Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SHIVERING”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed2000

A comparison of urapidil, clonidine, meperidine and placebo in preventing postanesthetic shivering.

UNLABELLED: This placebo-controlled study was performed to evaluate the efficacy of urapidil compared with clonidine and meperidine in preventing postanesthetic shivering, which is common after anesthesia administration and may be very distressing. We studied 120 patients undergoing elective abdominal or orthopedic surgery under standardized general anesthesia. After surgery, patients were randomly assigned to one of four groups (each group n = 30) using a double-blinded protocol: Group A received 0.2 mg/kg urapidil; Group B, 3 microg/kg clonidine; Group C, 0.4 mg/kg meperidine; and Group D, saline 0.9% as placebo. Postanesthetic shivering was scored by using a five-point scale. Clonidine and meperidine significantly reduced the incidence and the severity of shivering in comparison with placebo, whereas there were no significant differences between the urapidil and placebo groups. Both clonidine and meperidine caused a significantly prolonged emergence time (13.4 +/- 5.8 and 13. 3 +/- 5.0 min, respectively) compared with placebo (10.4 +/- 5.3 min) and urapidil (11.4 +/- 2.9 min). We confirmed that both clonidine and meperidine are effective in preventing postanesthetic shivering, whereas urapidil, in our setting and dosage, was not effective. Patients who received clonidine or meperidine had a prolonged emergence time. In the dosage used, urapidil seems to be unable to prevent postanesthetic shivering. IMPLICATIONS: Shivering (irregular muscle activity) is common after surgery and anesthesia. This study compared urapidil (an antihypertensive drug) as a prophylaxis with two established antishivering drugs (meperidine and clonidine) and placebo. In the dosage used, we were unable to show a significant benefit of urapidil.

Adult↗
PubMed1997

Dexmedetomidine does not alter the sweating threshold, but comparably and linearly decreases the vasoconstriction and shivering thresholds.

BACKGROUND: Clonidine decreases the vasoconstriction and shivering thresholds. It thus seems likely that the alpha2 agonist dexmedetomidine will also impair control of body temperature. Accordingly, the authors evaluated the dose-dependent effects of dexmedetomidine on the sweating, vasoconstriction, and shivering thresholds. They also measured the effects of dexmedetomidine on heart rate, blood pressures, and plasma catecholamine concentrations. METHODS: Nine male volunteers participated in this randomized, double-blind, cross-over protocol. The study drug was administered by computer-controlled infusion, targeting plasma dexmedetomidine concentrations of 0.0, 0.3, and 0.6 ng/ml. Each day, skin and core temperatures were increased to provoke sweating and then subsequently reduced to elicit vasoconstriction and shivering. Core-temperature thresholds were computed using established linear cutaneous contributions to control of sweating, vasoconstriction, and shivering. The dose-dependent effects of dexmedetomidine on thermoregulatory response thresholds were then determined using linear regression. Heart rate, arterial blood pressures, and plasma catecholamine concentrations were determined at baseline and at each threshold. RESULTS: Neither dexmedetomidine concentration increased the sweating threshold from control values. In contrast, dexmedetomidine administration reduced the vasoconstriction threshold by 1.61 +/- 0.80 degrees C x ng(-1) x ml (mean +/- SD) and the shivering threshold by 2.40 +/- 0.90 degrees C x ng(-1) x ml. Hemodynamic responses and catecholamine concentrations were reduced from baseline values, but they did not differ at the two tested dexmedetomidine doses. CONCLUSIONS: Dexmedetomidine markedly increased the range of temperatures not triggering thermoregulatory defenses. The drug is thus likely to promote hypothermia in a typical hospital environment; it is also likely to prove an effective treatment for shivering.

Adrenergic alpha-Agonists↗
PubMed2001

Shiver suppression using focal hand warming in unanesthetized normal subjects.

