Lower Skin Temperature Research Articles

Human Responses to 5 Heated Hypothermia Wrap Systems in a Cold Environment

We compared the effectiveness of 5 heated hypothermia wrap systems. Physiologic and subjective responses were determined in 5 normothermic subjects (1 female) for 5 heated hypothermia wraps (with vapor barrier and chemical heat sources) during 60 min of exposure to a temperature of -22°C. The 5 systems were 1) user-assembled; 2) Doctor Down Rescue Wrap; 3) hypothermia prevention and management kit (HPMK); 4) MARSARS Hypothermia Stabilizer Bag; and 5) Wiggy's Victims Casualty Hypothermia Bag. Core and skin temperature, metabolic heat production, skin heat loss, and body net heat gain were determined. Subjective responses were also evaluated for whole body cold discomfort, overall shivering rating, overall temperature rating, and preferential ranking. The Doctor Down and user-assembled systems were generally more effective, with higher skin temperatures and lower metabolic heat production; they allowed less heat loss, resulting in higher net heat gain (P<0.05). HPMK had the lowest skin temperature and highest shivering heat production and scored worse than the other 4 systems for the "whole body cold discomfort" and "overall temperature" ratings (P<0.05). The user-assembled and Doctor Down systems were most effective, and subjects were coldest with the HPMK system. However, it is likely that any of the tested systems would be viable options for wilderness responders, and the choice would depend on considerations of cost; volume, as it relates to available space; and weight, as it relates to ability to carry or transport the system to the patient.

Exploring dynamic difficulty adjustment mechanism for rehabilitation tasks using physiological measures and subjective ratings

Task engagement is a key factor in sustaining patients’ participation in rehabilitation. Adaptive task difficulty level adjustment techniques are designed to determine the appropriate exercise difficulty level in where subjects are appropriately challenged and engaged without causing any distress. Such adaptive difficulty adjustment within rehabilitation tasks has the potential to individualise training. In this study, the authors have compared two dynamic difficulty level adjustment algorithms, partially ordered set master (POSM) and increment/decrement one level (IDOL), those change the difficulty levels for each individual adaptively based on his/her performance. These two algorithms are integrated into the robot-assisted rehabilitation system, RehabRoby, and their functionality is explored via a small user study with 20 healthy subjects. The subjects were asked to perform a computer-based fruit picker game using RehabRoby under these two algorithms. The impacts of the adaptation algorithms are evaluated in terms of engagement of the subjects by looking at their physiological signals, performance (score), and survey results. Experiments show that although POSM on the average suggests easier difficulty levels to the subjects than IDOL, the subjects experience a wider range of difficulty levels in POSM that may help them to become more engaged in the game, which can also be observed by lower skin temperatures of the subjects.

An Evaluation of Personal Cooling Systems for Reducing Thermal Strain Whilst Working in Chemical/Biological Protective Clothing.

ObjectiveThe use of personal cooling systems to mitigate heat strain on first-responders achieves two potential performance benefits relative to the absence of such cooling: (1) the completion of a workload with less effort; and/or (2) the completion of a greater workload for the same effort. Currently, claims made by manufacturers regarding the capability of their products for use in conjunction with chemical/biological protective clothing remain largely unsubstantiated. The purpose of this investigation was to evaluate the means by which heat strain can be alleviated during uncompensable heat stress in chemical/biological clothing, using the ASTM F2300-10 methodology.MethodsEight healthy males completed five trials of continuous walking (4.5 km h−1; 35°C; 49% RH) for up to 120 min while wearing one of four cooling systems and/or a National Fire and Protection Association 1994 Class-3 chemical/biological ensemble. The four cooling methods (ice vest [IV], phase-change vest [PCM], water-perfused suit [WS], and combination ice slurry/ice vest [SLIV]) and no cooling (CON).ResultsWe observed significant improvements in trial times for IV (18 ± 10 min), PCM (20 ± 10 min) and SLIV (22 ± 10 min), but no differences for WS (4 ± 7 min). Heart rate, rectal, mean skin, and body temperatures were significantly lower in all cooling conditions relative to control at various matched time points in the first 60 min of exercise. Thermal sensation, comfort and perceived exertion all had significant main effects for condition, and time, there were no differences in their respective interactions.ConclusionThe IV, PCM, and SLIV produced lower heart rate, mean skin, rectal and mean body temperatures in addition to improved work times compared to control. The WS did not improve work times possibly as a result of the cooling capacity of the suit abating, and magnifying thermal insulation. Considering the added time and resources required to implement combination cooling in the form of ice slurry and ice vest (SLIV), there was no significant additive effect for perception, cardiovascular strain, rectal temperature and total trial time relative to the phase change vest or ice vest alone. This may be a product of a “ceiling” effect for work limit set to 120 min as part of ASTM F2300-10.

