Finger Skin Temperature Research Articles

Investigation of Gender Differences in Sleeping Comfort at Different Environmental Temperatures

The purpose of this investigation was to determine whether there is gender difference in sleep comfort of healthy individuals at various temperatures. During winter, sleep quality was examined under different indoor temperatures (17, 20 and 23°C) using questionnaires and electroencephalogram (EEG). To explore the mechanism responsible for gender differences in comfortable sleeping temperatures, mean skin temperature, finger temperature and finger blood flow were measured. The results showed that females would prefer a higher ambient temperature during sleep than the men. The mean skin temperature for females was higher than that of males, whereas finger skin temperature and finger blood flow were significantly lower in females than in males. Furthermore, skin temperature and finger blood flow were more sensitive to ambient temperature with females than in males. The gender differences in preferred sleeping temperature could therefore be related to these physiological characteristics. Both subjective evaluations and EEG found better sleep quality in males under the same temperatures compared to females. Skin temperature changes over the course of the night also demonstrated longer periods of deep sleep in males compared to females.

Trainability of cold induced vasodilatation in fingers and toes

Subjects that repeatedly have to expose the extremities to cold may benefit from a high peripheral temperature to maintain dexterity and tissue integrity. Therefore, we investigated if repeated immersions of a hand and a foot in cold water resulted in increased skin temperatures. Nine male and seven female subjects (mean 20.4; SD 2.2 years) immersed their right (trained) hand and foot simultaneously in 8°C water, 30 min daily for 15 days. During the pre and post-test (days 1 and 15, respectively) the left (untrained) hand and foot were immersed as well. Pain, tactile sensitivity and skin temperatures were measured every day. Mean (SD) toe temperature of the trained foot increased from 9.49°C (0.89) to 10.03°C (1.38) (p < 0.05). The trained hand, however, showed a drop in mean finger temperature from 9.28°C (0.54) to 8.91°C (0.44) (p < 0.001) and the number of cold induced vasodilation (CIVD) reactions decreased from 52% during the first test to 24% during the last test. No significant differences occurred in the untrained extremities. Pain diminished over time and tactile sensitivity decreased with skin temperature. The combination of less CIVD responses in the fingers after training, reduced finger skin temperatures in subjects that did show CIVD and the reduced pain and tactile sensitivity over time may lead to an increased risk for finger cold injuries. It is concluded that repeated cold exposure of the fingers does not lead to favorable adaptations, but may instead increase the injury risk.

Digital infrared thermographic imaging for remote assessment of traumatic injury

The purpose of this study was to test the hypotheses that digital infrared thermographic imaging (DITI) during simulated uncontrolled hemorrhage will reveal 1) respiratory rate and 2) changes of skin temperature that track reductions of stroke volume. In 45 healthy volunteers (25 men and 20 women), we recorded the ECG, finger photoplethysmographic arterial pressure, respiratory rate (pneumobelt and DITI of the nose), cardiac output (inert rebreathing), and skin temperature of the forehead during lower body negative pressure (LBNP) at three continuous decompression rates; slow (-3 mmHg/min), medium (-6 mmHg/min), and fast (-12 mmHg/min) to an ending pressure of -60 mmHg. Respiratory rates calculated from the pneumobelt (14.7 ± 0.9 breaths/min) and DITI (14.9 ± 1.2 breaths/min) were not different (P = 0.21). LBNP induced an average stroke volume reduction of 1.3 ml/mmHg regardless of decompression speed. Maximal reductions of stroke volume and forehead temperature were -100 ± 12 ml and -0.32 ± 0.12°C (slow), -86 ± 12 ml and -0.74 ± 0.27°C (medium), and -78 ± 5 ml and -0.17 ± 0.02°C (fast). Changes of forehead temperature as a function of changes of stroke volume were best described by a quadratic fit to the data (slow R(2) = 0.95; medium R(2) = 0.89; and fast R(2) = 0.99).Our results suggest that a thermographic camera may prove useful for the remote assessment of traumatically injured patients. Life sign detection may be determined by verifying respiratory rate. Determining the magnitude and rate of hemorrhage may also be possible based on future algorithms derived from associations between skin temperature and stroke volume.

