Rise In Skin Temperature Research Articles

Effects of Pre-Cooling on Thermophysiological Responses in Elite Eventing Horses.

Simple SummaryHorses have a high metabolic capacity for exercise, producing a great deal of heat, and have a small surface area for heat loss. Under limited circumstances, the regulation of heat loss (i.e., across the respiratory tract and by the evaporation of sweat) means heat build-up in the body is reduced. Thermoregulation can be assisted by cooling the horses down to safely perform exercise in thermally challenging environments. The present study showed that pre-cooling (i.e., cooling between the warm-up and exercise performance) slightly reduced the rise in rectal, shoulder and rump skin temperatures of ten international eventing horses during moderately intense canter training in moderate environmental conditions. During the canter training, heart rate, sweat rate and sweat composition were unaffected by pre-cooling. The pre-cooling strategy chosen here was cold-water rinsing for a short period of time (~8 min). Considering the limited time and space at equestrian events, such a pre-cooling strategy could easily be implemented. Reducing heat strain by pre-cooling may potentially improve equine welfare during events.In this study, we examined the effects of pre-cooling on thermophysiological responses in horses exercising in moderate environmental conditions (average wet bulb globe temperature: 18.5 ± 3.8 °C). Ten international eventing horses performed moderate intensity canter training on two separate days, and were either pre-cooled with cold-water rinsing (5–9 °C for 8 ± 3 min; cooling) or were not pre-cooled (control). We determined velocity (V), heart rate (HR), rectal temperature (Tre,), shoulder and rump skin temperature (Tshoulder and Trump), plasma lactate concentration (LA), gross sweat loss (GSL), and local sweat rate (LSR), as well as sweat sodium, chloride and potassium concentrations. The effect of pre-cooling on Tre was dependent on time; after 20 min of exercise the effect was the largest (estimate: 0.990, 95% likelihood confidence intervals (95% CI): 0.987, 0.993) compared to the control condition, resulting in a lower median Tre of 0.3 °C. Skin temperature was also affected by pre-cooling compared to the control condition (Tshoulder: −3.30 °C, 95% CI: −3.739, −2.867; Trump: −2.31 °C, 95% CI: −2.661, −1.967). V, HR, LA, GSL, LSR and sweat composition were not affected by pre-cooling. In conclusion, pre-cooling by cold-water rinsing could increase the margin for heat storage, allowing a longer exercise time before a critical Tre is reached and, therefore, could potentially improve equine welfare during competition.

Effect of cooling strategies on overall performance of a hybrid personal cooling system incorporated with phase change materials (PCMs) and electric fans.

The effect of four cooling strategies on cooling performance of a hybrid personal cooling system (HPCS) incorporated with phase change materials (PCMs) and electric fans in a hot environment (i.e., Tair=36±0.5°C, RH=59±5%) was investigated. Twelve healthy young male participants underwent four 90-min trials comprising 70min walking and 20min resting periods. Cooling strategies adopted in this work were CON (control), PCM-control (PCMs were removed at the end of exercise), Fan-control (fans were switched OFF during the initial 20min) and PCM&Fan-control (fans were turned ON after 20min exercising and PCMs were removed after the 70-min exercise). Results demonstrated that the control of electric fans could suppress the mean skin temperature rise to 34.0°C by over 15min and also cut down the energy consumption of the HPCS from 15.6Wh to 12.1Wh over the entire 90-min trials. Thus, it is recommended that fans should be turned off at the beginning of hot exposure and switched on once participants felt warm. Our findings also showed that the removal of fully melted PCM packs from the HPCS could enhance the evaporative cooling effect brought about by air circulation. The removal of melted PCMs significantly reduced the physical load by 37.3% and ratings of perceived exertion (RPE) were decreased by 3.5-4.2 RPE units. This could also help quickly restore the PCM energy for future usage. In summary, cooling strategies demonstrated in this work could improve HPCS's overall cooling performance on workers while working in the studied hot environment.

Heatguard: An ultra-low-cost three-dimensional-printed sensor for skin temperature alert and reporting system.