Validation of a Device for the Ambulatory Monitoring of Sleep Patterns: A Pilot Study on Parkinson's Disease

The development of wearable devices has increase interest in the use of ambulatory methods to detect sleep disorders more objectively than those permitted by subjective scales evaluating sleep quality, while subjects maintain their usual lifestyle. This study aims to validate an ambulatory circadian monitoring (ACM) device for the detection of sleep and wake states and apply it to the evaluation of sleep quality in patients with Parkinson disease (PD). A polysomnographic validation study was conducted on a group of patients with different sleep disorders in a preliminary phase, followed by a pilot study to apply this methodology to PD patients. The ACM device makes it possible to estimate the main sleep parameters very accurately, as demonstrated by: (a) the lack of significant differences between the mean values detected by PSG and ACM in time in bed (TIB), total sleep time (TST), sleep efficiency (SE), and time awake after sleep onset (WASO); (b) the slope of the correlation lines between the parameters estimated by the two procedures, very close to 1, which demonstrates the linearity of the predictions; (c) the low bias value in the estimates obtained through ACM. Sleep in PD is associated with lower distal skin temperature, efficiency and overall sleep time; greater WASO, activity during sleep and duration of naps and a worse circadian function index. In summary, the ACM device has proven to be clinically useful to evaluate sleep in an objective manner, thanks to the integrated management of different complementary variables, having advantages over conventional actigraphy.

Ski-Everest (8848 m) Expedition: Digit Skin Temperature Responses to Cold Immersion May Reflect Susceptibility to Cold Injury

We tested the hypothesis that individual susceptibility to freezing cold injury might be reflected in an attenuated cold-induced vasodilatation (CIVD) response by comparing the CIVD responses of an elite alpinist with a history of freezing cold injury in the feet (case alpinist) with those of an age- and ability- matched noninjured alpinists control group (controls). According to this hypothesis, the vasomotor responses to a CIVD test of the case alpinist would represent a pathophysiological response when compared with the normal physiological response of a noninjured cohort. The case alpinist and the controls in the cohort group conducted a cold water immersion test comprising sequential immersion of a hand and foot for 5 min in 35°C water, followed by a 30-min immersion in 8°C water and a 10-min recovery period in room air. During this test we monitored the finger and toe skin temperatures. The case alpinist had a significantly attenuated CIVD response and a lower skin temperature in all injured and noninjured digits during immersion (∼2°C lower than in the control group) and an attenuated recovery of finger skin temperatures (∼6°C lower than in the control group). The attenuated CIVD response of the case alpinist may reflect a previously unrecognized enhanced susceptibility to frostbite. In addition to the poor vasomotor response observed in the injured toes, he also exhibited a poor vasomotor response in his noninjured fingers. The results of the present study indicate that a test of vasomotor activity during thermal stress may identify individuals predisposed to cold injury.