Reductions in finger blood flow in men and women induced by 125-Hz vibration: association with vibration perception thresholds

Vibration of one hand reduces blood flow in the exposed hand and in the contralateral hand not exposed to vibration, but the mechanisms involved are not understood. This study investigated whether vibration-induced reductions in finger blood flow are associated with vibrotactile perception thresholds mediated by the Pacinian channel and considered sex differences in both vibration thresholds and vibration-induced changes in digital circulation. With force and vibration applied to the thenar eminence of the right hand, finger blood flow and finger skin temperature were measured in the middle fingers of both hands at 30-s intervals during seven successive 4-min periods: 1) pre-exposure with no force or vibration, 2) pre-exposure with force, 3) vibration 1, 4) rest with force, 5) vibration 2, 6) postexposure with force, and 7) recovery with no force or vibration. A 2-N force was applied during periods 2-6 and 125-Hz vibration at 0.5 and 1.5 ms(-2) root mean square (r.m.s.; unweighted) was applied during periods 3 and 5, respectively. Vibrotactile thresholds were measured at the thenar eminence of right hand using the same force, contact conditions, and vibration frequency. When the vibration magnitude was greater than individual vibration thresholds, changes in finger blood flow were correlated with thresholds (with both 0.5 and 1.5 ms(-2) r.m.s. vibration): subjects with lower thresholds showed greater reductions in finger blood flow. Women had lower vibrotactile thresholds and showed greater vibration-induced reductions in finger blood flow. It is concluded that mechanoreceptors responsible for mediating vibration perception are involved in the vascular response to vibration.

Physiological and psychological responses induced by expressing empathy with others

To assess the physical and mental burdens associated with expressing empathy with another person's stress. Nine female subjects listened to their partner's negative emotions aroused by a stress task (Stroop color-word test) under two conditions. In the first, the subject reacted empathetically to their partner ("with empathy"); in the second, the subject offered no response (control). Electroencephalograms and skin temperature of the second finger were recorded during the test. Subjective stress was estimated using a visual analog scale, whereas the level of cognition was expressed on a five-point ranking. Responses during and after expressions of empathy were examined by comparisons with control or by correlation. Sympathetic nerve tone increased under both conditions (i.e. the skin temperature of the second finger fell). Subjective stress was not recognized by the subject while listening "with empathy", although it did increase significantly after the subject has listened "with empathy". Subjective stress was not felt under the control conditions. Right temporal activity while listening showed a significantly positive correlation with the level of cognition of feeling the same emotion as the stressed partner, whereas bilateral frontal activity after listening was significantly negative correlated with the level of cognition of understanding the emotions of the stressed partner. Expressing empathy with another person's negative emotion led to increased physiological activity and subjective stress. Physiological responses to empathy depended on cognition of the different subjective factors. Cognition of sharing negative emotions activated the right temporal region of the brain, whereas cognition of understanding negative emotions inhibited bilateral frontal activities.

Diagnostic performance of cold provocation test with hands immersion in water at 10°C for 5 min evaluated in vibration-induced white finger patients and matched controls

This study aimed to explore the diagnostic ability of the cold provocation test with hands immersion in water at 10°C for 5min in diagnosing vibration-induced white finger (VWF). Finger skin temperature (FST) was measured in 20 VWF patients and 20 matched healthy controls, at palmar side of the distal phalanges of fingers from both hands before, during, and after hands immersion in water at 10°C (for 5min with waterproof coverings put on both hands). Data from 4 fingers (except thumb) were evaluated at five time points: just before immersion, last minute during immersion, and at 5th, 10th, and 15th min during the post-immersion or recovery period. A positive group difference between patients and controls was revealed during the recovery period. During recovery at 95 and 70% specificity, the sensitivity ranged from 20 to 30% and 50 to 70% for evaluation with average FST for 4 fingers and 15-35% and 60-65% for evaluation with minimum FST among 4 fingers, respectively. Overall, evaluation of absolute FST at 15th min of recovery offered better diagnostic ability. The cold provocation test with hands immersion in water at 10°C for 5min could discriminate VWF patients from healthy controls; however, this test has a limited diagnostic value in diagnosing patients with VWF.

