Regional Skin Temperature Research Articles

Residual limb temperature study with Pe-Lite liner in traumatic transtibial amputees

Interventions to alleviate thermal discomfort, a common complaint in amputees, are typically chosen based on residual limb skin temperature while wearing prosthesis; however, residual limb skin temperature while outside of the prosthesis has received less attention. The purpose of this study was to investigate the localized and regional skin temperature over the transtibial residual limb (TRL) when the prosthesis was removed. The present study documents the temperature variations in a traumatic below knee amputee with Pe-Lite liner. This study included eight unilateral transtibial amputees. Over the residual limb, twelve sites were marked in four columns (anterior, posterior, medial, and lateral) and three rows (proximal, middle, and distal). The temperature of the residual limb was measured with an infrared thermometer both in a relaxed state and after 30 minutes of activity with a Pe-Lite liner. The current study found a rise in temperature on the anterior side (36.30⁰C to 36.44⁰C), posterior side (36.36⁰C to 36.50⁰C), medial side (36.34⁰C to 36.40⁰C), and lateral side (36.35⁰C to 36.45⁰C). The temperature distribution over the TRL was found to be unequal, with significantly higher and lower temperatures on its posterior and medial sides, respectively.

Relationship between aerobic fitness and lower limb skin temperature during cycling exercise testing among well-trained athletes and nonathletes: a cross-sectional study

BackgroundDuring prolonged physical exercise, the skin plays an important role in thermoregulation by dissipating heat to maintain core temperature. Moreover, thermal variation may be influenced by the physical fitness level of an individual. The aim of the present study was to determine the relationship between aerobic fitness and lower limb skin temperature during graded cycling exercise testing in well-trained athletes and nonathletes. MethodsTwelve trained athletes (mean ± SD maximal oxygen consumption [VO2max], 52.44 ± 4.5 ml/kg/min) and 12 nonathletes (VO2max, 36.95 ± 4.9 ml/kg/min) participated in this study. The regional skin temperature over the lower limbs was monitored continuously during incremental exercise testing using a thermal camera, and cardio-respiratory parameters were assessed and recorded using a metabolic analyzer (K5, COSMED, Rome, Italy). ResultsThe mean skin temperature of athletes at a high intensity of exercise was 27.23 ± 0.3 °C while that of nonathletes was 29.03 ± 0.44 °C, a difference that was statistically significant (p < 0.05). A negative correlation was observed between skin temperature and cardiovascular parameters (VO2max and heart rate) in athletes, while no such correlation was found among nonathletes. ConclusionThe present study demonstrated a negative correlation between oxygen consumption and lower limb skin temperature in athletes, while the correlation was poor in nonathletes. This suggests that physical fitness level may influence the pattern of alterations in lower limb skin temperature, which supports the hypothesis that athletes exhibit better heat dissipation mechanisms than nonathletes.

Attention to body parts prompts thermoregulatory reactions in Body Integrity Dysphoria

In healthy subjects, the transient perturbation of body part ownership is accompanied by regional skin temperature decrease. This observation leaves an open question about a possible body part-specific thermoregulatory response in pathological conditions, in which the sense of ownership over that body part is altered. For instance, Body Integrity Dysphoria (BID), a poorly understood neuropsychiatric disorder, is characterised by the non-acceptance of one or more of one's extremities. This unsettling feeling pervasively captures the individuals' attention towards the unwanted limb. Previous studies characterised BID in terms of absent ownership feeling with preserved ownership judgment. We explored for the first time whether this altered feeling is also associated with a specific thermoregulatory response. We recorded thermal image sequences of circumscribed regions of the limbs' skin in seven individuals with BID desiring to remove one leg while they were invited to focus their attention toward one particular limb (arm or leg). Their event-related thermoregulatory pattern was compared to a group of healthy matched controls. In individuals with BID but not in control persons, we found a bilateral decrease in leg temperature when focusing their attention on either the unwanted or accepted leg. The event-related thermoregulatory response for both upper limbs was similar between individuals with BID and healthy controls. Our results suggest that the alteration of the sense of body ownership in neuropsychiatric conditions such as BID may critically rest on specific event-related thermoregulatory patterns in response to modulation of attention to body parts.