Local cryostimulation acutely preserves maximum isometric handgrip strength following fatigue in young women

Several types of cryostimulation have been recently proposed to rapidly lower skin temperature therefore gaining a possible neuro/muscular recovery after strenuous exercise or, more generally, in sports. Local cryostimulation may be a viable and relatively portable tool to obtain physiological benefits in previously-efforted muscular districts. However, cohesive and standardized cryo-exposure protocols are lacking as well as the righteous procedure to efficaciously combine duration, treatments and temperature in relation to desirable effects on muscular strength. In this randomized-controlled study, fifty young women were tested for maximum isometric handgrip strength, before and after exhausting contractions.Following the fatiguing protocol, the intervention group (cryo, n = 25, 24.7 ± 2.5 years, BMI 21.7 ± 1.8 kg/m2) underwent a 6-min local cryostimulation (−160 °C) on the extensor-flexor muscles of the dominant arm, while control-matched peers sat rested in a thermo-neutral room (22 ± 0.5 °C). Handgrip tests were repeated at baseline (T0), after cryostimulation (T1), and 15 min after T1 (T2). Throughout the protocol, the AUC of the strength performance was significantly higher in the cryo- compared to control group (P = 0.006). In particular, following fatigue and cryostimulation, the cryo group preserved higher strength at T1 with respect to controls (26.8 ± 2.8 vs 23.9 ± 2.8 kg, Bonferroni's post-hoc, P < 0.01). Likewise, ventral and dorsal temperature, recorded with a thermal camera, were lower in cryo- than control group (P < 0.0001).In conclusion, a brief session of local cryostimulation may acutely preserve maximal isometric force in young women following a fatiguing protocol. These findings may have implications in orchestrating strategies of district muscular recovery.

Internal precooling decreases forehead and core temperature but does not alter choice reaction time during steady state exercise in hot, humid conditions

This study aimed to determine if precooling via crushed ice ingestion reduces forehead skin temperature (Thead) and core temperature (Tcore) during exercise in the heat and whether it has an effect on choice reaction time (CRT). Ten males commenced a 30 min precooling period, ingesting either 7 g kg−1 of crushed ice (ICE) or room temperature water (CON) prior to cycling 60 min at 55% V̇O2peak in hot, humid conditions (35.0 ± 0.3 °C, 50.2 ± 2.1% Relative Humidity). The CRT task was completed upon arrival and after the precooling period in the lab, then at 15 min intervals during exercise in the heat. Precooling reduced Thead and Tcore to a greater degree in ICE (Thead: −0.8 ± 0.31 °C; Tcore: −0.9 ± 0.3 °C) compared with CON (Thead: −0.2 ± 0.3 °C; Tcore: −0.2 ± 0.2 °C) (p ≤ 0.001). Choice reaction time performance improved throughout the cycle for both conditions (p ≤ 0.05). Ice ingestion lowered thermal sensation (p = 0.003) and skin temperature (d = 0.88; Tskin), while heart rate, ratings of perceived exertion and thirst were similar between conditions (p > 0.05). Precooling effectively reduced Thead and Tcore but did not provide additional improvement in CRT during moderate exercise in the heat. Further investigation is required to determine whether the lower central and peripheral temperature after ice ingestion is beneficial for tasks of greater cognitive effort.

Thermal comfort under radiant asymmetries of floor cooling system in 2 h and 8 h exposure durations

Radiant heating and cooling systems inherently exhibit radiant asymmetries. Although many researchers have investigated the thermal comfort effects of asymmetric radiant environments, the exposure duration has not been emphasized, especially under floor heating and cooling scenarios. In this study, we conducted a series of tests in a climate chamber with floor cooling radiant asymmetries with human participants to investigate their thermal comfort effects from short-term (2 h) and long-term (8 h) exposure perspectives. The 2 h exposure test indicates that the floor cooling systems cause discomfort complaints more easily than other radiant systems such as ceiling heating/cooling because of its stronger cooling effects on the lower body parts. The cold floor resulted in significantly colder local thermal sensations and lower local skin temperatures in the foot, calf, and thigh areas. The comparison between the 2 h and 8 h exposures suggests that exposure duration affects both the subjective and physiological thermal comfort responses significantly. 2.5∼4 h are required for the foot and calf temperatures to stabilize in radiant floor cooling asymmetry cases. In accordance with these laboratory tests, we proposed two radiant asymmetry-satisfaction curves and equations for the floor cooling system with consideration of exposure duration. The calculated temperature limits for typical floor cooling room are >18.5 °C at a 2 h exposure and >20.5 °C at an 8 h exposure. These curves and temperature limits can serve as a reference for future guidelines for floor cooling system design and operation.