A heatstroke is one of the most serious forms of heat injury and is classified as a medical emergency. It is characterized by an elevated core body temperature along with the failed body cooling mechanism in response to the sudden heat-up. People vulnerable to a heatstroke are children, elders and sports professionals. Previous efforts have emphasized exercise adjustments and post-treatments, such as environmental-based activity modification and cold-water immersion. However, the general public, especially elders, will have difficulty to conduct such adjustments by themselves. Moreover, few studies have been conducted on the early preventive measurement stage. A wearable three-dimensional-printed thermochromic device proposed here can warn the people of a sudden rise in skin temperature and can advise them to take quick action. Combined with the smartphone applications, for both the android and iPhone platform, the device is able to monitor real-time skin temperature and alerts the people who are vulnerable to a heatstroke. The three-dimensional printable resin developed can change color at a specific activation temperature. The device has undergone a series of performance tests in order to optimize the color transition rate and stability of color change. The accuracy of our device is compared to the conventional thermometer; the regression analysis shows the R2 value is 0.7599 and the average error is 1.3 °C. Future work will be to mitigate the surrounding lighting effects on the smartphone camera and further improve our device accuracy.

Good vibrations: Itch induction by whole body vibration exercise without the need of a pruritogen.

Mechanically induced itch is an important cofactor in many patients with chronic itch. However, studying mechanical itch in a controlled environment is challenging because it is difficult to evoke. We investigated the use of whole body vibration (WBV) exercise, a training method used for musculoskeletal rehabilitation, to experimentally evoke mechanical itch. Mild to severe itch ascending from the soles to the groins was evoked in 16 of 20 healthy participants. We observed a characteristic on/off itch crescendo pattern reflecting the alternating intervals of vibration and no vibration. Wheals or an angioedema was absent, and serum mast cell tryptase was not increased by the exercise. Participants described the evoked sensation primarily as "itching" with some nociceptive components. Itch intensity correlated with the intensity of a concomitant erythema (R=0.45, P=0.043) and with the rise in skin temperature (R=0.54, P=0.017). Hence, WBV can be used as an easily applicable, noninvasive, investigator- and user-friendly framework for studying mechanical itch. Moreover, WBV allows to "switch itch on and off" rapidly and to simultaneously study interactions between itch, skin blood flow and skin temperature.

Influence of ageing on human body blood flow and heat transfer: A detailed computational modelling study.

Ageing plays a fundamental role in arterial blood transport and heat transfer within a human body. The aim of this work is to provide a comprehensive methodology, based on biomechanical considerations, for modelling arterial flow and energy exchange mechanisms in the body accounting for age‐induced changes. The study outlines a framework for age‐related modifications within several interlinked subsystems, which include arterial stiffening, heart contractility variations, tissue volume and property changes, and thermoregulatory system deterioration. Some of the proposed age‐dependent governing equations are directly extrapolated from experimental data sets. The computational framework is demonstrated through numerical experiments, which show the impact of such age‐related changes on arterial blood pressure, local temperature distribution, and global body thermal response. The proposed numerical experiments show that the age‐related changes in arterial convection do not significantly affect the tissue temperature distribution. Results also highlight age‐related effects on the sweating mechanism, which lead to a significant reduction in heat dissipation and a subsequent rise in skin and core temperatures.

Patterns and reliability of children's skin temperature prior to and during sleep in the home setting.

The relationship between patterns of change in skin temperature and sleep is well recognized. In particular, there is a rapid rise in distal skin temperature (Tdistal) and slower rise in proximal skin temperature (Tproximal) prior to sleep onset. The difference between Tdistal and Tproximal is known as the distal-proximal gradient (DPG). Rise in DPG is known as a measure of distal vasodilation, which contributes to the drop in core body temperature (Tcore) that is important to sleep onset and maintenance. Patterns of change in skin temperature before and during sleep are reported for neonates, infants, adults and elderly, however they are not known for school aged children. Therefore, the current observational study aimed to determine the patterns and reliability of skin temperatures (Tskin) and DPG in relation to sleep of school aged children in their home settings. Participants (22 children, aged 6-12) completed the Children's Sleep Habits Questionnaire and used Thermochron iButtons and actigraphy for four school nights in their typical sleep settings. There were evident patterns of Tskin change before and during sleep. In particular, Tdistal was lower but rose more rapidly than Tproximal after reported bedtime and prior to sleep onset. This reflected a timely rise in DPG, and shows that distal vasodilation precedes sleep onset in school aged children. The measures of Tskin and sleep were practical for children in their home settings, and the observed patterns were consistent across consecutive school nights. Environmental and behavioural strategies that manage skin temperature before and during sleep should be explored for their potential as valuable components of treatment of childhood insomnia.