BACKGROUND: A decrease of 1 or 2 degrees C in core temperature may provide protection against cerebral ischemia. However, during corporeal cooling of unanesthetized patients, the initiation of involuntary motor activity (shiver) prevents the reduction of core temperature. The authors' laboratory previously showed that focal facial warming suppressed whole-body shiver. The aim of the current study was to determine whether the use of hand warming alone could suppress shiver in unanesthetized subjects and hence potentiate core cooling. METHODS: Subjects (n = 8; healthy men) were positioned supine on a circulating water mattress (8-15 degrees C) with a convective-air coverlet (14 degrees C) extending from their necks to their feet. A dynamic protocol was used in which focal hand warming was used to suppress involuntary motor activity, enabling noninvasive cooling to decrease core temperatures. The following parameters were monitored: (1) heart rate; (2) blood pressure; (3) core temperature (rectal, tympanic); (4) cutaneous temperature and heat flux; (5) subjective shiver level (SSL scale 0-10) and thermal comfort index (scale 0-10); (6) metabolic data (n = 6); and (7) electromyograms. RESULTS: During cooling without hand warming, involuntary motor activity increased until it was widespread. After subjects reported whole-body shiver (SSL > or = 7), applied hand warming, in all cases, reduced shiver levels (SSL < o r= 3), decreased electromyographic root mean square amplitudes, and allowed core temperature to decrease from 37.0 +/- 0.2 to 35.9 +/- 0.5 degrees C (measured rectally). CONCLUSIONS: Focal hand warming seems to be valuable in minimizing or eliminating the need to suppress involuntary motor activity pharmacologically when it is desired to induce or maintain mild hypothermia; it may be used in conjunction with facial warming or in cases in which facial warming is contraindicated.

Adult↗
PubMed1994

The effect of head covering on rewarming and shivering in cardiac surgical patients.

In hypothermic postoperative cardiac surgical patients, heat loss from the head may interfere with rewarming and cause shivering. This study investigated the effect of head covering on rewarming rate and shivering during post-operative rewarming. The sample included 19 experimental and 21 control subjects. The heads of experimental subjects were wrapped with two terry cloth towels until urinary bladder temperature (UBT) reached 37 degrees C. Admission UBTs were mildly hypothermic (34.6 degrees C to 36.70 C). Four experimental and six control subjects shivered. There were no significant differences (P < .05) in the incidence of shivering (Yates' chi 2 = 0.33; P = 0.855). After controlling significant differences between groups in height and body surface area with analysis of covariance, there were no significant differences in rewarming rate (F = 3.270; P = .079). Shiverers were slightly colder (mean, 36.13 degrees C; t = 1.768; P = .085) on admission to the cardiac surgical intensive care unit and had significantly greater heat gain (t = -2.091, P = .043) than nonshiverers. Conclusions about the effect of head covering on shivering could not be made because of small sample size. Failure to demonstrate a significant difference in rewarming rate is due to the effects of mildly hypothermic admission UBTs on the mathematical calculation of rewarming rate and on the small sample size.

Aged↗
PubMed1995

The effect of different end-tidal volatile agent and carbon dioxide concentrations upon the incidence of postoperative shivering.

Sixty patients (47 female) undergoing surgical excision of three or more wisdom teeth were randomly allocated into three groups with differing end-tidal carbon dioxide and volatile agent concentrations during maintenance of anaesthesia. The anaesthetic techniques employed were identical in all other respects. All patients were observed for 10 min after arrival in the recovery area to assess the presence and severity of shivering, axillary temperature and oxygen saturation. There were no significant differences in axillary temperatures between groups or between shivering and non-shivering patients, although there was a significant difference (p = 0.001) in duration of anaesthesia between shivering and non-shivering patients. There was no significant difference between groups with respect to the incidence of shivering (p = 0.96).

Adult↗
PubMed1997

The minimum effective doses of pethidine and doxapram in the treatment of post-anaesthetic shivering.

This study was designed to find the minimum effective doses of doxapram and pethidine to stop post-anaesthetic shivering. Two hundred and twenty healthy patients who shivered following routine surgery were allocated randomly to receive one of 10 doses of doxapram (0.18, 0.23, 0.29, 0.35, 0.41, 0.47, 0.7, 0.93, 1.17 and 1.4 mg.kg-1), one of five doses of pethidine (0.12, 0.18, 0.23, 0.29 and 0.35 mg.kg-1) or saline. Probit analysis demonstrated that the number of patients who stopped shivering with doxapram was independent of the amount of drug given in this dose range. The lowest dose of doxapram (0.18 mg.kg-1) was significantly more effective than placebo (p < 0.01). For pethidine there was a dose-dependent effect on shivering to a maximum of 95% of patients successfully treated with 0.35 mg.kg-1. We conclude that 0.35 mg.kg-1 of pethidine is the minimum dose required to treat post-anaesthetic shivering effectively. We also conclude that 0.18 mg.kg-1 of doxapram is as effective as 1.4 mg.kg-1 in the treatment of post-anaesthetic shivering. Further study is required to find the minimum effective dose of doxapram.

Adolescent↗
PubMed1995

Control of post anaesthetic shivering with nefopam hydrochloride in mildly hypothermic patients after neurosurgery.

