Studies of the propriety of the items adopted for the special health examination of vibration hazards at present (author's transl)

Skin temperature, vibratory sense, nail press test and pain sense are customarily used as the items in the special health examination for finding vibration hazards at present. These items are measured under the condition of room temperature at 20 to 23 degrees c and after 10-minute immersion in cold water at 5 degrees C or 10 degrees C. In this report, the propriety of these items was investigated on the basis of measurements in 274 healthy chain saw operators and 294 healthy bush cutter operators. The 10-minute immersion test in cold water at 10 degrees C was adopted in this experiment. The results obtained are as follows: Skin temperatures of the chain saw and bush cutter operators did not show any significant difference by age under the condition at the room temperature, but the recovery in the subjects in the twenties was faster than in the other. Skin temperatures at the 10th minute after the 10-minute immersion test in cold water at 10 degrees C showed very wide deviations among the subjects. Vibratory senses of the aged subjects markedly lowered in comparison with those of the younger subjects. Recovery of vibratory sense after the immersion in cold water showed a tendency which is faster than that of the skin temperature. Correlation between the skin temperature and the vibratory sense at the 10th minute after the immersion was statistically significant. Most of the subjects showed the recovery time within 2 sec with the nail press test under the condition of the room temperature and at the 10th minute after the immersion. Above 95% of subjects complained pain sense with one gram weight at the measurement under the all conditions except immediately after the 10-minute immersion test. From the above results, it should be considered that the value of these measurement may be dominated by the age of the subjects and that the immersion test in cold water to the tests of vibratory sense and pain sense may not have important role in the diagnosis of vibration hazards.     

The effect of aging on the peripheral functions in farmers and chain saw operators. Part 2. Age-related changes in skin temperature and hyperemia time after pressing the nail (author's transl)

Vibration hazards which arise after exposure to mechanical vibration comprise various types of disorders, the most common of which are peripheral circulatory disturbances. It is now well recognized that aging effects all organ systems of the human body. The present study was therefore performed to assess the effects of aging on finger skin temperature and on hyperemia time after pressing the nail, both of which reflect peripheral circulatory functions. The subjects were 88 farmers and 86 chain saw operators ranging in age from 30 to 69 years, and 27 healthy persons aged 21 to 37 years as controls. Data were evaluated before and after cold water immersion tests in which the hand was immersed in 10 degrees C water for 10 minutes. The results obtained were as follows: 1) Before the test, skin temperature was negatively correlated with age, and hyperemia time was positively correlated with age in both farmers and chain saw operators but not in the case of the control subjects. 2)The skin temperature became lower, and hyperemia time grew longer with advancing age in both farmers and chain saw operators before and after the immersion tests. In comparison of the average skin temperature and hyperemia time between farmers and chain saw operators classified by age, the average skin temperature in chain saw operators was significantly lower than that in farmers, and the average hyperemia time in chain saw operators was significantly longer than that in farmers of every age group after the immersion test. The results suggest that we should take age-related changes into consideration to some degree when we evaluate the finger skin temperature and hyperemia time in diagnosing peripheral circulatory disturbances.     

Changes in cold-induced vasodilatation, pain and cold sensation in fingers caused by repeated finger cooling in a cool environment

To examine how repeated cooling of fingers with a rest pause schedule at work affects cold-induced vasodilatation (CIVD), pain and cold sensation in fingers, six healthy men aged 21 to 23 years immersed their left index fingers six times in stirred water at 10 degrees C for 10 minutes. After each cold-water immersion of the fingers, 5-minute rest pause was taken to observe the recovery process of the indicators. This cold-water immersion/rest pause test was carried out in a range of three ambient temperature conditions: 30 degrees C (warm), 25 degrees C (thermoneutral), and 20 degrees C (cool) as experienced in daily life. At the ambient temperatures of 30 degrees C and 25 degrees C, marked CIVD response occurred and the CIVD reactivity did not significantly change upon repetition of cold-water immersion. The lowered finger skin temperature also tended to recover quickly to the pre-immersion level during each post-immersion rest period. At the ambient temperature of 20 degrees C, however, the CIVD response weakened continuously upon repetition of immersion and almost disappeared during the final immersion. The recovery of finger skin temperature during each post-immersion rest was gradually delayed upon repetition of immersion. At every ambient temperature, finger pain and cold sensation induced by each cold-water immersion significantly decreased upon repetition of immersion and completely disappeared during each post-immersion rest period. Oral temperature during the experiment showed no significant change at the ambient temperatures of 25 degrees C and 30 degrees C, but it decreased significantly at the ambient temperature of 20 degrees C. These results suggest that in a cool work environment where the body core temperature is liable to decrease, repeated finger cooling may weaken CIVD reactivity and delay the recovery of finger temperature during post-immersion rest periods. In such lower ambient temperature work conditions, subjective judgements such as the decrease in finger pain and cold sensation during repeated finger cooling and the absence of them during post-immersion rest may not be reliable indicators for monitoring the risk of progressive tissue cooling and frostbite formation.     

