is feasible in infants requiring neonatal intensive care, including ventilator treatment. During SSC, the conduction of heat from parent to infant is sufficiently high to compensate for the increase in evaporative and convective heat loss. The increased water loss through the skin during SSC is small and should not affect the infant's fluid balance.

The rubber hand illusion increases histamine reactivity in the real arm

Summary Most people are convinced that their body parts are in fact their own, but in some clinical conditions, this sense of ownership can be lost [1]. Perceptual illusions, most famously the rubber hand illusion (RHI) [2], demonstrate that a sense of ownership over a body part (or an entire body [3]) that is not in fact ours can be easily induced in healthy volunteers. But does illusory ownership over an artificial body part have consequences for the real body part, the one that has been ‘replaced'? Recent data show the RHI induces a small but robust drop in skin temperature of the real hand. That is, blood flow to the ‘disowned' hand seems to be selectively reduced [1]. Such a finding is particularly relevant to the immune system because a primary role of the immune system is to ‘discriminate self from non-self' [4]. We predicted that the innate immune system may be upregulated in a manner consistent with rejection of the replaced hand. Consistent with this prediction, we report here that the RHI increases histamine reactivity, which is a key final pathway of the innate immune response and has been implicated in autoimmune disorders, including multiple sclerosis [5]. Our finding has direct implications for autoimmune disorders and a range of neurological and psychiatric conditions characterised by a disrupted sense of ownership over one's body (see [1] for a list of conditions), and has broader implications that extend well beyond previous assertions about the mind-body link.

The effect of turbulence intensity on local skin temperature and subjective responses to draft

The aim of the present study was to investigate whether turbulence intensity affects local skin temperature drop, and whether subjects’ dissatisfaction with draft can be correlated to the local skin temperature drop. Eighteen subjects were exposed to two levels of turbulence intensity (15% and 30%) at mean air velocities of 0.3 and 0.6m/s respectively for 1h. Subjective responses to draft were registered every 10min and skin temperatures at the back of the neck were recorded throughout the sessions. More subjects felt uncomfortable due to draft when exposed to high turbulence than exposed to low turbulence. Skin temperature drop after 1h exposure under high turbulence intensity is significantly larger than that under low turbulence intensity. Percentage of subjects dissatisfied with draft positively correlated to the local skin temperature drop.

Intravenous saline injection as an interoceptive signal in rats

Addictive drugs are commonly delivered in the organism by means of intravenous (i.v.) injections. Since saline mimics the blood environment by basic ionic properties and pH, it is generally assumed that it should not have any physiological effects, serving as a control for the effects induced by drugs. The aim of the study was to examine central, behavioral, and physiological effects of stress- and cue-free i.v. saline injection in freely moving rats. We examined how a typical low-volume and slow-speed saline injections affect cortical electroencephalograpy (EEG), neck electromyography (EMG), locomotor activity as well as central and peripheral temperatures. Saline injection made during slow-wave synchronized activity induces rapid transient EEG desynchronization, manifesting as a drop of EEG total power, decrease in alpha activity, and increases in beta and gamma activities. Saline injection did not affect locomotor activity as well as brain and body temperatures, but induced a transient increase in neck EMG activity and a rapid brief drop in skin temperature, suggesting peripheral vasoconstriction. These responses were virtually fully absent when saline injection was made during naturally occurring desynchronized EEG activity during behavioral activity. Since i.v. injection is able to produce a peripheral sensory signal that is transmitted rapidly to the CNS and followed by a more prolonged effect of the injected drug on brain cells, with repeated drug administrations, the injection itself could play a role of drug-related sensory cue, thus inducing conditioned physiological responses and altering the effects of injected drugs.

Brown Adipose Tissue, Whole‐Body Energy Expenditure, and Thermogenesis in Healthy Adult Men

Brown adipose tissue (BAT) can be identified by (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in adult humans. Thirteen healthy male volunteers aged 20-28 years underwent FDG-PET after 2-h cold exposure at 19°C with light-clothing and intermittently putting their legs on an ice block. When exposed to cold, 6 out of the 13 subjects showed marked FDG uptake into adipose tissue of the supraclavicular and paraspinal regions (BAT-positive group), whereas the remaining seven showed no detectable uptake (BAT-negative group). The BMI and body fat content were similar in the two groups. Under warm conditions at 27°C, the energy expenditure of the BAT-positive group estimated by indirect calorimetry was 1,446 ± 97kcal/day, being comparable with that of the BAT-negative group (1,434 ± 246kcal/day). After cold exposure, the energy expenditure increased markedly by 410 ± 293 (P < 0.05) and slightly by 42 ± 114kcal/day (P = 0.37) in the BAT-positive and -negative groups, respectively. A positive correlation (P < 0.05) was found between the cold-induced rise in energy expenditure and the BAT activity quantified from FDG uptake. After cold exposure, the skin temperature in the supraclavicular region close to BAT deposits dropped by 0.14°C in the BAT-positive group, whereas it dropped more markedly (P < 0.01) by 0.60°C in the BAT-negative group. The skin temperature drop in other regions apart from BAT deposits was similar in the two groups. These results suggest that BAT is involved in cold-induced increases in whole-body energy expenditure, and, thereby, the control of body temperature and adiposity in adult humans.