Investigation of Localized Skin Temperature Distribution Across the Transtibial Residual Limb.

Interventions to resolve thermal discomfort as a common complaint in amputees are usually chosen based on the residual limb skin temperature while wearing prosthesis; whereas, less attention has been paid to residual limb skin temperature while outside of the prosthesis. The objective of this study was to explore the localized and regional skin temperature over the transtibial residual limb (TRL) while outside of the prosthesis. Eight unilateral transtibial adults with traumatic amputation were enrolled in this cross-sectional study. Participants sat to remove their prostheses and rested for 30 minutes. Twelve sites were marked circumferentially in four columns (anterolateral, anteromedial, posteromedial, and posterolateral) and longitudinally in three rows (proximal, middle, and distal) over the residual limb and used for attachment of analog thermistors. Skin temperature was recorded and compared for 11 minutes. Furthermore, the relationship of skin temperature with participants' demographic and clinical characteristics was explored. The whole temperature of the TRL was 27.73 (SD=0.83)°C. There was a significant difference in skin temperature between anterior and posterior columns. Likewise, the distal row was significantly different from the proximal and middle rows. The mean temperature at the middle and distal zones of the anteromedial column had the highest and lowest skin temperatures (29.8 and 26.3°C, p<0.05), respectively. The mean temperature of the whole TRL had no significant relationships (p>0.05) with participants' demographic and clinical characteristics. An unequal distribution of temperature over the TRL was found with significantly higher and lower temperatures at its anterior column and distal row, respectively. This temperature pattern should be considered for thermoregulation strategies. Further investigation of the residual limb temperature with and without prosthesis, while considering muscles thickness and blood perfusion rate is warranted.

Validation of new method for predicting human skin temperatures during cold exposure: The Cold Weather Ensemble Decision Aid (CoWEDA)

Abstract Purpose The accuracy of the US Army's Cold Weather Ensemble Decision Aid (CoWEDA) was assessed for the prediction of human skin temperatures while exposed to cold environmental conditions. Methods Data from four laboratory cold exposure studies were combined to examine skin temperature responses based on environment, clothing, and activities. This combined dataset included a total of 23 volunteers exposed to cold conditions between −40 and 0 °C during rest and moderate treadmill walking. Observed measures of mean skin temperature and regional skin temperatures were compared to modeled predictions, where predictive accuracy and precision were evaluated by the bias, mean absolute error (MAE), and root mean square error (RMSE). Results Skin temperature predictions were within an acceptable range of accuracy when compared to observed values (bias, −0.71 ± 2.21 °C; MAE, 1.85 ± 1.75 °C; and RMSE, 2.28 ± 1.54 °C) across all conditions. An acceptable level of predictive accuracy was also observed for finger (bias, −0.98 ± 2.50 °C; MAE, 2.68 ± 2.09 °C; RMSE, 2.68 ± 1.71 °C) and mean skin temperatures (bias, −0.03 ± 1.25 °C; MAE, 1.06 ± 0.65 °C; RMSE, 1.25 ± 0.68 °C). Conclusion The CoWEDA acceptably predicts skin temperatures while at rest and exercise during cold exposure in controlled laboratory conditions.

A preliminary investigation about the observation of regional skin temperatures following cumulative training loads in triathletes during training camp.