Impairment of Cycling Capacity in the Heat in Well-Trained Endurance Athletes After High-Intensity Short-Term Heat Acclimation.

To investigate the effects of short-term, high-intensity interval-training (HIIT) heat acclimation (HA). Male cyclists/triathletes were assigned into either an HA (n = 13) or a comparison (COMP, n = 10) group. HA completed 3 cycling heat stress tests (HSTs) to exhaustion (60% Wmax; HST1, pre-HA; HST2, post-HA; HST3, 7 d post-HA). HA consisted of 30-min bouts of HIIT cycling (6min at 50% Wmax, then 12 × 1-min 100%-Wmax bouts with 1-min rests between bouts) on 5 consecutive days. COMP completed HST1 and HST2 only. HST and HA trials were conducted in 35°C/50% relative humidity. Cycling capacity and physiological and perceptual data were recorded. Cycling capacity was impaired after HIIT HA (77.2 [34.2]min vs 56.2 [24.4]min, P = .03) and did not return to baseline after 7 d of no HA (59.2 [37.4]min). Capacity in HST1 and HST2 was similar in COMP (43.5 [8.3] min vs 46.8 [15.7]min, P = .54). HIIT HA lowered resting rectal (37.0°C [0.3°C] vs 36.8°C [0.2°C], P = .05) and body temperature (36.0°C [0.3°C] vs 35.8°C [0.3°C], P = .03) in HST2 compared with HST1 and lowered mean skin temperature (35.4°C [0.5°C] vs 35.1°C [0.3°C], P = .02) and perceived strain on day 5 compared with day 1 of HA. All other data were unaffected. Cycling capacity was impaired in the heat after 5 d of consecutive HIIT HA despite some heat adaptation. Based on data, this approach is not recommended for athletes preparing to compete in the heat; however, it is possible that it may be beneficial if a state of overreaching is avoided.

Ojayeonjonghwan, an oriental medicine composed of five seeds, protects against vasomotor and neurological disorders in estrogen-deficient rats.

Menopausal symptoms impair the quality of life of many women, and although conventional treatments are often effective, their use is limited by adverse effects. Ojayeonjonghwan, OJa, is a traditional Oriental medicine that is used for both male and female reproductive health and has a long history of safe use. We evaluated the effectiveness of two variations of OJa (OJa1 and OJa2) for treating menopausal symptoms in ovariectomized (OVX) rats. Both OJa preparations were effective for relieving indicators of hot flashes and depression, and for preventing loss of bone mineral density and lean body mass. Only OJa 2 prevented memory dysfunction. These results show that the traditional Oriental medicine, Ojayeonjonghwan, has the potential to relieve menopausal symptoms in women and should be further evaluated in human clinical trials as an alternative to convention therapies in women for whom conventional therapies are not indicated or found to be ineffective.

Distal skin vasodilation in sleep preparedness, and its impact on thermal status in preterm neonates