Improvement effects of a mixed extract of flowers of Pueraria thomsonii Benth. and peels of Citrus unshiu Markovich on postmenopausal symptoms of ovariectomized mice

BackgroundMenopausal hot flushes occur frequently in postmenopausal women. In the present study, we investigated a regulatory effect of a mixed extract of flowers of Pueraria thomsonii Benth. and peels of Citrus unshiu Markovich (PCE17), an extract of flowers of Pueraria thomsonii Benth. (PE), an extract of peels of Citrus unshiu Markovich (CE), a mixture of tectorigenin 7-O-xylosylglucoside, tectoridin, and tectorigenin (Tec, the active compounds of PE), and hesperidin (Hes, an active compound of CE) on menopausal hot flushes. MethodsWe examined the anti-hot flushes properties of PCE17, PE, CE, Tec, or Hes using a mouse model of ovariectomy-induced hot flushes. ResultsThe ovariectomy-induced rise in the tail skin temperature was significantly prevented by PCE17, PE, CE, Tec, or Hes. PCE17, PE, CE, Tec, or Hes significantly enhanced 5-HT levels and attenuated RANKL levels in the hypothalamus of ovariectomized (OVX) mice. Treatment with PCE17, PE, CE, Tec, or Hes significantly enhanced the levels of estrogen receptor (ER)-β, 5-HT1A, 5-HT2A, and tryptophan hydroxylase mRNA expression in the hypothalamus of OVX mice. PCE17, PE, or CE decreased follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, but did not increase estrogen levels in the serum of OVX mice. Tec or Hes decreased FSH or LH levels and increased estrogen levels. Treatment with PCE17, PE, CE, or Tec ameliorated vaginal atrophy in OVX mice. Finally, PCE17, PE, CE, Tec, or Hes significantly increased norepinephrine and dopamine levels in the hypothalamus of OVX mice. ConclusionThus, these results imply that PCE17 has protective effects against hot flushes.

Temperature rise induced by an annular focused transducer with a wide aperture angle in multi-layer tissue**Project supported by the National Key Research and Development Program, China (Grant No. 2016YFF0203000), the National Natural Science Foundation of China (Grant Nos. 11774167 and 61571222), the Fundamental Research Funds for the Central Universities, China (Grant No. 020414380001), the State Key Laboratory of Acoustics, Chinese

In order to improve the operability and accuracy of high-intensity focused ultrasound (HIFU), an annular focused transducer, whereby a B-ultrasound probe is placed in its center, is used to realize the real time monitoring and control of the treatment. In this paper, the spheroidal beam equation (SBE) was used to calculate the sound field by an annular focused transducer with a wide aperture angle to first derive the heat deposition and the Pennes equation was used to calculate the temperature field in multi-layer tissue. We studied the effect of different parameters on the temperature of the tissues. The result shows that the focal length has a significant influence on both maximum liver temperature rise and skin temperature rise, and both increase with the increase in the focal length. When the frequency increases, the temperature rise first undergoes a rapid increase before gradually reaching a maximum, and then finally decreasing. The temperature rise increases while the inner radius decreases or the sound pressure increases. By choosing suitable parameters, the proper temperature rise both on the target tissue and skin via an annular focused transducer with a wide aperture angle can be obtained.

Avoiding thermal injury during near-infrared photoimmunotherapy (NIR-PIT): the importance of NIR light power density.