There are controversial results in the literature concerning the concept that cumulative training load could affect basal skin temperature in the days following training sessions. The objective was to measure skin temperature in triathletes during a training camp with cumulative training load. Ten male recreational triathletes involved in a training camp underwent measurements of perception of pain and fatigue (visual analogue scale), skin temperature (infrared thermography), and jump performance (counter movement jump test) before, one day, and two days after the beginning of the training camp. All measurements were performed before the breakfast. Jump height did not differ between the days (p > 0.05). Fatigue perception increased after the first and second day of training for most of the body regions (p < 0.05). Pain perception increased after two days of training (p < 0.05). Mean and maximum skin temperature increased after the second day of training for most of the body regions (p < 0.05). Skin temperature in some body regions was directly related with muscle mass, weekly training volume, and inverse related with fatigue perception (p < 0.05 and R2 > 0.4). Possible explanations of these results in comparison with previous studies may include the influence of control of the intrinsic and extrinsic factors related to the skin temperature assessment (for instance, the time of the day, lack of muscle soreness, daily activity control). These preliminary results have important implication on the use of skin basal temperature data to monitor exercise recovery, which claims for further research.

Skin Temperatures in Females Wearing a 2 mm Wetsuit during Surfing.

The aim of this investigation was to examine regional skin temperatures in recreational female surfers’ wearing a 2 mm thick neoprene wetsuit while surfing and to compare these results to previously published data collected in males participating in an identical study. Female surfers (n = 27) engaged in surfing for at least 40 min while wearing a commercially available 2 mm full wetsuit. Skin temperature of eight different anatomical locations were measured with wireless iButton thermal sensors. Regional skin temperatures significantly differed (p < 0.001) across almost all anatomical regions. Furthermore, regional skin temperatures significantly decreased across time at all skin regions throughout an average surfing session (p < 0.001). The greatest reduction in skin temperature was observed in the lower leg (−5.4 °C). Females in the current study exhibited a significantly greater skin temperature decrease in the lower back (−15.2% vs. −10.8%, p = 0.022) and lower arm (−13.6% vs. −10.8%, p < 0.001) when compared to previous data published in males. Overall, results of the current study are consistent with data previously published on male recreational surfers. However, the current study provides preliminary evidence that the magnitude of change in skin temperature may differ between male and female recreational surfers at some anatomical locations.

Characterisation of regional skin temperatures in recreational surfers wearing a 2-mm wetsuit

The purpose of this study was to investigate skin temperatures across surfers’ bodies while wearing a wetsuit during recreational surfing. Forty-six male recreational surfers participated in this study. Participants were instrumented with eight wireless iButton thermal sensors for the measurement of skin temperature, a Polar RCX5 heart rate monitor and a 2-mm full wetsuit. Following instrumentation, participants were instructed to engage in recreational surfing activities as normal. Significant differences (p < 0.001) in skin temperature (Tsk) were found across the body while wearing a wetsuit during recreational surfing. In addition, regional skin temperature changed across the session for several regions of the body (p < 0.001), and the magnitude of these changes varied significantly between regions. We show for the first time that significant differences exist in skin temperature across the body while wearing a wetsuit during a typical recreational surfing session. These findings may have implications for future wetsuit design.Practitioner Summary: This study investigated the impact of wearing a wetsuit during recreational surfing on regional skin temperatures. Results from this study suggest that skin temperatures differ significantly across the body while wearing a 2-mm wetsuit during recreational surfing. These findings may have implications for future wetsuit design.

Modelling hand skin temperature in relation to body composition

Skin temperature is a challenging parameter to predict due to the complex interaction of physical and physiological variations. Previous studies concerning the correlation of regional physiological characteristics and body composition showed that obese people have higher hand skin temperature compared to the normal weight people. To predict hand skin temperature in a different environment, a two-node hand thermophysiological model was developed and validated with published experimental data. In addition, a sensitivity analysis was performed which showed that the variations in skin blood flow and blood temperature are most influential on hand skin temperature. The hand model was applied to simulate the hand skin temperature of the obese and normal weight subgroup in different ambient conditions. Higher skin blood flow and blood temperature were used in the simulation of obese people. The results showed a good agreement with experimental data from the literature, with the maximum difference of 0.31°C. If the difference between blood flow and blood temperature of obese and normal weight people was not taken into account, the hand skin temperature of obese people was predicted with an average deviation of 1.42°C. In conclusion, when modelling hand skin temperatures, it should be considered that regional skin temperature distribution differs in obese and normal weight people.