Postoperative shivering may be prevented by maintaining normothermia intraoperatively or it may be treated using specific drugs. The aim of this study was to compare the efficacy of nefopam hydrochloride (nefopam) to that of clonidine and meperidine in patients undergoing elective neurosurgical procedures. Three groups of patients were included in the study. Patients in group A (60) received i.v., at random, 20 mg of nefopam, 50 mg of meperidine or 150 micrograms of clonidine in the immediate postoperative period. The incidence of shivering and the time at which shivering ceased were noted, along with central temperature and main haemodynamic changes. Group B (20) received i.v., at random, either 10 mg of nefopam or saline before awakening from anaesthesia. The effects of nefopam on central temperature, oxygen consumption (Vo2), carbon dioxide production (VcO2), basal metabolic rate (BMR) and energy expenditure (EE) were investigated. Group C (10) received i.v. 20 mg of nefopam during surgery: cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP) and electroencephalogram (EEG) were monitored. In group A nefopam stopped shivering in 95% of patients when compared to meperidine and clonidine, which were effective in 32% and 40% of patients respectively. In group B, only 10% of patients receiving nefopam had postoperative shivering, Vo2, VcO2 and EE were significantly lower in patients treated with nefopam than those in the control group. No changes in CSFP, CPP or EEG were observed in group C. In conclusion, nefopam seems to be more effective than clonidine or meperidine in quickly suppressing shivering, without producing significant adverse reactions.

Adult↗
PubMed1999

Misoprostol dose-related shivering and pyrexia in the third stage of labour. WHO Collaborative Trial of Misoprostol in the Management of the Third Stage of Labour.

OBJECTIVE: To select the misoprostol dose to be used in a large multicentre randomised trial comparing misoprostol with oxytocin in the routine management of the third stage of labour. DESIGN: Randomised pilot trial, double-blinded with the use of double placebos. SETTING: Two of the nine hospitals that will participate in the main multicentre trial. The hospitals were located in Johannesburg, South Africa and Khon Kaen, Thailand. POPULATION: Women during second stage of labour about to be delivered vaginally. METHODS: The trial had three arms: misoprostol 400 microg versus misoprostol 600 microg versus intramuscular oxytocin 10 IU. Each group received an injection and three tablets immediately after the birth of the baby. MAIN OUTCOME MEASURES: Shivering and pyrexia rates were the main outcome measures. Data on other side effects and characteristics of the third stage of labour were also collected. Side effects were noted as none, mild, moderate or severe. RESULTS: Both shivering and pyrexia (temperature > 38 degrees C) were most common in the 600 microg misoprostol group (28% and 7.5% for shivering and pyrexia, respectively) compared with 400 microg misoprostol (19% and 2%), and the oxytocin group (12.5% and 3%). The increase in shivering in the misoprostol 600 microg group was due primarily to a higher rate of moderate shivering. None of the women had a temperature > 40 degrees C. There were no increases in severe side effects and other adverse events in the misoprostol 600 microg group. CONCLUSIONS: When used in the management of the third stage of labour oral misoprostol is associated with an increase in the rate of moderate shivering and pyrexia which seems to be dose-related. Based on the results of this pilot trial, the Steering Committee has decided to use 600 microg misoprostol in the main trial, comparing it with oxytocin, in order to achieve higher effectiveness.

Adult↗
PubMed1993

Control of shivering and heart rate in incubating bantam hens upon sudden exposure to cold eggs.

To distinguish shivering released by cooling of the brood patch from shivering released by low core temperature, incubating bantam hens were exposed to water perfused eggs. Responses to a period of egg cooling were compared to the recovery period after egg temperature had been returned to 40 degrees C, but cloacal temperature (Tb) still was low. At an ambient temperature (Ta) of 23 degrees C and exposure of the hens to between two and eight eggs cooled to 10-35 degrees C (series 1), electromyographic (EMG) activity of musculus iliotibialis increased rapidly with an occasional overshoot, and was higher during egg cooling than during recovery. This hysteresis in EMG activity and Tb was weakly correlated to egg temperature and clutch size. Heart rate (HR) showed an almost parallel increased to shivering except that a maximum HR was reached at high shivering intensities. These responses were also present at a Ta of 37 degrees C when the hens were slightly hyperthermic before exposure to eight eggs at 20 degrees C (Series 2). At the highest starting Tbs EMG activity increased linearly after a drop in Tb. Shivering in m. pectoralis showed a lower threshold Tb and lower activity than m. iliotibialis during egg cooling, and immediately ceased at the end of egg cooling. Total body thermosensitivity estimated from the recovery periods at low and high Ta was -9.7 and -6.4 W kg-1 degrees C-1, respectively. It is concluded that shivering in incubating birds warming cold eggs probably is stimulated both by peripheral and central thermoreceptors. The peripheral component shows phasic properties typical for skin receptors.