ObjectivePrior to sleep onset in human adults, distal body temperatures change progressively from wakefulness levels (low skin temperatures and a high core temperature) to sleep levels (high skin temperatures and a low core temperature) due to distal skin vasodilation and greater body cooling. It is not known whether this sleep preparedness exists in preterm neonates, even though sleep has a key role in neonatal health and neurodevelopment. The present study's objectives were to determine whether sleep preparedness (as observed in adults) can be evidenced in preterm neonates, and to assess repercussions on thermal stress. MethodsDuring a 12-h night-time polysomnography session, skin temperatures (recorded with an infrared camera), sleep, and wakefulness episodes were measured in 18 nine-day-old preterm neonates. ResultsFifteen wakefulness episodes were considered. Our results highlighted significant pre-sleep distal skin vasodilation (mainly at the foot: an increase of 0.38 °C in the 20 min preceding sleep onset) for the first time in preterm neonates. This vasodilation occurred even though (1) most factors known to influence pre-sleep vasodilation in adults were not present in these neonates, and (2) the neonates were nursed in a nearly constant thermal environment. The vasodilatation-related increase in body heat loss corresponded to a 0.15°C/h fall in mean body temperature (calculated using partitional calorimetry). ConclusionCompensation for this body heat loss and the maintenance of body homeothermia would require a 4% increase in metabolic heat production. In neonates, this type of energy expenditure cannot be maintained for a long period of time.

Evaluating physiological signal salience for estimating metabolic energy cost from wearable sensors.

Body-in-the-loop optimization algorithms have the capability to automatically tune the parameters of robotic prostheses and exoskeletons to minimize the metabolic energy expenditure of the user. However, current body-in-the-loop algorithms rely on indirect calorimetry to obtain measurements of energy cost, which are noisy, sparsely sampled, time-delayed, and require wearing a respiratory mask. To improve these algorithms, the goal of this work is to predict a user's steady-state energy cost quickly and accurately using physiological signals obtained from portable, wearable sensors. In this paper, we quantified physiological signal salience to discover which signals, or groups of signals, have the best predictive capability when estimating metabolic energy cost. We collected data from 10 healthy individuals performing 6 activities (walking, incline walking, backward walking, running, cycling, and stair climbing) at various speeds or intensities. Subjects wore a suite of physiological sensors that measured breath frequency and volume, limb accelerations, lower limb EMG, heart rate, electrodermal activity, skin temperature, and oxygen saturation; indirect calorimetry was used to establish the 'ground truth' energy cost for each activity. Evaluating Pearson's correlation coefficients and single and multiple linear regression models with cross validation (leave-one- subject-out and leave-one- task-out), we found that 1) filtering the accelerations and EMG signals improved their predictive power, 2) global signals (e.g., heart rate, electrodermal activity) were more sensitive to unknown subjects than tasks, while local signals (e.g., accelerations) were more sensitive to unknown tasks than subjects, and 3) good predictive performance was obtained combining a small number of signals (4-5) from multiple sensor modalities. NEW & NOTEWORTHY In this paper, we systematically compare a large set of physiological signals collected from portable sensors and determine which sensor signals contain the most salient information for predicting steady-state metabolic energy cost, robust to unknown subjects or tasks. This information, together with the comprehensive data set that is published in conjunction with this paper, will enable researchers and clinicians across many fields to develop novel algorithms to predict energy cost from wearable sensors.

Brown adipose tissue thermogenesis in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is associated with increased obesity with a greater propensity to weight gain and a lack of sustainable lifestyle interventions. Altered brown adipose tissue (BAT) thermogenesis is a potential contributor to obesity in PCOS. BAT activity and modulation have not been studied in PCOS. This observational study explored BAT thermogenesis and its associations in women with and without PCOS. Cutaneous temperature was recorded from supraclavicular (indicator of BAT activity) and upper arm regions using dataloggers (SubCue, Calgary, Canada) in a cross-sectional substudy, nested within a randomized control trial, of community-recruited premenopausal women with (n=47, Rotterdam diagnostic criteria) and without (n=11) PCOS. Complete temperature data were available in 44 PCOS (mean age: 30.0±6.2, mean BMI: 29.3±5.5) and 11 non-PCOS (mean age: 33.0±7.0, mean BMI: 25±3) women. Women with PCOS had lower supraclavicular skin temperature compared to controls overall (33.9±0.7 vs 34.5±1, P<0.05) and during sleep (34.5±0.6 vs 35.2±0.9, P<0.001). In the PCOS group, supraclavicular skin temperature overall and over sleep and waking hours correlated inversely with testosterone (r=-0.41 P<0.05, r=-0.485 P<0.01 and r=-0.450 P<0.01 respectively). Testosterone levels explained approximately 15%, 30% and 20% of the variability in supraclavicular skin temperature overall and over sleep and waking hours in women with PCOS, respectively. Women with PCOS have lower BAT activity compared to controls. BAT thermogenesis is negatively associated with androgen levels in PCOS.