Experimental study on the variations in human skin temperature under simulated weightlessness

To study the variations in skin temperature in weightlessness, the skin temperatures of 6 male volunteers were measured under simulated weightlessness by head down bed rest (HDBR) experiments. The effects of the air temperature, relative humidity and air speed on the mean skin temperature were scrutinized, and the regional skin temperatures of the subjects under comfortable conditions were investigated. The results showed that the mean skin temperature increased with the air temperature both before and after HDBR in low and neutral air temperatures and that the mean skin temperature was found to be higher before HDBR. However, a higher mean skin temperature was observed after HDBR when the air temperature was high. Moreover, the mean skin temperature in low and neutral air temperatures was found to increase with the relative humidity both before and after HDBR, and a higher mean skin temperature was also observed before HDBR. Additionally, a negative correlation between the mean skin temperature and air speed was observed both before and after HDBR. However, different patterns of the mean skin temperature were observed when the environment changed from low air temperature and humidity to a neutral environment and finally to a high air temperature and humidity. Finally, the regional skin temperature after HDBR showed a different distribution compared with that before HDBR, such as a higher skin temperature in the thorax, forehead and back and a lower skin temperature in the thigh, calf and hand. This indicated that the skin temperature distribution changed greatly under simulated weightlessness by HDBR, which might suggest an altered thermal regulatory mechanism in humans experiencing weightlessness.

Individualising the exposure of −110 °C whole body cryotherapy: The effects of sex and body composition

The purpose of this study was to investigate the effects of whole body cryotherapy (WBC) on a range of thermoregulatory measures. We also sought to examine the influence of sex and body composition. A convenience sample of 18 healthy participants (10 males and 8 females) (27±6yr) volunteered for this study. Temperature (core, tympanic, skin and mean body), heart rate, blood pressure, and thermal comfort and sensation were recorded pre- and post- (immediately and every 5min until 35min post) exposure to a single bout of WBC (30s at −60°C, 150s at 110°C). Anthropometric data (height, weight, body surface area, body mass index, fat mass and fat free mass) were also recorded. No significant differences in temperature (core, tympanic, skin and mean body), heart rate, blood pressure, or thermal comfort / sensation were observed between male and females at baseline. Immediately post WBC mean body (male:31.9±0.8°C; female:31.0±0.9°C; ∆ mean body temperature:0.9±0.1°C; P≤0.05, d=0.64) and mean skin (male:22.1±2.2°C; female:19.6±2.8°C; ∆ mean skin temperature:−2.5±0.6°C; d=0.99, P≤0.05) temperature was significantly different between sexes. Sex differences were also observed in regional skin temperature (male thigh, 20.8±1.1°C; female thigh, 16.7±1.1°C, ∆ mean thigh skin temperature:−4.1°C; d=3.72; male calf, 20.5±1.1°C; female calf, 18.2±1°C, ∆ mean calf skin temperature:−2.3±0.1°C; d=3.61; male arm, 21.7±1°C; female arm, 19±0.4°C, ∆ mean arm skin temperature: −2.7±0.3°C; d=3.54; P≤0.05). Mean arterial pressure was significantly different over time (P≤0.001) and between sexes (male 0mins:94±10mmHg; female 0mins:85±7mmHg; male 35mins:88±7mmHg; female 35mins:80±6mmHg; P≤0.05). Combined data set indicated a strong negative relationship between skin temperature and body fat percentage 35min’ post WBC (r=−0.749, P≤0.001) and for core temperature and body mass index in males only (r=0.726, P≤0.05) immediately after WBC. There were no significant differences between sexes in any other variables (heart rate, tympanic and perceptual variables). We observed sex differences in mean skin and mean body temperature following exposure to whole body cryotherapy. In an attempt to optimise treatment, these differences should be taken into account if whole body cryotherapy is prescribed.