Tests employed in Japan for the investigation of peripheral circulatory disturbances due to hand-arm vibration exposure

Tests for the investigation of peripheral circulatory function are thought, in Japan, to be of primary importance for the proper diagnosis of the hand-arm vibration syndrome. The complaints presented in connection with Raynaud's phenomenon (finger skin blanching, numbness, cold sensation, and pain in the hands) should be thoroughly assessed. In evaluating the results of skin temperature measurements and the nail compression test before and after cold provocation by immersion of the hands in cold water, seasonal and diurnal variation, as well as differences in room temperature, temperature of the cooling water, duration of cooling time, etc, must be taken into account.     

Significance of finger coldness in hand-arm vibration syndrome

Objectives To evaluate the relationship between subjective symptoms of coldness in fingers and peripheral circulation in patients with hand-arm vibration syndrome (HAVS). Methods Thirty-five male patients confirmed to have HAVS as an occupational disease took part in this study. Their mean age was 62 years (SD 5) and all were chain-saw operators exposed to vibration for an average of 25 years. Their annual health examination included the history of their daily habits (smoking, drinking, and therapeutic exercise), report of subjective symptoms such as coldness, numbness and tingling in the fingers, and a physical examination; laboratory tests consisted of skin temperature measurement, and pain and vibration perception under conditions of cold provocation. A frequently used method of cold provocation, immersion of the left hand up to the wrist in water of 10°C for 10 min, was used. Results Finger coldness was classified into 3 groups according to its severity: mild group (n=8), moderate group (n=17) and severe group (n=10). There was no significant difference in age or occupational background between the groups. A significant association was found between finger coldness and prevalence of Raynaud's pheno menon (p<001, χ²). The mean skin temperature was significantly lower with the severity of finger coldness (ANOVA, p<0.05). In the cold provocation test, there was no significant difference between skin temperature and coldness at 5 min and 10 min after immersion, though a difference was observed immediately after immersion. No significant difference was observed in the relationship between finger coldness and vibrotactile threshold before, during or after the cold provocation test. Conclusions The severity of coldness in the fingers is significantly related to skin temperature. The severity of finger coldness reflects the extent of peripheral circulatory vasoconstriction. Coldness in the fingers may be a good warning of potential problems in peripheral, circulatory function.     

Physiological methods used in Japan for the diagnosis of suspected hand-arm vibration syndrome

In the pathogenesis of hand-arm vibration syndrome, vibration affects the peripheral system, especially the circulatory, nervous, and musculoskeletal systems. Medical questionnaires, physical examinations, and laboratory tests are used to diagnose the hand-arm vibration syndrome. The laboratory tests are satisfactory diagnostic aids for detecting slight disorders of the peripheral circulatory, nervous, and musculoskeletal systems. Peripheral circulatory function tests include skin temperature measured by a thermistor under specific temperature conditions, the nail compression test, and the cold provocation test (10-min immersion in cold water at 5 or 10 degrees C). To assess peripheral nervous function, tests for the pain and vibration senses are included. Peripheral musculoskeletal function tests consist of grip strength, pinch strength and tapping counts. These physiological tests are applied in worker screening twice a year. These tests have been authorized by the Ministry of Labour since 1973. Several criteria for the tests, although not authorized, are widely used. The diagnostic implication of each separate test may be low. Consequently, some laboratory tests should be evaluated, along with medical questionnaires and physical examinations, in the diagnosis of suspected hand-arm vibration syndrome.     