Near-infrared photoimmunotherapy (NIR-PIT) is a newly-established cancer treatment which employs the combination of an antibody-photoabsorber conjugate (APC) and NIR light. When NIR light is absorbed by APC-bound tissues, a certain amount of heat is generated locally. For the most part this results in a subclinical rise in skin temperature, however, excessive light exposure may cause non-specific thermal damage. In this study, we investigated the potential for thermal damage caused by NIR-PIT by measuring surface temperature. Two sources of light, laser and light emitting diode (LED), were compared in a mouse tumor model. First, we found that the skin was heated rapidly by NIR light regardless of whether laser or LED light sources were used. Air cooling at the surface reduced the rise in temperature. There were no associations between the rise of skin temperature and tumor volume of the treated tumor, or APC concentration. Second, we investigated the extent of thermal damage to the skin at various light doses. We detected burn injuries 1 day after NIR-PIT, when the NIR light was at a power density higher than 600 mW/cm2. Successful treatments at lower power density could be achieved if the total light energy absorbed by the tumor was the same, i.e. by extending the duration of light exposure. In conclusion, this study demonstrates that thermal injury after NIR-PIT can be avoided by either employing a cooling system or by lowering the power density of the light source and prolonging the exposure time such that the total energy is constant. Thus, thermal damage is preventable side effect of NIR-PIT.

Study on different finite difference methods at skin interface for burn prediction in protective clothing evaluation

SummaryFor protective clothing evaluation by using the flame engulfment method, a skin burn injury model is required to predict burn degree of the covered skin. By applying finite difference methods, 2 numerical methods are compared. One is based on equivalent heat intensity; the other is based on the law of conservation of energy. In this study, skin temperature rise is compared between these 2 methods by using homogeneous skin properties as well as the analytical solutions. Differences between these 2 methods in application of measured heat exposure tests data are also explored. The results show that assuming equivalent heat intensity at the skin layer interfaces overestimates severity of burn injury. Burn injury time is sensitive to the investigated numerical methods, especially for third‐degree burns. The differences of the 2 methods can be reduced by optimization of the grid size using the test cases described in ASTM F1930. A detailed description of requirements regarding applicable numerical methods in future revisions of the relevant standards is recommended. The finite difference model applied in this paper can act as an effective tool to predict temperature distribution in the skin as well as predict burn injury for evaluation of thermal protective clothing.

Characterizing human skin blood flow regulation in response to different local skin temperature perturbations

Small nerve fibers regulate local skin blood flow in response to local thermal perturbations. Small nerve fiber function is difficult to assess with classical neurophysiological tests. In this study, a vasomotor response model in combination with a heating protocol was developed to quantitatively characterize the control mechanism of small nerve fibers in regulating skin blood flow in response to local thermal perturbation.The skin of healthy subjects' hand dorsum (n=8) was heated to 42°C with an infrared lamp, and then naturally cooled down. The distance between the lamp and the hand was set to three different levels in order to change the irradiation intensity on the skin and implement three different skin temperature rise rates (0.03°C/s, 0.02°C/s and 0.01°C/s). A laser Doppler imager (LDI) and a thermographic video camera recorded the temporal profile of the skin blood flow and the skin temperature, respectively.The relationship between the skin blood flow and the skin temperature was characterized by a vasomotor response model. The model fitted the skin blood flow response well with a variance accounted for (VAF) between 78% and 99%. The model parameters suggested a similar mechanism for the skin blood flow regulation with the thermal perturbations at 0.03°C/s and 0.02°C/s. But there was an accelerated skin vasoconstriction after a slow heating (0.01°C/s) (p-value<0.05). An attenuation of the skin vasodilation was also observed in four out of the seven subjects during the slow heating (0.01°C/s). Our method provides a promising way to quantitatively assess the function of small nerve fibers non-invasively and non-contact.

Treatment with an orally bioavailable prodrug of 17β-estradiol alleviates hot flushes without hormonal effects in the periphery.