Reproducibility of pulse contour analysis in children before and after maximal exercise stress test: The Physical Activity and Nutrition in Children (PANIC) Study

Arterial stiffness index (SI) and reflection index (RI) from digital pulse contour analysis have been shown to be good measures of arterial stiffness and may be useful in the evaluation of endothelial function. Finger skin temperature (FST) is also considered to reflect peripheral circulatory functions. We evaluated the reproducibility of SI, RI and FST before and after the exercise stress test. The subjects were 36 children (16 boys, 20 girls) 6-8 years of age. We measured SI, RI and FST at rest both before and after the exercise stress test on a cycle ergometer and repeated these measurements within 5-14 days. The reproducibility of SI, RI and FST was evaluated by calculating intraclass correlation coefficients (ICC), coefficients of variation (CV%) and 95% limits of agreements. SI had a greater reproducibility after the exercise stress test than before it (CV% 4·8 versus 6·3%, ICC 0·548 versus 0·438). RI had a better ICC (0·689 versus 0·416) but a higher CV% (28·6 versus 18·7%) after the exercise stress test than before it. Relative change in response to the exercise stress test in SI (-1·5% at first visit and 0·4% at second visit) was not as dramatic as in RI (-49·3% at first visit and -46·5% at second visit). The reproducibility of FST was also better after the exercise test than before it (CV% 5·7 versus 10·0%, ICC 0·509 versus 0·503). In healthy children, the reproducibility of SI, RI and FST was relatively good, especially after the exercise stress test.

Effects of temperature on reductions in finger blood flow induced by vibration

To investigate how temperature influences changes in finger circulation induced by hand-transmitted vibration in healthy subjects, and the variability in individual response to both vibration and temperature. With two room temperatures (20 and 28°C), finger blood flow (FBF) and finger skin temperature (FST) were measured on the left middle fingers of 12 subjects at 1-min intervals during three successive 10-min periods. A 5-N static force was applied throughout the 30-min period, and sinusoidal 125-Hz vibration at 44 ms(-2) rms. (unweighted) was applied to the right hand during the second of the three 10-min periods. Before exposure to vibration, both FBF and FST were greater with the higher room temperature. Finger blood flow in the left hand reduced during vibration of the right hand. The reduction in absolute FBF differed between the two room temperatures, but the percentage reduction in FBF relative to FBF before exposure to vibration was similar. After cessation of vibration, there was continued reduction in FBF with both room temperatures. Before and after vibration exposure, the FST was correlated with FBF and the FBF and FST at 20°C were correlated with the FBF and FST at 28°C. Vibration of one hand can reduce finger blood flow and skin temperature on the unexposed hand, with the reduction dependent on temperature. The absolute reduction in FBF was greater with the higher room temperature, but the percentage reduction in FBF relative to FBF before vibration exposure was similar. Those with greater finger blood flow before vibration tend to have greater blood flow during vibration, and those with greater finger blood flow with one temperature tend to have greater blood flow with another temperature.

Hand and Finger Dexterity as a Function of Skin Temperature, EMG, and Ambient Condition