Cold-stress tests involving finger skin temperature measurement for evaluation of vascular disorders in hand-arm vibration syndrome: review of the literature

Cold-stress tests are used for evaluating vascular disorders in the hand-arm vibration syndrome, and the value of such tests based on finger skin temperature measurement has been investigated. However, there is a wide difference in the test conditions among countries and researchers. Standardization of the cold-stress tests is currently under discussion within the International Organization for Standardization. We reviewed various aspects of the cold-stress tests involving finger skin temperature measurement, including water temperature, hand immersion time and other test conditions, and evaluated their diagnostic significance. Water temperature varied from 0 degrees C to 15 degrees C and hand immersion time varied from 0.5 min to 20 min. The cold-stress tests are associated with relatively severe suffering, thus, higher temperature of cold water and shorter time of immersion are desirable. To date, however, there has not been sufficient data indicating diagnostic value in a test method involving cold water at around 15 degrees C. Diagnostic value is also influenced by other test conditions, such as room temperature, season, use of ischemia during immersion. For standardization of the cold-stress test involving finger skin temperature measurement, these factors must be considered together with water temperature and immersion time.     

Development of an improved system for monitoring the peripheral circulation and its application. Part 2. Its application to the cold water immersion test in workers using vibratory tools

Using an improved system for measuring skin blood flow by the thermal clearance curve, the change of the skin blood flow in the finger (finger blood flow) of the workers using vibratory tools induced by 10 degrees C cold water immersion for 10 min was observed in order to clarify the pathogenesis of vibration-induced white finger (VWF) from the aspect of peripheral circulatory function and simultaneously to demonstrate the efficiency of the system. The subjects constituted a group of 10 workers with VWF (VWF group) and 10 healthy workers without a history of hand-arm symptoms (control group). Ages and years of exposure to vibration in the two group were almost equal. The results were as follows. 1) While the finger blood flow in the control group was remarkably decreased at 1 min after the immersion, the decrease in the VWF group was low as compared with that in the control group. This result shows that vasoconstriction just after the immersion in VWF patients is not as great as that in the control group. 2) The finger blood flow in the control group at 5 min after the immersion was increased. In contrast no increase in the VWF group was observed. These results showed that cold-induced vasodilatation (CIVD) in VWF patients diminished. 3) An increase of the finger blood flow at 1 min after stopping the immersion was observed in the VWF group. These results suggest that the property of reaction to cold in VWF patients is not excessive vasoconstriction as has been hypothesized, but the diminution of CIVD. Apart from 10 workers of VWF group, observing the change of the finger blood flow in a case in which VWF was provoked by the immersion, the author found an abnormal decrease of the finger blood flow at 5 min after the immersion. This finding supports the hypothesis that the diminution of CIVD plays an important role in VWF attack as well. Concerning the characteristics of peripheral circulatory function in VWF patients, it can therefore be considered that its reaction in VWF attack is vasospasms, while the reaction to cold is the diminution of CIVD in the non-attack phase. The cold water immersion test using the system was recognized to be useful for diagnostic examination because the estimation of finger blood flows at both measuring points, 1 min and 5 min after the immersion, could fairly well discriminate VWF patients from healthy workers.(ABSTRACT TRUNCATED AT 400 WORDS)     

A 4 degrees C-1 min method of cold water immersion test for peripheral circulatory function in fingers]

To assess the validity of a new simplified cold water immersion test (4 degrees C-1 min method) for peripheral circulatory function, comparison was made with the conventional method (10 degrees C-10 min method). These two different methods of cold immersion test were applied to 23 patients with vibration disease and 24 healthy men. Observation was made on finger skin temperature by a thermistor and complaints in the hand by a 5-step self-reported scale method every minute during the test. The patterns of recovery of skin temperature after cold immersion in each group were similar in both methods. Pain in the hand in the 4 degrees C-1 min method was less than that in the 10 degrees C-10 min method. The recovery rate at 5 min in the patients with Raynaud's phenomenon was lower than that in those without Raynaud's phenomenon in the 4 degrees C-1 min method (p < 0.01). However, no significant differences were noted in 10 degrees C-10 min method. The results suggest that the new method is feasible in detecting the response of vasodilation after immersion. In the recovery rate at 5 min after immersion, near values of the sensitivity and specificity were observed between 50% cut-off values in the 4 degrees C-1 min method and 30% value in the 10 degrees C-10 min method. Thus, the 4 degrees C-1 min method is considered to be more useful to evaluate the physiological response after cold immersion than the 10 degrees C-10 min method.     