Acclimatization↗
PubMed1994

Hypothalamic network for thermoregulatory shivering.

Warming one side of a rat's preoptic area and anterior hypothalamus (POAH) suppresses shivering on both sides of the body, and the present study evaluated the extent to which signals mediating this suppression cross the midline within and below the POAH. Hind paw shivering during unilateral POAH thermal stimulation was measured for rats in which the POAH had been midsagittally transected and for rats in which one side of the hypothalamus had been coronally transected just caudal to the POAH. In midsagittally transected rats, unilateral warming on either side of the POAH suppressed shivering equally on both sides of the body. In unilaterally transected rats, POAH warming on the transected side did not affect shivering, but warming the intact side suppressed shivering equally on both sides of the body. When a unilateral transection of only the lateral part of the hypothalamus included the medial forebrain bundle, the effect was the same as that of a unilateral transection of the whole hypothalamus. These results indicate that no information controlling shivering is exchanged between the left and right POAH and that efferent signals from the POAH, descending through the medial forebrain bundle, cross the midline somewhere below the hypothalamus to innervate both sides of the body equally.

Animals↗
PubMed1995

Poly I:C-induced fever elevates threshold for shivering but reduces thermosensitivity in rabbits.

Shivering threshold and thermosensitivity were determined in six conscious rabbits at ambient temperature (Ta) 20 and 10 degrees C before and at six different times after saline injection (0.15 ml iv) and polyriboinosinic-polyribocytidylic acid (poly I:C)-induced fever (5 micrograms/kg iv). Thermosensitivity was calculated by regression of metabolic heat production (M) and hypothalamic temperature (Thypo) during short periods (5-10 min) of square-wave cooling. Heat was extracted with a chronically implanted intravascular heat exchanger. Shivering threshold was calculated as the Thypo at which the thermosensitivity line crossed resting M as measured in afebrile animals at Ta 20 degrees C. There were negligible changes in shivering threshold and thermosensitivity in saline-injected rabbits. In the febrile animals, shivering threshold generally followed the shape of the biphasic fever response. At Ta 20 degrees C, shivering threshold was higher than regulated Thypo during the initial rising phase of fever and was lower during recovery. At Ta 10 degrees C the shivering thresholds were always higher than regulated Thypo except during recovery. Thermosensitivity was reduced by 30-41% during fever.

Animals↗
PubMed1987

Hypoxia-induced changes in shivering and body temperature.

Experiments were carried out on conscious cats to evaluate the general characteristics and modes of action of hypoxia on thermoregulation during cold stress. Intact and carotid-denervated (CD) conscious cats were exposed to ambient hypoxia (low inspired O2 fraction) or CO hypoxia in prevailing laboratory (23-25 degrees C) or cold (5-8 degrees C) environments. In the cold, both groups promptly decreased shivering and body temperature when exposed to either type of hypoxia. Small increases in CO2 concentration reinstituted shivering in both groups. At the same inspired concentration of O2, CD animals decreased shivering and body temperature more than intact cats. While this difference resulted, in part, from a lower alveolar PO2 in CD cats, a difference between intact and CD cats was apparent when the two groups were compared at the same alveolar PO2. During more prolonged hypoxia (45 min), shivering returned but did not reach normoxic levels, and body temperature tended to stabilize at a hypothermic value. Exposure to various levels of hypoxia produced graded suppression of shivering, with the result that the change in body temperature varied directly with inspired O2 concentration. Hypoxia appears to act on the central nervous system to suppress shivering and sinus nerve afferents appear to counteract this direct effect of hypoxia. In intact cats, this counteraction appears to be sufficient to maintain body temperature under hypoxic conditions at room temperature but not in the cold.

Animals↗
PubMed2003

Neither arm nor face warming reduces the shivering threshold in unanesthetized humans.