This article examines the changes in skin temperature (finger, hand, forearm), manual performance (hand dexterity and strength), and forearm surface electromyograph (EMG) through 40-min, 11 degrees C water cooling followed by 15-min, 34 degrees C water rewarming; additionally, it explores the relationship between dexterity and the factors of skin temperature, EMG, and ambient condition. Hand exposure in cold conditions is unavoidable and significantly affects manual performance. Two tasks requiring gross and fine dexterity were designed, namely, nut loosening and pin insertion, respectively. The nested-factorial design includes factors of gender, participant (nested within gender), immersion duration, muscle type (for EMG), and location (for skin temperature). The responses are changes in dexterity, skin temperature, normalized amplitude of EMG, and grip strength. Finally, factor analysis and stepwise regression are used to explore factors affecting hand and finger dexterity. Dexterity, EMG, and skin temperature fell with prolonged cooling, but the EMG of the flexor digitorum superficialis remained almost unchanged during the nut loosening task. All responses but the forearm skin temperature recovered to the baseline level at the end of rewarming. The three factors extracted by factor analysis are termed skin temperature, ambient condition, and EMG. They explain approximately two thirds of the variation of the linear models for both dexterities, and the factor of skin temperature is the most influential. Sustained cooling and warming significantly decreases and increases finger, hand, and forearm skin temperature. Dexterity, strength, and EMG are positively correlated to skin temperature. Therefore, keeping the finger, hand, and forearm warm is important to maintaining hand performance. The findings could be helpful to building safety guidelines for working in cold environments.

Enhancement of the finger cold-induced vasodilation response with exercise training

Cold-induced vasodilatation (CIVD) is a cyclical increase in finger temperature that has been suggested to provide cryoprotective function during cold exposures. Physical fitness has been suggested as a potential factor that could affect CIVD response, possibly via central (increased cardiac output, decreased sympathetic nerve activity) and/or peripheral (increased microcirculation) cardiovascular and neural adaptations to exercise training. Therefore, the purpose of this study was to investigate the effect of endurance exercise training on the CIVD response. Eighteen healthy males trained 1 h d(-1) on a cycle ergometer at 50% of peak power output, 5 days week(-1) for 4-weeks. Pre, Mid, Post, and 10 days after the cessation of training and on separate days, subjects performed an incremental exercise test to exhaustion (.VO(2peak)) and a 30-min hand immersion in 8 degrees C water to examine their CIVD response. The exercise-training regimen significantly increased .VO(2peak) (Pre: 46.0 +/- 5.9, Mid: 52.5 +/- 5.7, Post: 52.1 +/- 6.2, After: 52.6 +/- 7.6 ml kg(-1) min(-1); P < 0.001). There was a significant increase in average finger skin temperature (Pre: 11.9 +/- 2.4, After: 13.5 +/- 2.5 degrees C; P < 0.05), the number of waves (Pre: 1.1 +/- 1.0, After: 1.7 +/- 1.1; P < 0.001) and the thermal sensation (Pre: 1.7 +/- 0.9, After: 2.5 +/- 1.4; P < 0.001), after training. In conclusion, the aforementioned endurance exercise training significantly improved the finger CIVD response during cold-water hand immersion.

Relationship between Optic Nerve Head and Finger Blood Flow

To examine the relationship between optic nerve head (ONH) and finger blood flow in subjects with and without a primary vascular dysregulation (PVD). ONH blood flow and finger blood flow was measured in 15 subjects with PVD and in 24 subjects without PVD. PVD was defined as being present if it was detected in patient history as well as by nailfold capillaromicroscopy. PVD was defined as being absent if the patient history for PVD was negative and the results of nailfold capillaromicroscopy were negative. Scanning laser Doppler flowmetry (LDF) was used to measure ONH and finger blood flow. Finger temperature was measured in all subjects using a contact sensor. ONH blood flow is significantly related to finger blood flow in subjects with PVD (p<0.01), but not in subjects without a PVD. Subjects with PVD had a significantly lower finger skin temperature in comparison to those without PVD (p<0.01) The present study indicates a relationship between ONH and finger blood flow in subjects with PVD. This might be an indirect sign of a disturbed autoregulation of ocular blood flow in PVD subjects.

Sympathetic nervous function and the effect of the catechol-O-methyltransferase Val158Met polymorphism in patients with panic disorder

BackgroundSympathetic nervous function abnormalities have long been suggested to be a possible etiology of panic disorder (PD). Catechol-O-methyltransferase (COMT) affects sympathetic activities, and the COMT Val158Met polymorphism has been suggested to be related to PD. The authors examined the relationship between sympathetic nervous function and the COMT Val158Met polymorphism in PD patients. MethodsFifty-eight patients [Val/Val (51.7%) and Met allele carriers (48.3%)] and 58 age-matched normal control subjects [Val/Val (56.9%) and Met allele carriers (43.1%)] were compared in terms of finger skin temperature, which is known to be a useful marker of sympathetic nervous function. ResultsA significant COMT Val158Met polymorphism×diagnosis interaction was found. Specifically, the met allele was found to be associated with a lower skin temperature in PD patients. ConclusionThese results suggest that the COMT Met allele is related to the higher sympathetic nervous function observed in PD.