Influence of waterproof covering on finger skin temperature and hand pain during immersion test for diagnosing hand-arm vibration syndrome

The purpose of this study was to examine the influence of waterproof covering on finger skin temperature (FST) and hand pain during immersion test for diagnosing hand-arm vibration syndrome complying with the proposal of the International Organization for Standardization (ISO/ CD14835-1, 2001) for measurement procedure. Six healthy male subjects took part in the immersion tests and immersed their both hands into water at 12 degrees C for 5 min, repeatedly with two types of waterproof covering (polyethylene and natural rubber gloves) or without hand covering (bare hands) during immersion. The FST data from middle fingers and subjective pain scores for hand pain were analyzed. Statistically significant differences in FST among three conditions were observed showing the highest FST with natural rubber gloves, followed by the FST with polyethylene gloves and the lowest with bare hands. Significant differences in pain score among three conditions were observed during immersion showing the lowest pain score with natural rubber gloves, followed by the pain score with polyethylene gloves and the highest with bare hands. Immersion test with polyethylene gloves instead of bare hands during immersion seems to be suitable for reducing subject suffering.     

Studies on the items for diagnosis of the vibration disease. Part 1. Examination of healthy workers using vibratory tools

1,215 male workers using bush cleaners in Hokkaido were examined by the method based on the notification of the Labor Standard Bureau. The results obtained from clinically normal 548 workers among them were analysed especially on the finger skin temperature, vibratory sense threshold, maximum grip strength. 1) Data of the vibratory sense threshold, maximum grip strength and endurable grip strength showed normal distributions. Data of the finger skin temperature, however, showed a skewed distribution. 2) In parallel with aging, the vibratory sense threshold increased, in other words, lowered in function, and the maximum grip strength lowered. 3) The endurable grip strength measured by the five-time repetition method decreased along with aging. 4) Values of one-tail limit of the finger skin temperature were calculated in all 548 workers, and those of the vibratory sense threshold, maximum grip strength and endurable grip strength were done in each age group. The values were compared with the already proposed criteria and discussed.     

Validity of function tests on the upper extremities in establishing a prognosis in vibration syndrome

The validity of function tests on the upper extremities as prognostic tools in vibration syndrome was evaluated over a sequence of observation periods. The subjects examined were 672 forest workers using chain saws who had had some complaints and who had shown abnormal findings in the function tests. The function tests consisted of peripheral circulatory and sensory tests, including cold provocation and motor tests of functional capacity in the upper extremities. From the results of testing, 23 variables were selected and examined by multivariate analysis. The four principal components were extracted by principal component analysis, and the factor score of the peripheral circulatory disturbances component was found to be highly correlated with the severity of VWF (Vibration-induced White Finger). The course of VWF and the nail compression test had high standard regression coefficients with the severity of vibration syndrome. The course of finger numbness, pinching power, pain threshold, skin temperature and X-ray findings in the elbow joints had high discriminant function values for the evaluation of the severity of vibration syndrome.     

A four-year follow-up study on subjective symptoms and functional capacities in workers using hand-held grinders.

Fifty-three grinders in the metal industry were re-examined 4 years after their first examination. Information about age, occupation, daily vibration exposure, drinking and smoking habits, and presence of subjective symptoms such as vibration-induced white finger (VWF), and numbness and pain in the fingers was collected during the first and second examination. Cold provocation test (10 degrees C/10 min) was also employed to evaluate disturbances in the peripheral circulatory and peripheral nerves in all subjects. The frequency-weighted vibration acceleration of various types of hand-held tools was measured. There was no subject with VWF at the first examination; however, during the course of follow-up, two cases (3.8%) of VWF with latent interval of more than 25 years were diagnosed. Prevalence of numbness in the fingers and shoulder stiffness was significantly higher at the second examination. When the prevalence of subjective symptoms was tested by the subjects' total operating time (TOT) during the 4-year follow-up period, those whose TOT was equal to or more than 2500 hours showed higher prevalence compared to the other subgroup. The paired values of recovery rate of finger skin temperature and vibration sensation threshold after the cold water immersion test were significantly different at the first and second examination. On average, the diminution of hand-grip force during the 4-year follow-up course was 7.4%; the difference being significant at 0.01 level. Significant differences in the paired data of pinching power and tapping ability could be detected. The frequency-weighted vibration acceleration of various tools was in the range of 1.1-4.6 m/s2. It was concluded that: (1) prolonged occupational exposure to the vibration of hand-held grinding tools should be considered as a risk factor causing disturbances in the hand-arm system of the operators; (2) the results of recovery rate of finger skin temperature and the vibration sensation threshold seemed to be appropriate indicators for the assessment of peripheral vascular and peripheral nerve disturbances in workers exposed to hand-arm vibration; and (3) to reduce the subjects' physical stress, attention should be paid to ergonomic factors.     