Occupant behaviour and thermal comfort in buildings: Monitoring the end user

Studies indicate that the energy performance gap between real and calculated energy use can be explained for 80% by occupant behaviour. This human factor may be composed of routine and thermoregulatory behaviour. When occupants do not feel comfortable due to high or low operative temperatures and resulting high or low skin temperatures, they are likely to exhibit thermoregulatory behaviour. The aim of this study is to monitor and understand this thermoregulatory behaviour of the occupant. This is a detailed study of two females living in a rowhouse in the city of Heerlen (Netherlands). During a monitoring period of three weeks over a time span of three months the following parameters were monitored: activity level, clothing, micro climate, skin temperatures and thermal comfort and sensation. Their micro climate was measured at five positions on the body to assess exposed near body conditions and skin temperature. Every two hours they filled in a questionnaire regarding their thermal comfort and sensation level (7-point scale), clothing, activities and thermoregulatory behaviour. The most comfortable (optimal) temperature was calculated for each person by adopting a biophysical model, a thermoneutral zone model. This study shows unique indivual comfort patterns in relation to ambient conditions. An example is given how this information can be used to calculate the buildings energy comsumption.

Body Temperature Responses and Hair Cortisol Levels in Dairy Holstein Cows Fed High- and Low-Forage Diet and Under Water Deprivation During Thermal-Humidity Exposure

Abstract Body temperature responses and hair cortisol levels in dairy Holstein cows fed high- and low-forage diet and under water deprivation during thermal-humidity exposure (THE) were evaluated. Two experiments (Exps.) were conducted between July and September 2012 and 2013 for 64 d and 74 d, respectively. First, twenty dairy Holstein cows (90±30 DIM; 37.2±1.7 l milk/d, 620±75 kg BW) were used. The practical forage:concentrate (F:C) ratios in the low forage (LF) and high forage (HF) group were 44:56 and 56:44, respectively, while they were designed to be 40:60 and 60:40. Second, thirty dairy cows (53.5±30.4 DIM; 41.7±1.5 l milk/d,650±53 kg BW) were allotted into two groups of free access to water (FAW) and 2 h water deprivation (2hWD) following feeding. The animals were subjected to having the hair cut (1 to 2 g) from their foreheads at the same time (12:00 h) twice at the beginning (prior to the beginning of heat stress) and the end of the experiment when the cows were under THE. Hair cortisol levels (initial hair cut as the baseline and re-grown hair) were measured using ELISA method. Body temperature (BT) was measured twice daily at 7 body points of cows including rectum, vagina, hip, udder, rumen-side (flank), ear, and forehead using non-contact forehead infrared thermometer (infrared gun having two modes: inner and skin) on the 7 d of the beginning and the last 7 d of the experiment at 1000 and 1400 h. Statistical analyses were carried out using the MIXED model of SAS as repeated measurements. The intra-assay and inter-assay coefficients of variations for hair cortisol measurements were 3.15 and 10.05, respectively. Hair cortisol (HC) levels were not different within the two groups in both Exps. (P&gt;0.05); however, HC level was lower (P&lt;0.0001) prior to temperature-humidity exposure (THE). Results of Exp. 1 showed that vagina inner temperature was higher (P=0.041) and rectal temperature tended to be higher (P=0.083) in the HF compared to the LF group. The inner ear temperature was lower and ear skin temperature was higher (P=0.032) in the HF compared to the LF group. Forehead inner temperature was higher (P=0.048) in the LF group than in the HF group while forehead skin temperature was lower in the HF group (P=0.041). No differences were observed in the hip, udder and rumen-side (flank) temperature (both in body and skin) between the HF and LF group (P=0.012). In Exp. 2, no temperature differences were observed at all of the body points, inner and skin, between the two groups (P&gt;0.05). However, the skin temperature in the 2hWD groups tended to be higher than in the FAW group (P=0.093). Conclusions drawn indicate the beneficial use of measuring BT at different body points of the cow in addition to RT under THE.