Safety at Work in Cold Environments and Prevention of Cold Stress

The questions related to safety at work in cold environments and prevention of cold stress in working life are described in this article. Working in the cold environment is more dangerous than the same type of work in a warmer climate. All researchers have concluded that the frequency of accidents/versus temperature curves follow the U-shape with the minimum near 20 degrees C. The effects of low temperature can be divided into direct, typically frostbites, and indirect, of which the indirect effects, typically slipping accidents, are more common. In improving risk management in cold conditions the risk evaluation based on existing standards is the starting point. Prevention of risks in cold environments can be done by planning of work, technical measures like heating or reduction of cooling by protective clothing, training and other measures. Local heaters, shelters against bad weather, reduction of draught are good examples of means of improving working conditions and reducing accident risks. The local IR-heaters can increase skin temperature of fingers about 7 degrees C in normal cold work. The improvement of 3 degrees C can be reached by using insulating material in the handle of tools. By using these technical improvements we can reduce the health risks but also improve work performance and even energy savings at work places.

Development of a Virtual Arm Wrestling System for Force Display Communication Analysis

The virtual arm wrestling system prototype we propose for force display communication analysis uses a 5-DOF force display system with 4 air cylinders and a force sensor we developed for virtual human affect display and interaction based on nonverbal human behavior and physiological measurement in arm wrestling. We evaluated the relationship between force display and a physiological index of peripheral finger skin temperature associated with circulation dynamics responding to forced action. We confirmed the system's effectiveness in analyzing force display communication.

Cold extremities and difficulties initiating sleep: evidence of co‐morbidity from a random sample of a Swiss urban population

Difficulties initiating sleep (DIS) can frequently occur in psychiatric disorders but also in the general population. The primary vasospastic syndrome is a functional disorder of vascular regulation in otherwise healthy subjects complaining of thermal discomfort from cold extremities (TDCE). Laboratory studies have shown a close relationship between long sleep onset latency and increased distal vasoconstriction in healthy young subjects. Considering these findings, the aims of the Basel Survey were to assess the prevalence rates for DIS and TDCE and to determine whether both symptoms can be associated in the general population. In a random population sample of Basel-Stadt, 2800 subjects (age: 20-40 years) were requested to complete a questionnaire on sleep behavior and TDCE (response rate: 72.3% in women, n = 1001; 60.0% in men, n = 809). Values of DIS and TDCE were based on questionnaire-derived scores. In addition, TDCE was externally validated in a separate group of subjects (n = 256) by finger skin temperature measurements--high TDCE values were significantly associated with low finger skin temperature. A total of 31.1% of women and 6.9% of men complain of TDCE. In contrast, prevalence rates of DIS were only slightly higher in women in comparison to men (9.3% versus 6.7%, P < 0.1). Irrespective of gender, each seventh subject complaining of TDCE had concomitant DIS and the relative risk in these subjects was approximately doubled. Therefore, a thermophysiological approach to DIS may be relevant for its differential diagnosis and its treatment.