Factors influencing autonomic nervous function during cold-water immersion test in patients with hand–arm vibration syndrome

OBJECTIVES: Factors influencing autonomic nervous function in patients with hand-arm vibration syndrome (HAVS) in response to cold-water immersion test with different water temperatures and immersion times were investigated in the summer and winter seasons. METHODS: Fourteen HAVS patients with vibration-induced white finger (VWF) and 14 healthy control subjects individually age-matched to the patients consented in writing and participated in this study. Patients and controls immersed their left hands in water at 10 degrees C for 10 min and at 15 degrees C for 3 min in summer and in winter in a room with temperature maintained at 21+/-1 degrees C. Electrocardiographic (ECG) data were recorded during the test period and the R-R intervals were analyzed with a fast Fourier transformation (FFT) program. Percentage of very low frequency (VLF%; indicator of both sympathetic and parasympathetic nervous function, and function of rennin-angiotensin system), low frequency (LF%; indicator of both sympathetic and parasympathetic nervous function), high frequency (HF%; indicator of parasympathetic nervous function), and LF/HF ratio (indicator of sympathetic nervous function) were calculated. The results by three-way analysis of variance (ANOVA) were reported elsewhere. In the present study, repeated measures ANOVA was used to re-analyze the factors of data measurement time (time factor) and group (group factor), and their interaction for each test method (water at 10 degrees C for 10-min immersion time; water at 15 degrees C for 3-min immersion time) in summer and winter. RESULTS: The HF% of HAVS patients tended to be lower than that of healthy controls throughout the cold-water immersion tests except for during tests involving water at 10 degrees C for 10-min immersion in summer. The group factor for HF% was statistically significant with an exception during the test involving water at 10 degrees C and 10-min immersion time in summer. The time factor for HF% was statistically significant with an exception during the test involving water at 15 degrees C and 3-min immersion time in winter. CONCLUSIONS: The findings of the present study indicated lower cardiac parasympathetic activity in HAVS patients than in healthy controls, especially in winter. The response of the autonomic nervous system to cold stimulation was to some extent more clearly observed during the immersion test with water at 10 degrees C and 10-min immersion time than during the immersion test with water at 15 degrees C and 3-min immersion time. The results revealed by three-way analysis in a previous study were similar to those in the present study with data analysis by repeated measures ANOVA.     

Intra-individual variation of skin temperature recovery rate after cold water immersion among Japanese bush-cutter operators

Recovery rates of skin temperature after cold water immersion tests and other measurements were recorded from 1978 to 1989 to assess the effects of vibration due to the use of bush-cutters on the health of 42 road-maintenance workers having an average age of 51.7 years. Their work and health conditions were controlled and checked systematically, and the incidence of white finger in 1989 was 2%. The recovery rate as well as the initial skin temperature was influenced greatly by ambient temperature and thus direct assessment of the changes in recovery rate had little value. The intra-individual variation in recovery rates among 6 examinations ranged widely from 6.7 to 55.7%. Subjects with large variation in the recovery rate showed better results in recovery rate, skin temperature, and vibratory sensation than those with little variation. Individuals with large variation tend to respond well to changes in ambient temperature and to suspension and resumption in the use of bush-cutters, indicating the elasticity of their peripheral circulatory system.     

Preliminary study on the assessment of peripheral vascular response to cold provocation in workers exposed to hand-arm vibration using laser Doppler perfusion imager

Measurements of changes in finger skin blood flow with laser Doppler perfusion imaging (LDPI) in response to cold provocation test (10 degrees C, 10 min) were performed in 12 men suffering from vibration induced white finger (VWF) and 13 exposed controls. The mean perfusion values in both groups reduced markedly as a result of immersion of the hand in cold water. In the controls, however, the mean value increased gradually until the end of the cold provocation, while that in the VWF subjects remained at the lowest level. After removal of the hand from the cold water, the skin blood perfusion in the controls recovered rapidly and nearly reached the baseline value. In the VWF subjects, it had a slight increase immediately following the cold immersion but no tendency to rise as the time span increased. Analysis of covariance controlling for possible confounders revealed that the VWF subjects had significantly lower perfusion values compared to the controls in the last several minutes of the cold provocation and the following recovery. These findings suggest that the LDPI technique enables visualizing and quantifying the peripheral vascular effects of cold water immersion on the finger skin blood perfusion and thus has the potential of providing more detailed and a&curate information that may help detect the peripheral circulatory impairment in the fingers of vibration-exposed workers.     