Estrogen deprivation has a profound effect on the female brain. One of the most obvious examples of this condition is hot flushes. Although estrogens relieve these typical climacteric symptoms, many women do not want to take them owing to unwanted side-effects impacting, for example, the uterus, breast and blood. Therefore, there is a need for developing safer estrogen therapies. We show here that treatment with 10β,17β-dihydroxyestra-1,4-dien-3-one (DHED), a novel brain-targeting bioprecursor prodrug of the main human estrogen, 17β-estradiol, alleviates hot flushes in rat models of thermoregulatory dysfunction of the brain. Oral administration of DHED elicits a significant reduction of tail skin temperature (TST) rise representing hot flushes in the morphine-dependent ovariectomized rat model and results in the restoration of estrogen deprivation-induced loss of diurnal rhythm in TST. These beneficial effects occur without detrimental peripheral hormonal exposure; thus, the treatment avoids potentially harmful stimulation of estrogen-sensitive peripheral organs, including the uterus and the anterior pituitary, or the proliferation of MCF-7a breast cancer cell xenografts. Our promising preclinical assessments warrant further considerations of DHED for the development of a brain-selective 17β-estradiol therapy to relieve hot flushes without undesirable peripheral side-effects.

Olopatadine hydrochloride suppresses hot flashes induced by topical treatment with tacrolimus ointment in rats

Tacrolimus ointment is prescribed for patients with atopic dermatitis, although it is known to cause transient burning sensations and hot flashes in the applied skin. The aim of this study was to evaluate the effects of olopatadine hydrochloride (olopatadine), an antiallergic agent with a histamine H1 receptor (H1R) antagonistic activity, on the incidence of hot flashes induced by topical treatment with tacrolimus ointment in rats. Consequently, the skin temperature was increased by the topical application of tacrolimus ointment in rats, and the rise in skin temperature was inhibited by pretreatment with olopatadine in a dose-dependent manner. Inhibitory effect of olopatadine on tacrolimus-induced skin temperature elevation was significantly more potent than that of cetirizine hydrochloride, other antiallergic agent with H1R antagonistic activity, at doses in which both agents exhibit comparable H1R antagonistic activity in rats. These results suggest that H1R antagonistic activity-independent mechanism contribute to the inhibitory effect of olopatadine on tacrolimus-induced skin temperature elevation. Olopatadine also significantly inhibited increases in vascular permeability and nerve growth factor production in the skin induced by topical tacrolimus treatment. Thus, the onset of hot flashes in rats is quantitatively determined by measuring the skin temperature and olopatadine attenuates hot flashes induced by topical tacrolimus ointment in rats, suggesting that the combination application with olopatadine and tacrolimus ointment is useful for improving medication adherence with tacrolimus ointment treatment in patients with atopic dermatitis.

Infrared thermography based studies on mobile phone induced heating

Here, we report the skin temperature rise due to the absorption of radio frequency (RF) energy from three handheld mobile phones using infrared thermography technique. Experiments are performed under two different conditions, viz. when the mobile phones are placed in soft touch with the skin surface and away from the skin surface. Additionally, the temperature rise of mobile phones during charging, operation and simultaneous charging and talking are monitored under different exposure conditions. It is observed that the temperature of the cheek and ear regions monotonically increased with time during the usage of mobile phones and the magnitude of the temperature rise is higher for the mobile phone with higher specific absorption rate. The increase in skin temperature is higher when the mobile phones are in contact with the skin surface due to the combined effect of absorption of RF electromagnetic power and conductive heat transfer. The increase in the skin temperature in non-contact mode is found to be within the safety limit of 1°C. The measured temperature rise is in good agreement with theoretical predictions. The empirical equation obtained from the temperature rise on the cheek region of the subjects correlates well with the specific absorption rate of the mobile phones. Our study suggests that the use of mobile phones in non-contact mode can significantly lower the skin temperature rise during its use and hence, is safer compared to the contact mode.

Reply to letter: Acetaminophen and sport performance: doping or what?