Regional Skin Temperature Responses to Warm vs. Cold in Healthy Lean and Obese Young Men

Regional Skin Temperature Responses to Warm vs. Cold in Healthy Lean and Obese Young Men

Regional Skin Temperature Response to Moderate Aerobic Exercise Measured by Infrared Thermography.

Background:Infrared thermography (IRT) does not require contact with the skin, and it is a convenient, reliable and non-invasive technique that can be used for monitoring the skin temperature (TSK).Objectives:The aim of this study was to monitor the variations in the regional TSK during exercise on 28 regions of interest (ROIs) (forehead, face, chest, abdomen, back, lumbar, anterior and posterior neck, and posterior and anterior views of the right and left hands, forearms, upper arms, thighs, and legs) with IRT.Patients and Methods:12 physically active young males were monitored with IRT during the following three phases: a) 30 minutes before exercise b) while performing one hour of moderate intensity exercise on a treadmill at 60% of the VO2max, and c) 60 minutes after exercise.Results:During pre-exercise, all TSK reached a steady-state (P ≤ 0.05), which ensured adequate thermal stabilisation. At the beginning of exercise, there was a significant reduction in the TSK in most ROIs after 10 minutes of activity, except for the lower limbs (legs and thighs). After one hour of recovery, in the anterior view of the hands and thighs and in the posterior view of the legs, there were significant increases in the TSK compared to pre-exercise.Conclusions:There were significant distinctions in the skin temperature distribution during exercise according to the activity of the area under consideration during exercise, which may be important in the development of physiological models and heat flux analyses for different purposes.

Body temperature mapping in critically ill newborn infants nursed under radiant warmers during intensive care.

The objectives of this study were to assess (i) the agreement between servo-control temperature (Tfeedback) and rectal temperature (Tre) and (ii) the distribution of regional skin temperatures (Tsk) of neonates nursed under a radiant warmer (RW) in a neonatal intensive care unit. An observational study of 13 neonates nursed under a RW device set to servo-control mode (Tfeedback set-point: 36.5 °C) who were monitored for Tfeedback, Tre and Tsk at six sites for a period of 105 min. Mean bias for Tfeedback relative to Tre was +0.01 °C, but 95% limits of agreement were ±0.99 °C, and only 66% of Tfeedback values were within the acceptable limits determined a priori (±0.5 °C). Tfeedback was maintained within a range of 1.4 °C (35.9 to 37.3 °C), whereas the range observed for regional skin temperatures spanned from 9.5 °C (27.3 to 36.8 °C; foot) to 4.8 °C (33.1 to 37.9 °C; chest). Although Tfeedback is maintained within narrow limits, the level of agreement with Tre is poor. In addition, large fluctuations in regional skin temperatures occur with a consistent caudal-to-rostral temperature gradient, irrespective of Tfeedback.