Effect of Forearm Warming Compared to Hand Warming for Cold Intolerance Following Upper Extremity Trauma

This study evaluated the effect of forearm or hand warming versus bare hand conditions to improve cold-induced symptoms and skin temperatures in hand trauma patients. Adults with symptoms of cold intolerance at least 3 months following hand trauma and age-/sex-matched controls were included. Testing sessions (bare hand, hand warming, forearm warming) were completed in a climate laboratory with continuous temperature monitoring. Outcomes included physical findings (skin temperature) and self-report symptoms (thermal comfort, pain). Eighteen participants (9 hand trauma patients, 9 control subjects) underwent testing. More severe cold intolerance was associated with higher Disabilities of the Arm, Shoulder, and Hand scores. With bare hands, skin temperatures changed significantly from baseline to cold exposure and to rewarming. Hand trauma patients had the lowest skin temperatures with cold exposure in the injured digits (14.3°C ± 3.5°C) compared with the contralateral uninjured (16.9°C ± 4.1°C) digits. Compared with bare hands, wearing gloves significantly increased the minimum temperature during cold exposure and the maximum temperature after rewarming. Patients reported higher pain with cold exposure. All participants reported significantly more comfort with less coldness with forearm and hand warming. There was cold response variability in hand trauma patients and control subjects. Hand trauma patients had greater changes in skin temperature during cold exposure that improved with glove warming. Continuous temperature monitoring identified subtle physiological changes associated with cold-induced pain and with warming interventions. Therapeutic III.

Muscle skin temperature responses for hamstring and quadriceps to aerobic and anaerobic test conditions in Turkish Olympic Sailing Athletes

Olympic class sailing is a competitive sport and requires several abilities. An understanding of the responses to aerobic and anaerobic loading will be useful for assessing the training programs, protective strategies and possibility of injuries. Therefore, the aim of this study is to determine lower extremity main muscles skin temperature responses to aerobic and anaerobic test conditions in Turkish Olympic Sailing Athletes. Eighteen sailing athletes were assessed during preseasonal assessment period. Temperatures of quadriceps and hamstring muscle groups were evaluated bilaterally during rest and after Wingate Treadmill tests. Wingate test was accepted as an indicator of anaerobic performance and Treadmill test as an aerobic performance. Infrared thermography was performed to assess the skin temperature at anterior and posterior parts of thigh for both legs. In the triplicate comparison, the temperature changes between the rest, aerobic test and anaerobic test conditions were significant (p < 0.05). In the analysis to determine the difference between the compared groups; for both muscle groups, temperature change after anaerobic performance was not significant; in contrast to this result the change in muscle temperature after aerobic performance was significant (p < 0.05). Energetic—metabolic activity of major muscle groups of lower extremities during aerobic and anaerobic performance are important for injury prevention, treatment, rehabilitation and return to play. Present study shows that aerobic performance or activities requires higher energetic-metabolic activity.