effect of acetaminophen, although the subsequent results have shown that it does improve performance. Conse-quently, we would like to re-emphasise that we do not con-done the use of acetaminophen in sport as a performance aid, on both safety and ethical grounds.Although we have demonstrated that acetaminophen is capable of moderating the rise in core and skin temperature during exercise in the heat (which improved time to exhaus-tion) (Mauger and hopker 2014) and that it improves cor-ticospinal excitability in resting conditions (Mauger and hopker 2013), we believe that its primary mechanism of action is through analgesia. If this is the case, then any intervention (drug, dietary or otherwise) which can reduce the sensation of pain during moderate-long, dynamic rhyth-mical exercise has the potential to improve performance. Acetaminophen is globally available, has a very high inci-dence of use and is generally considered safe at therapeu-tic doses. Conversely, other analgesics such as tramadol, diclofenac, codeine and hydrocodone are not widely avail-able (but anecdotally are widely used by amateur athletes) and pose greater threats to health and/or are highly addic-tive. therefore, we suggest that there are other analgesics, which are currently being used to improve sporting perfor-mance, which should be addressed as a priority.Professors Lippi and Sanchis-Gom highlight the defini-tion of doping, according to the International Federation of Sports Medicine, as the deliberate or inadvertent use of sub-stances or methods to produce an unfair athletic advantage. Based on this (and the research evidence we present), they suggest that acetaminophen is included in the WADA list of banned substances (subject to therapeutic Use Exception). While we do not disagree that acetaminophen is likely a performance aid, the same definition would have to apply to wide variety of substances, which are routinely used in sport to aid performance yet not currently controlled

Heel Response to External Pressure

The purpose of the study was to determine whether the interface pressure created when the heel is in contact with the bed surface reduced healthy adults' heel oxygen delivery (transcutaneous oxygen [TcO2]) and raised heel skin temperature. We also determined whether there was a hyperemic response to pressure relief on 3 consecutive days, and compared data from healthy adults to that from hip surgery patients. A 1-group, prospective, repeated-measures design guided data collection and analysis. Eighteen subjects were age (±5 years) and gender-matched with a previous study on hip surgery patients. The mean age of study participants was 57.3 ± 15.75 (mean ± SD) years and half were men (n = 9). Oxygen and temperature sensors were placed on the plantar surface of each foot, close to the heels. Measures were taken when the heels were (1) suspended above the bed surface (preload), (2) on the bed surface for 15 minutes (loading), and (3) again suspended above the bed surface for 15 minutes (unloading).Repeated measures analysis of variance was used to analyze the data. When compared with preload, both loading and unloading on all 3 days resulted in a statistically significant bilateral reduction in heel TcO2 (P < .001) and a bilateral increase in heel skin temperature (P = .001). There was a significant bilateral heel hyperemic response (during the first 3 minutes of immediate heel unloading) on all 3 days. There were significant changes in heel TcO2 (P = .008) and heel skin temperature (P < .001) in both legs when pressure was relieved. The hyperemic response was not apparent in the operative leg in our prior hip surgery group. When comparing one of the legs of the healthy adults with the operative leg of the prior hip surgery patients, heel TcO2 in both groups decreased (P < .001) while heel skin temperature increased during both loading and unloading in all 3 days (P < .001). Heel TcO2 fell while heel skin temperature increased with both the application and removal of external pressure in healthy adults. The fall in TcO2 and the rise in heel skin temperature were also apparent in the operative leg of the hip surgery group. The brief period of hyperemia, measured by abrupt changes in heel TcO2 and heel skin temperature, was present only in healthy subjects. This raises the question of whether heel pressure ulcer development is related to a blunted hyperemic response in subjects with hip surgery. Further studies are needed that explore the effects of varying the duration of pressure on the hyperemic response as a strategy to understand heel pressure ulcer prevention. Since heel TcO2 fell in both groups after a brief pressure application of 15 minutes, nurses should keep heels off-load at all times to ensure adequate heel skin oxygenation.

Effect of lower body compression garments on hemodynamics in response to running session.

Purpose. Compression garments are often worn during exercise and allegedly have ergogenic and/or physiological effects. In this study, we compared hemodynamics and running performance while wearing compression and loose-fit breeches. We hypothesized that in neutral-warm environment compression breeches impair performance by diminishing body cooling via evaporative sweat loss and redistributing blood from active musculature to skin leading to a larger rise in body temperature and prolonging recovery of hemodynamics after exercise. Methods. Changes in hemodynamics (leg blood flow, heart rate, and blood pressure during orthoclinostatic test), calf muscle tissue oxygenation, and skin and core temperatures were measured in response to 30 min running (simulation of aerobic training session) followed by maximal 400 m sprint (evaluation of running performance) in recreationally active females (25.1 ± 4.2 yrs; 63.0 ± 8.6 kg) wearing compression or loose-fit breeches in randomized fashion. Results. Wearing compression breeches resulted in larger skin temperature rise under the garment during exercise and recovery (by about 1°C, P < 0.05; statistical power > 85%), while core temperature dynamics and other measured parameters including circulation, running performance, and sensations were similar compared to wearing loose-fit breeches (P > 0.05). Conclusion. Compared with loose-fit breeches, compression breeches have neither positive nor negative physiological and performance effects for females running in thermoneutral environment.