Facial skin temperature decreases in infants with joyful expression

Studies of infant emotion rely on the assessment of expressive behavior and physiological response because infants cannot tell their feelings. Little is known about the physiological response of infants when they are in a joyful emotion. In this study, we examined changes in facial skin temperature as a physiological response, when infants are laughing, an expressive behavior of joyful emotion. Using thermography, skin temperatures of the nose, forehead and cheek were evaluated at 2–3 months, 4–6 months and 8–10 months. A decrease in facial skin temperature occurred when they laughed. The decrease was most dramatic in the nose dropping as much as 2.0 °C in 2 min. The response was evident in infants older than 4 months. These results suggest that a joyful emotion could be associated with a drop in facial skin temperature, which had been considered only as a sign of an unpleasant emotion. This response is developmentally controlled.

Uniform Distribution of Skin-Temperature Increase After Different Regional-Anesthesia Techniques of the Lower Extremity

Skin-temperature increase is a reliable but late indicator of success during regional-anesthesia techniques. The goal of this study is to determine the distribution of skin-temperature changes during different regional techniques. Does skin temperature increase in the whole area innervated by the blocked neural structures or only in certain regions within this area with the capability to react preferentially to sympathetic block (i.e., vessel-rich skin)? Although onset time may vary between different regional-anesthetic techniques, we hypothesized that the distribution of skin warming is equal. Skin temperature was assessed continuously by infrared thermography in 24 patients who received either combined femoral-nerve and sciatic-nerve block, epidural anesthesia, or spinal anesthesia. Apart from differences in time of onset, no differential spatial distribution of skin-temperature changes could be detected. The earliest and greatest rise of skin temperature occurred at the great toe (10.6 degrees C +/- 0.4 degrees C), became smaller proximally, and was negligible above the ankles, irrespective of the type and extent of block. Video-thermography revealed that cold blood flows through subcutaneous veins immediately after onset of sympathetic block and initially decreases skin temperature (0.6 degrees C +/- 0.3 degrees C) during onset of spinal anesthesia. Irrespective of the applied regional-anesthetic technique, skin-temperature changes are more pronounced distally. Thermography prevents false measurements of skin temperature above subcutaneous veins and displays flow of cold blood as the mechanism of initial skin-temperature drop after regional anesthesia. Measurements of skin-temperature increase cannot be used to evaluate the extent of analgesia or sympathetic block.

The Changes of Skin Temperature on Hands and Feet During and after T3 Sympathicotomy for Palmar Hyperhidrosis

Unilateral thoracic sympathectomy in patients with palmar hyperhidrosis causes a skin temperature drop in the contralateral hand. A cross-inhibitory effect by the post-ganglionic neurons innervating hands is postulated as a mechanism of contralateral vasoconstriction. The purpose of our study was to evaluate whether this cross-inhibitory effect also occurs in the feet. Twenty patients scheduled for thoracoscopic sympathicotomy due to palmar hyperhidosis were studied. Right T3 sympathicotomy was performed first, followed by left T3 sympathicotomy. The thenar skin temperatures of both hands and feet were continuously monitored using a thermometer and recorded before induction of anesthesia, during the operation, 4 hr after and 1 week later. Following right T3 sympathicotomy, the skin temperature of the ipsilateral hand gradually increased, however the skin temperature of the contralateral hand gradually decreased. Immediately after bilateral sympathicotomy, the skin temperature differences between hands and feet increased, but these differences decreased 1 week later. Our results show that cross-inhibitory control may exist in feet as well as in the contralateral hand. Thus, the release of cross-inhibitory control following T3 sympathicotomy results in vasoconstriction and decrease of skin temperature on the contralateral hand and feet. One week later, however, the temperature balance on hands and feet recovers.

Fatigue estimation of visual display terminal (VDT) workers by physiological data--preliminary study of a new computer program for VDT work analysis

The methods for assessing VDT workload based on individual capabilities are necessary to evaluate general fatigue by VDT work. We have developed a new computer program for assessing data entry performance of each individual. Four healthy male volunteers conducted a data entry task at their own pace using this program under a controlled environment. They performed the task for 30 minutes twice with 10 minutes rest between them. As a result, the average number of inputs was 133.2 characters/min in the first task and 129.1 characters/min after taking the rest. The error rate was 8.6% and 10.6% in each task. This program was useful to evaluate their data entry performance. We also reported our concern with a drop in nasal skin temperature that was observed during these VDT tasks.