Longitudinal study on factors related to the course of vibration-induced white finger

 Follow-up surveys were conducted in 1982 and 1988 to investigate factors affecting the course of vibration-induced white finger (VWF). Subjects were 353 patients, aged 40 to 70 at the start of the 1982 survey, who were receiving treatment for hand-arm vibration syndrome. Between 1982 and 1988, the attacks of VWF decreased, while numbness and pain in the hand changed slightly. Finger skin temperature showed a tendency to increase, but recovery time in nail compression tests was unchanged. Vibration perception threshold and grasping power tended to become worse. Of the 177 patients with VWF in 1982, 55 (31%) had no VWF in 1988. The improvement in VWF depended on its severity assessed by the frequency of attacks, the extent of the affected finger phalanges and the Stockholm vascular (V) stage at the start of the 1982 survey. The improvement was observed in 46% of the 1V (mild) stage cases, against only 17% of the 3V (severe) stage cases. Patients in the 2V (moderate) and 3V stages had lower finger skin temperature than those without VWF (the 0V stage). Patients with milder VWF seemed more likely to improve. Continued use of vibratory tools was found to be an unfavourable factor for improvement of VWF. Age, smoking and drinking habits, and medical complications showed no significant effects on the course of VWF. Received: 26 February 1996/Accepted: 2 May 1996     

Vibration syndrome among forestry workers. Subjective symptoms and diagnostic norm

Three hundred fourteen male forestry workers using vibrating tools were analyzed to evaluate the relationship among 11 items of the special examinations for the diagnosis of vibration syndrome and the relationship between the items and 13 subjective symptoms. The following results were obtained: Age of the workers had the strongest relationship to the grip strength. However, it showed less strong relationship with other items, such as the threshold of pain sense and that of vibration sense, and the degree of Raynaud's phenomenon (number of fingers affected). Working time in years with vibrating tools showed statistically significant correlations with the threshold of pain sense, that of vibratory sense, and with the degree of Raynaud's phenomenon. The threshold of pain sense, that of vibratory sense, and the degree of Raynaud's phenomenon correlated with each other but not with the skin temperature nor the recovery time of blood flow in the finger nail-beds. The rise of pain threshold exhibited the strongest association with the subjective symptoms. Vibratory sense threshold at 250 Hz also showed similar association with the latter. The skin temperature and the recovery time of blood flow had no association with any complaints except for gastric disorders. The grip strength, only when extremely lowered, was associated with the rise of ratio of complaints, i.e. percentage of the number of workers who complain among all the workers. The age was associated in general with the decreased ratio of complaints except for muscle weakness in arms and forgetfulness.     

A study of neurophysiological measurements and various function tests on workers occupationally exposed to vibration

Summary Seventy male air grinder operators and 72 age-matched control workers were examined. Both groups of workers worked in the warm climate (20°–33°C) of southern Taiwan. None of the workers had symptoms of white fingers. The investigation program comprised: (1) case history, (2) physical examination, (3) determination of maximal motor conduction velocity, proximal and distal sensory conduction velocity (NCV) of the median and ulnar nerves of the right upper extremity, (4) measurement of skin temperature, nail press test, pain threshold and vibratory sense threshold of the upper extremities, and (5) testing of the motor function. The dose-effect correlation between the NCV, various function tests and total operating time (TOT) was performed by multiple stepwise regression analyses. The regression analyses revealed a statistically significant correlation (dose/effect) between the six NCV, vibratory sense threshold, pain threshold and age, as well as TOT.     

冬泳运动员的冷适应水平

我国北方冬泳运动员经常接触的冷水环境,为一般人日常生活中绝难经历的严酷冷应激条件。在手指浸泡冰水的试验中,冬泳者指温高、血管舒张反应比对照组较早出现。尽管其在冷中有较强的保持肢端温度的能力,但4h的全身冷暴露过程中,其体心温度及股皮温却低于对照组,较少发生寒战,痛感轻,代谢率也不似对照组那样地明显增强。表明冬泳者属于低体温——隔热型的冷适应。