PMV model is insufficient to capture subjective thermal response from Indians

A controlled laboratory experiment was carried out on forty Indian male college students for evaluating the effect of indoor thermal environment on occupants' response and thermal comfort. During experiment, indoor temperature varied from 21 °C to 33 °C, and the variables like relative humidity, airflow, air temperature and radiant temperature were recorded along with subject's physiological parameters (skin (Tsk) and oral temperature (Tc)) and subjective thermal sensation responses (TSV). From Tsk and Tc, body temperature (Tb) was evaluated. Subjective Thermal Sensation Vote (TSV) was recorded using ASHRAE 7-point scale. In PMV model, Fanger's Tsk equation was used to accommodate adaptive response. Stepwise regression analysis result showed Tb was better predictor of TSV than Tsk and Tc. Regional skin temperature response, suppressed sweating without dipping, lower sweating threshold temperature and higher cutaneous threshold for sweating were observed as thermal adaptive responses. These adaptive responses cannot be considered in PMV model. To incorporate subjective adaptive response, mean skin temperature (Tsk) is considered in dry heat loss calculation. Along with these, PMV-model and other two methodologies are adopted to calculate PMV values and results are compared. However, recent literature is limited to measure the sweat rate in Indians and consideration of constant Ersw in PMV model needs to be corrected. Using measured Tsk in PMV model (Method1), thermal comfort zone corresponding to 0.5 ≤ PMV ≤ 0.5 was evaluated as (22.46–25.41) °C with neutral temperature of 23.91 °C, similarly while using TSV response, wider comfort zone was estimated as (23.25–26.32) °C with neutral temperature at 24.83 °C, which was further increased to with TSV-PPDnew relation. It was observed that PMV-model overestimated the actual thermal response. Interestingly, these subjects were found to be less sensitive to hot but more sensitive to cold. A new TSV-PPD relation (PPDnew) was obtained from the population distribution of TSV response with an asymmetric distribution of hot-cold thermal sensation response from Indians. The calculations of human thermal stress according to steady state energy balance models used on PMV model seem to be inadequate to evaluate human thermal sensation of Indians. Relevance to industryThe purpose of this paper is to estimate thermal comfort zone and optimum temperature for Indians. It also highlights that PMV model seems to be inadequate to evaluate subjective thermal perception in Indians. These results can be used in feedback control of HVAC systems in residential and industrial buildings.

Physiological and subjective thermal response from Indians

A controlled laboratory experiment was carried out on forty Indian male college students for evaluating the effect of indoor thermal environment on occupants' response and thermal comfort. During experiment, indoor temperature varied from 21 °C to 33 °C, and the variables like relative humidity, airflow, air temperature and radiant temperature were recorded along with skin (Tsk) and oral temperature (Tcore) from the subjects. From Tsk and Tc, body temperature (Tb) was evaluated. Subjective Thermal Sensation Vote (TSV) was recorded using ASHRAE 7-point scale. In PMV model, Fanger's Tsk equation was used to accommodate adaptive response. Stepwise regression analysis result showed Tb was better predictor of TSV than Tsk and Tcore. Regional skin temperature response, lower sweat threshold temperature with no dipping sweat and higher cutaneous sweating threshold temperature were observed as thermal adaptive responses. Using PMV model, thermal comfort zone was evaluated as (22.46–25.41) °C with neutral temperature of 23.91 °C, whereas using TSV response, wider comfort zone was estimated as (23.25–26.32) °C with neutral temperature at 24.83 °C. It was observed that PMV-model overestimated the actual thermal response. Interestingly, these subjects were found to be less sensitive to hot but more sensitive to cold. A new TSV-PPD relation (PPDnew) was obtained with an asymmetric distribution of hot-cold thermal sensation response in Indians.

Accidental overheating of a newborn under an infant radiant warmer: a lesson for future use

A fully functional radiant warmer induced rapid and continuous increases in regional skin temperatures, heart rate, mean arterial blood pressure and respiratory rate in a newborn patient without corrective action. We report this case of passive overheating to create awareness of the risks associated with regulating radiant heat output based upon a single servo-controlled temperature.

Body mapping of thermoregulatory and perceptual responses of males and females running in the cold

Thermoregulatory parameters during exercise are typically reported as global responses (Tcore and mean Tsk). In contrast, this study investigated regional skin temperatures (Tsk) over the body, in relation to regional skinfold thickness and regional perceptual responses for both sexes using a body-mapping approach. Nine males and nine females, of equivalent fitness, minimally clothed, ran for 40min at 70% V̇O2max in a 10°C, 50%rh, 2.8ms−1 air velocity environment. Tsk was recorded by infrared thermography and processed to obtain population-averaged body maps. Rectal temperature and heart rate were monitored continuously throughout the running trial. Skinfold thickness was obtained for 24 sites and thermal sensation votes for 11 body regions.Males and females had similar rectal temperature, heart rate and regional sensations. Whole-body maps of Tsk highlighted the significantly lower regional Tsk for females (−1.6°C overall, p<0.01). However, the distribution of Tsk across the body was similar between sexes and this was not correlated with the distribution of skinfold thickness, except for the anterior torso. On the other hand, regional thermal sensation votes across the body were correlated with Tsk distribution during exercise (females: r=0.61, males: r=0.73, p<0.05), but not at rest.Our thermographic results demonstrate the similar Tsk distribution for active males and females during submaximal running in the cold, though shifted to a lower mean value for females. This Tsk distribution was associated with regional sensations but not with local fat thickness. The described body-mapping approach can have implications in physiological modelling and clothing design.