Systemic Effects of Low-Intensity Laser Irradiation on Skin Microcirculation in Patients with Diabetic Microangiopathy

Low-intensity laser irradiation has been shown to induce wound healing in conditions of reduced microcirculation, which is in part explained by systemic effects. We therefore investigated such a potential systemic effect of low-intensity laser irradiation on skin blood circulation in patients with diabetic microangiopathy. Patients with diabetic microangiopathy were randomized to receive either a single helium–neon (HeNe, 632.8 nm) low-intensity laser irradiation with a dose of 30 J/cm 2 or a sham irradiation over the forefoot region in a double-blind, placebo-controlled clinical study. Skin blood circulation by means of temperature recordings over forefoot regions was detected by infrared thermography. Following a single transcutaneous low-intensity laser irradiation, a rise in skin temperature in both feet of the subjects in the laser group was noted, whereas in both feet of the subjects in the placebo group a drop in skin temperature occurred. The baseline-adjusted skin temperature 15 min after the end of the irradiation was significantly higher in the laser-treated forefeet compared to the placebo-“treated” forefeet ( p < 0.0001); the baseline-adjusted difference in the temperature was 1.94 ± 0.35°C. Simultaneously, the baseline-adjusted skin temperature was significantly higher in the laser-untreated forefeet compared to the placebo-“untreated” forefeet ( P < 0.0001); the baseline-adjusted difference was 1.70 ± 0.33°C. Our data show a significant increase in skin circulation due to athermic laser irradiation in patients with diabetic microangiopathy and point to the possibility of inducing systemic effects.

The effect of gel burns dressings on skin temperature

Objectives: This study was designed to investigate the effect on skin temperature of different methods of use of a hydrogel dressing. Methods: Twelve volunteers had temperature measured under a hydrogel...

Assessment of phasic work stress using autonomic indices

The present paper concerns the assessment of phasic work stress using autonomic indices such as skin temperature, respiratory measures, and heart rate, blood pressure, and their variabilities. A physiological model of the autonomic regulation of the cardiovascular and respiratory systems is also introduced in order to simulate and interpret the changes in these indices. Two experiments were conducted to investigate high tension and monotony as two types of mental work stress. A tracking task was used to induce high-tension work stress with and without an instruction intended to induce additional emotional stress. The same tracking task was repeated 12 times to simulate monotonous work stress. Fifty healthy adults participated in each experiment. Many physiological measures showed task-dependent changes in the high-tension experiment and at the beginning of the monotonous stress condition. These changes were explained by sympathetic activation, parasympathetic withdrawal, and respiratory rate activation. An additional drop in skin temperature and an additional HR increase were caused by the stressful instruction, which may reflect an emotional strain and can be explained by sympathetic activation. Furthermore, the mid-frequency component (approx. 0.1 Hz) of respiration and respiratory instability showed an obvious increase during the course of the monotonous stress experiment, which may reflect boredom and disgust. It was concluded that multidimensional recordings of autonomic measures that can be obtained during work without extra load on the worker would be helpful to assess different types of phasic work stress. The proposed model was further shown to be able to detect periods of stress in a complex work environment.

Validation of a model for prediction of skin temperatures in footwear.

A model for foot skin temperature prediction was evaluated on the basis of 2 experiments on subjects at various environmental temperatures (light seated manual work at -10.7 degrees C (Study 1), and a short walking period in combination with standing and sitting at +2.8 degrees C, -11.8 degrees C and -24.6 degrees C (Study 2), with boots of 3 insulation levels. Insulation of the footwear was measured on a thermal foot model. Predicted and measured data showed a relatively good correlation (r = 0.87) at the 2 colder conditions in Study 2. The environmental temperature of 2.8 degrees C was not low enough at the chosen activity for a considerable foot skin temperature drop. In Study 1 the predicted temperature stayed higher for the whole exposure period and the difference between the predicted and the measured foot skin temperatures grew proportionally with time, while subsequent warm-up curves at room temperature were almost parallel. In Study 1 the correlation was 0.95. However, the paired t-test showed usually significant differences between measured and predicted foot skin temperatures. The insulation values from thermal foot measurements can be used in the model calculations. Lotens' foot model is lacking activity as direct input parameter, however, the blood flow is used instead (effect through Tcore). The Lotens foot model can give reasonable foot skin temperature values if the model limitations are considered. Due to the lack of activity level input, it will be difficult to make any good estimation of foot skin temperature during intermittent exercise. The rate of the foot temperature recovery after cold exposure was somewhat overestimated in the model--the warm-up of the feet of the subjects started later and was slower in the beginning of the warm-up than in the prediction. It could be useful to develop the model further by taking into consideration various wetness and activity levels.