The Influence of an Acute Dose of Aspirin on Cold-Induced Vasodilation

When the fingers are exposed to the cold there is a cyclic response between vasoconstriction and cold-induced vasodilation (CIVD) which serves to decrease and increase finger skin temperature (TSK). The exact mechanisms responsible for CIVD are not completely understood but the release of vasodilatory substances may contribute to CIVD. Aspirin (ASP) may decrease the release of nitric oxide and prostaglandins. PURPOSE: To examine the effects of an acute dose of ASP on the CIVD response during submersion of the hand in cold water. METHODS: Six subjects (5 males, 1 female; mean age: 23.0 ± 3.3 yrs) performed two experimental trials for the assessment of CIVD. During one experimental trial, subjects ingested 650 mg of ASP dissolved in 125 mL of orange juice 30 minutes prior to the trial. During the other experimental trial, subjects ingested a placebo (PL) (125 mL of orange juice). The order of the experimental trials was counter-balanced and a double-blind placebo controlled design was utilized. Each experimental trial consisted of a 30 minute baseline period (27°C air), 40 minute cold exposure (hand submersed in 5°C water), and a 15 minute recovery period (27°C air). TSK of the second and third fingers was measured continuously using thermocouples. The following variables were used to assess the CIVD response during the cold exposure: onset time (time from onset of cold exposure to increase in finger TSK), TMIN (minimum finger TSK), TMAX (maximum finger TSK), peak time (time from onset of cold exposure to TMAX), TMEAN (average finger TSK from onset time to end of cold exposure), and amplitude (TMAX - TMEAN). RESULTS: There were no differences between PL and ASP for onset time (PL = 710 ± 440, ASP = 728 ± 422 sec), TMIN (PL = 5.29 ± 0.52, ASP = 5.39 ± 0.37°C), TMAX (PL = 6.36 ± 1.13, ASP = 6.22 ± 0.88°C), peak time (PL = 1222 ± 579, ASP = 1350 ± 468 sec), TMEAN (PL = 5.79 ± 0.64, ASP = 5.80 ± 0.61°C), and amplitude (PL = 0.57 ± 0.61, ASP = 0.42 ± 0.31°C) (all P > 0.05). CONCLUSIONS: The ingestion of 650 mg of ASP had no effect on the finger TSK when the hand is submersed in 5°C cold water. These results indicate that 650 mg of ASP may not have been sufficient to inhibit the release of vasodilatory substances or, if ASP was effective in inhibiting the release of vasodilatory substances, these substances may not be involved in CIVD.

The trainability and contralateral response of cold-induced vasodilatation in the fingers following repeated cold exposure

Cold-induced vasodilatation (CIVD) is proposed to be a protective response to prevent cold injuries in the extremities during cold exposure, but the laboratory-based trainability of CIVD responses in the hand remains equivocal. Therefore, we investigated the thermal response across the fingers with repeated local cold exposure of the whole hand, along with the transferability of acclimation to the fingers of the contralateral hand. Nine healthy subjects immersed their right hand up to the styloid process in 8 degrees C water for 30 min daily for 13 days. The left hand was immersed on days 1 and 13. Skin temperature was recorded on the pads of the five fingertips and the dorsal surface of the hand. The presence of CIVD, defined as an increase in finger skin temperature of 0.5 degrees C at any time during cooling, occurred in 98.5% of the 585 (9 subjects x 5 sites x 13 trials) measurements. Seven distinct patterns of thermal responses were evident, including plateaus in finger temperature and superimposed waves. The number (N) of CIVD waves decreased in all digits of the right hand over the acclimation period (P = 0.02), from average (SD) values ranging from 2.7 (1.7) to 3 (1.4) in different digits on day 1, to 1.9 (0.9) and 2.2 (0.7) on day 13. Average (SD) finger skin temperature (T (avg)) ranged from 11.8 (1.4) degrees C in finger 5 to 12.7 (2.8) degrees C in finger 3 on day 1, and then decreased significantly (P < 0.001) over the course of the training immersions, attaining values ranging from 10.8 (0.9) degrees C in finger 4 to 10.9 (0.9) degrees C in finger 2 on day 13. In the contralateral hand, N was reduced from 2.5 to 1.5 (P < 0.01) and T (avg) by approximately 2 degrees C (P < 0.01). No changes were observed in thermal sensation or comfort of the hand over the acclimation. We conclude that, under conditions of whole-hand immersion in cold water, CIVD is not trainable and may lead to systemic attenuation of thermal responses to local cooling.