운동시 피부온의 변화에 대한 서모그래피 활용 분석

The purpose of this study was to investigate the variation of regional skin temperature with thermography during exercise. Seven men completed 82-min trials which consisted of rest, exercise of <TEX>$VO_2$</TEX> max 60% and recovery period at <TEX>$30{\pm}0.5^{\circ}C$</TEX> and <TEX>$60{\pm}5%RH$</TEX>. Changes in skin temperature due to physical activity varied, depending region of the body. The skin temperature of the chest was significantly lowered and that of the back was significantly increased after exercise period(p < 0.05). There were significant negative relationship between the skin temperature of the chest and thermal comfort sensation, and positive relationship between skin temperature of the back and thermal comfort sensation(p < 0.05). It would be better to keep the chest warm, and the back cool during exercise. The skin temperature changed differently on body site due to exercise, and it was influenced by blood flow, sweating and air movement. This study would be meaningful in that the change of regional skin temperature during exercise was investigated consecutively with thermography. In further study, it would be more realistic to measure physiological response with functional sportswear which applies different functional fabric based on skin temperature.

Regional Sweating Differs Between Elite American Football Linemen and Backs Independently of Metabolic Heat Production

Evaporative heat loss via sweating is the primary heat dissipation avenue during exercise, particularly in a hot environment. In typical summer football training camps, larger linemen have significantly greater elevations in core temperature than smaller backs. However it is unclear if differences in sweat production are responsible for these higher core temperatures. PURPOSE: Investigate whether differences in local and whole-body sweat rates between football linemen and backs exist independently of differences in metabolic heat production. METHODS: 12 NCAA Division 1 American football players (6 linemen [mass: 141.6±6.5 kg; BSA: 2.67±0.08 m2] and 6 backs [mass: 88.1±13.4 kg; BSA: 2.11±0.19 m2]) exercised at a fixed metabolic heat production of 350 W/m2 for 60-min in a climatic chamber (Tdb: 32.4±1.0°C; Twb: 26.3±0.6°C; Vair: 0.9±0.1 m/s). Core temperature (Tcore) and mean skin temperature (Tsk) were measured throughout. Local sweat rates (LSR) on the head, arm, upper back, lower back and chest were measured after 10, 30 and 50 min of exercise, and whole-body sweat loss was measured using changes in pre and postexercise body weight. RESULTS: Whole-body sweat rate was identical in linemen (8.6±1.8 g/m2/min) and backs (8.6±1.4 g/m2/min); however LSR was significantly greater (P<0.05) in linemen at 4 of 5 sites (head, arm, upper back and chest) after 10-min; at 2 of 5 sites (arm and chest) after 30-min; but no differences were observed for LSR between linemen and backs after 50-min. At the end of exercise, Tcore was significantly greater (P=0.025) in linemen (38.48±0.39°C) relative to backs (38.01±0.24°C). Mean Tsk throughout was similar in linemen (35.34±0.48°C) compared to backs (35.21±0.25°C); however when accounting for differences in starting Tsk, linemen (1.71±0.23°C) had a greater change (P<0.001) than backs (0.82±0.26°C). CONCLUSION: Despite identical whole-body sweating at a fixed heat production per unit surface area, upper body LSR in linemen was greater during the early stages of exercise and presumably lower elsewhere. More profuse upper body sweating in linemen is attributed to greater changes in regional skin temperature. This potentially leads to a greater amount of non-evaporated sweat dripping off the body, a lower whole-body evaporative efficiency and greater elevations in core temperature.