What is the inter and intra rater reliability among physiotherapists, sports medics and military nurses conducting functional assessments of injury risk?

of times is sudden from the second set appears. In succession to the decline, it was significantly skin temperature raise up when in 80 pitches to 100 on all veins (p<0.05). The skin temperature rise changed with all veins before approximately 120 pitches (rise) which was shown in prevention guidelines. Conclusions: With a non-contact type infrared rays thermometer, there were able to measure a change of the skin surface temperature with the pitching motion. Using this method, expects to prevent a pitching elbow.

Voluntary muscle and motor cortical activation during progressive exercise and passively induced hyperthermia

This study examined whether central fatigue was exacerbated by an increase in muscle contractile speed caused by passive hyperthermia (PaH) and whether exercise-induced hyperthermia (ExH) combined with related peripheral fatigue influenced this response. The ExH was induced by cycling at 60% of maximal oxygen uptake in 38°C conditions and the PaH by sitting in a 48°C climate chamber. Ten men performed brief (≈ 5 s) and sustained (30 s) maximal voluntary isometric contractions (MVCs) of the knee extensors at baseline (CON, ∼37.1°C) and during moderate (MOD, ≈ 38.5°C) and severe (SEV, ∼39.5°C) hyperthermia. Motor nerve and transcranial magnetic stimulation were used to assess voluntary muscle and cortical activation level, along with contractile properties. Brief MVC force decreased to a similar extent during SEV-ExH (-8%) and SEV-PaH (-6%; P < 0.05 versus CON). Sustained MVC force also decreased during MOD-ExH (-10%), SEV-ExH (-13%) and SEV-PaH (-7%; P < 0.01 versus CON). Motor nerve and cortical activation were reduced on reaching MOD (≈ 3%) and SEV (≈ 5%) ExH and PaH during the brief and sustained MVCs (P < 0.01 versus CON). Peak twitch force decreased on reaching SEV-ExH and SEV-PaH (P < 0.05 versus CON). Following transcranial magnetic stimulation, during the brief and sustained MVCs the peak muscle relaxation rate increased in ExH and PaH (P < 0.01 versus CON). The increase was greatest during the sustained contraction in SEV-PaH (P < 0.01), but this did not exacerbate central fatigue relative to ExH. These results indicate that during fatiguing cycling exercise in the heat, quadriceps peak relaxation rate increases. However, the centrally mediated rate of activation appears sufficient to overcome even the largest increase in muscle relaxation rate, seen during SEV-PaH.

Thermal Imaging of Exercise-Associated Skin Temperature Changes in Trained and Untrained Female Subjects

Heat dissipation during sport exercise is an important physiological mechanism that may influence athletic performance. Our aim was to test the hypothesis that differences exist in the dynamics of exercise-associated skin temperature changes between trained and untrained subjects. We investigated thermoregulation of a local muscle area (muscle-tendon unit) involved in a localized steady-load exercise (standing heels raise) using infrared thermography. Seven trained female subjects and seven untrained female controls were studied. Each subject performed standing heels raise exercise for 2 min. Thermal images were recorded prior to exercise (1 min), during exercise (2 min), and after exercise (7 min). The analysis of thermal images provided the skin temperature time course, which was characterized by a set of descriptive parameters. Two-way ANOVA for repeated measures detected a significant interaction (p = 0.03) between group and time, thus indicating that athletic subjects increased their skin temperature differently with respect to untrained subjects. This was confirmed by comparing the parameters describing the speed of rise of skin temperature. It was found that trained subjects responded to exercise more quickly than untrained controls (p < 0.05). In conclusion, physical training improves the ability to rapidly elevate skin temperature in response to a localized exercise in female subjects.