The effects of walking posture on affective and physiological states during stress

Background and objectivesEmbodiment theory proposes that motor processes are associated with emotions and cognitions. Previous research has shown that walking posture can influence affective memory bias. This study further investigated this theory by looking at the effects of an upright versus slumped walking posture on psychological and physiological states when faced with a psychological stressor. MethodsSeventy-three healthy adults completed baseline self-report measures of affect, power, and sleepiness, and physiological measures of blood pressure, galvanic skin response, and skin temperature. After walking in their usual posture, the same self-report and physiological measures were obtained. Participants were then randomly allocated into one of two groups where they were asked to walk in either an upright posture or a slumped posture. While walking, participants underwent a psychological stressor. After experimental walking, the same self-report and physiological measures were obtained. ResultsThe upright walking posture group showed significantly improved psychological states including less low arousal negative affect, less sleepiness, less pain and marginally greater feelings of power than the slumped walking posture group. Physiologically, the upright walking posture group showed significantly lower systolic blood pressure, galvanic skin response, and marginally lower skin temperature than the slumped walking posture group. LimitationsThis was a short-term laboratory-based experiment and results may not generalise to other situations. ConclusionsWalking posture can affect both psychological and physiological states. Applications of these findings may have implications for improving mental and physiological health.

On the use of a novel nanoporous polyethylene (nanoPE) passive cooling material for personal thermal comfort management under uniform indoor environments

Passive cooling materials such as specially designed nanoporous microfibers are nearly transparent to infrared thermal radiation emitted from the human body. Hence, such passive cooling materials have the potential to help indoor occupants attain thermal comfort through regulating the radiative body heat in indoor conditions. In this work, a regular fit women's business shirt made of the nanoporous polyethylene (nanoPE) material was designed and its cooling performance under four uniform indoor conditions was examined. A cotton shirt (CO) with the same size and pattern as the nanoPE shirt was designed and selected as the control. Eighteen female participants underwent eight 80-min trials at four indoor temperatures: 23, 25, 27 and 29 °C. Trials were performed in simulated indoor environments where RH = 60% and the air velocity was kept below 0.10 m/s. Results have demonstrated that participants had significantly lower mean skin temperatures, mean upper torso temperatures and forearm temperatures in nanoPE as compared to CO at 23, 25 and 27 °C. Participants showed the maximum satisfaction with the thermal environment while wearing the CO clothing at 25 °C, whereas they were mostly satisfied with the thermal environment while wearing the nanoPE clothing at 27 °C. Thus, the acceptable air conditioning setpoint temperature could be extended by 1.5 °C from 25.5 to 27 °C while using the nanoPE clothing and thereby, this saves about 9–15% cooling energy. Finally, it was concluded that the nanoPE passive cooling clothing contributes to enhancing indoor thermal comfort under uniform environments and saving significant cooling energy.

Limb Skin Temperature as a Tool to Predict Orthostatic Instability.

Orthostatic instability is one of the main consequences of weightlessness or gravity challenge and plays as well a crucial role in public health, being one of the most frequent disease of aging. Therefore, the assessment of effective countermeasures, or even the possibility to predict, and thus prevent orthostatic instability is of great importance. Heat stress affects orthostatic stability and may lead to impaired consciousness and decrease in cerebral perfusion, specifically during the exposure to G-forces. Conversely, peripheral cooling can prevent orthostatic intolerance – even in normothermic healthy subjects. Indicators of peripheral vasodilation, as elevated skin surface temperatures, may mirror blood decentralization and an increased risk of orthostatic instability. Therefore, the aim of this study was to quantify orthostatic instability risk, by assessing in 20 fighter jet pilot candidates’ cutaneous limb temperatures, with respect to the occurrence of G-force-induced almost loss of consciousness (ALOC), before and during exposure to a push-pull maneuver, i.e., head-down tilt, combined with lower body negative pressure. Peripheral skin temperatures from the upper and lower (both proximal and distal) extremities and core body temperature via heat-flux approach (i.e., the Double Sensor), were continuously measured before and during the maneuver. The 55% of subjects that suffered an ALOC during the procedure had higher upper arm and thigh temperatures at baseline compared to the 45% that remained stable. No difference in baseline core body temperature and distal limbs (both upper and lower) skin temperatures were found between the two groups. Therefore, peripheral skin temperature data could be considered a predicting factor for ALOC, prior to rapid onset acceleration. Moreover, these findings could also find applications in patient care settings such as in intensive care units.