Enhancement of cold-induced vasodilatation following acclimatization to altitude

The present study evaluated the effect of high-altitude acclimatisation on the cold-induced vasodilatation (CIVD) response. A group of highly trained mountaineers (N = 9; Alpinists) were tested before and after a 3 week high-altitude Himalayan expedition (altitude ranging from 3,985 to 6,828 m). A control group (N = 7) with no mountaineering experience was tested at the same time points. During each test, subjects first immersed their hand to the styloid process in 37 degrees C water for 5 min and then in 10 degrees C water for 30 min. Upon completion of the hand immersion, the same procedure was repeated for the foot. Skin temperature of the pads of all immersed digits was measured throughout the immersion and for 10 min following the immersion. In the Alpinists, a significant increase in amplitude of CIVD and absolute maximum finger skin temperature during immersion was observed in the hand post-expedition. For the foot, peak time of CIVD was significantly shorter in the Alpinist group, and there were significant increases in minimum and maximum toe skin temperature during CIVD, mean toe skin temperature during immersion, absolute minimum and maximum toe skin temperature during immersion, and absolute amplitude during immersion. The results demonstrate a significant enhancement of the CIVD response as a consequence of a brief high altitude acclimatisation, and that these changes were especially prominent in the toes.

Effects of pressure, cold and gloves on hand skin temperature and manual performance of divers

Cold water immersion and protective gloves are associated with decreased manual performance. Although neoprene gloves slow hand cooling, there is little information on whether they provide sufficient protection when diving in cold water. Nine divers wearing three-fingered neoprene gloves and dry suits were immersed in water at 25 and 4 degrees C, at depths of 0.4 msw (101 kPa altitude adjusted) and 40 msw (497 kPa) in a hyperbaric chamber. Skin temperatures were measured at the fingers, hand, forearm, chest and head. Grip strength, tactile sensitivity and manual dexterity were measured at three time intervals. There was an exponential decay in finger and back of hand skin temperatures with exposure time in 4 degrees C water. Finger and back of hand skin temperatures were lower at 40 msw than at 0.4 msw (P < 0.05). There was no effect of pressure or temperature on grip strength. Tactile sensitivity decreased linearly with finger skin temperature at both pressures. Manual dexterity was not affected by finger skin temperature at 0.4 msw, but decreased with fall in finger skin temperature at 40 msw. Results show that neoprene gloves do not provide adequate thermal protection in 4 degrees C water and that impairment of manual performance is dependent on the type of task, depth and exposure time.

Effects of local and core body temperature on grip force modulation during movement-induced load force fluctuations

Impaired manual functioning often occurs when the hands are exposed to cold temperatures, but the underlying mechanism is not clearly understood. Tactile feedback is thought to provide important information during object manipulations in order to scale and regulate grip forces; however, topical anaesthetic-induced tactile sensation impairments may not realistically simulate the systemic neuromuscular impairment of the whole hand that could occur during cold temperature exposure. In two experiments, we studied the impact of (1) local hand cooling [thermoneutral finger skin temperature, cold (<8 degrees C)] and (2) core body temperature (thermoneutral core body temperature, pre-heated by 0.5 degrees C, pre-cooled by 0.5 degrees C) with cold hands on manual dexterity and the ability to control and co-ordinate grip forces during a cyclical load-lifting task. In Experiment 1 (n = 10), hand cooling significantly decreased Purdue Pegboard performance (P = 0.002), while increasing grip force by approximately 5 N during the cyclical load-lifting task compared to thermoneutral (P = 0.037). The temporal co-ordination of grip and load forces was unaffected by hand cooling. In Experiment 2 (n = 11), pegboard performance was impaired following hand cooling (P < 0.001), and to a greater extent when the body was pre-cooled (p < 0.001). However, neither grip force (P = 0.99) nor the temporal co-ordination of grasping and lifting forces (P = 0.85) were affected by core body temperature. These data support the existence of a robust centrally controlled feedforward system able to anticipate the dynamics of manual manipulations and accordingly regulate the temporal co-ordination of fingertip forces during object manipulation. This centrally controlled mechanism appears to differ from the mechanisms governing other aspects of manual dexterity.