BACKGROUND AND PURPOSE: Hand warming and face warming, combined with inhalation of heated air, are reported to suppress shivering. However, hand or face temperature contributes only a few percent to control of shivering. Thus, it seems unlikely that manipulating hand or facial skin temperature alone would be sufficient to permit induction of therapeutic hypothermia. We tested the hypothesis that focal arm (forearm and hand) warming or lower facial warming, combined with inhalation of heated and humidified gas, only minimally reduces the shivering threshold (triggering core temperature). METHODS: We studied 8 healthy male volunteers (18 to 40 years of age) on 3 days: (1) control (no warming), (2) arm warming with forced air at approximately 43 degrees C, and (3) face warming with 21 L/min of air at approximately 42 degrees C at a relative humidity of 100%. Fluid at approximately 4 degrees C was infused via a central venous catheter to decrease tympanic membrane temperature 1 degrees C/h to 2 degrees C/h; mean skin temperature was maintained at 31 degrees C. A sustained increase in oxygen consumption quantified the shivering threshold. RESULTS: Shivering thresholds did not differ significantly between the control (36.7+/-0.1 degrees C), arm-warming (36.5+/-0.3 degrees C), or face-warming (36.5+/-0.3 degrees C; analysis of variance, P=0.34) day. The study was powered to have a 95% probability of detecting a difference of 0.5+/-0.5 degrees C (mean+/-SD) between control and either of the 2 treatments at alpha=0.05. CONCLUSIONS: Focal arm or face warming did not substantially reduce the shivering threshold in unanesthetized volunteers. It thus seems unlikely that these nonpharmacological modalities will substantially facilitate induction of therapeutic hypothermia.

Adolescent↗
PubMed2005

Doxapram only slightly reduces the shivering threshold in healthy volunteers.

We determined the effects of doxapram on the major autonomic thermoregulatory responses in humans. Nine healthy volunteers were studied on 2 days: control and doxapram (IV infusion to a plasma concentration of 2.4 +/- 0.8, 2.5 +/- 0.9, and 2.6 +/- 1.1 microg/mL at the sweating, vasoconstriction, and shivering thresholds, respectively). Each day, skin and core temperatures were increased to provoke sweating, then reduced to elicit peripheral vasoconstriction and shivering. We determined the sweating, vasoconstriction, and shivering thresholds with compensation for changes in skin temperature. Data were analyzed with paired t-tests and presented as mean +/- sd; P < 0.05 was considered statistically significant. Doxapram did not change the sweating (control: 37.5 degrees +/- 0.4 degrees C, doxapram: 37.3 degrees +/- 0.4 degrees C; P = 0.290) or the vasoconstriction threshold (36.8 degrees +/- 0.7 degrees C versus 36.4 degrees +/- 0.5 degrees C; P = 0.110). However, it significantly reduced the shivering threshold from 36.2 degrees +/- 0.5 degrees C to 35.7 degrees +/- 0.7 degrees C (P = 0.012). No sedation or symptoms of panic were observed on either study day. The observed reduction in the shivering threshold explains the drug's efficacy for treatment of postoperative shivering; however, a reduction of only 0.5 degrees C is unlikely to markedly facilitate induction of therapeutic hypothermia as a sole drug.

Adult↗
PubMed1982

Inhibition of shivering as a cause of metabolic suppression with norepinephrine in warm- and cold-acclimated rats.

The metabolic response of warm-acclimated (25 degrees C for 4 weeks) and cold-acclimated (5 degrees C for 4 weeks) rats to infused norepinephrine (NE) (0.5-4 micrograms/(kg.min)) was measured at an ambient temperature of 13 degrees C, either before or after sinoaortic denervation. In warm-acclimated rats, vigorous shivering consistently occurring at 13 degrees C was greatly inhibited by NE in a dose of 2-4 microgram/(kg.min). After sinoaortic denervation, no such inhibition of shivering was observed. In cold-acclimated rats, NE did not suppress but increased heat production at this temperature, no visible shivering being noticed. Phenylephrine, a alpha-adrenergic stimulant, increased blood pressure and decreased heart rate to the same extent in both groups of rats at this temperature. NE suppressed heat production even in cold-acclimated rats at -5 degrees C, where the animals exhibited shivering. These results indicated that NE infusion inhibits shivering via the sinoaortic baroreceptor reflex, in both warm-acclimated and cold-acclimated rats. The non-occurrence of metabolic suppression in cold-acclimated rats after norepinephrine infusion in the 13 degrees C environment may be due to an absence of shivering which is suppressed at this temperature.

Acclimatization↗
PubMedDate not supplied

Control of febrile shivering during amphotericin B therapy.

"Rigors" of febrile shivering often complicate therapy with amphotericin B (AmB) in immunosuppressed patients with cancer. Violent muscle contractions cause physical and emotional distress as well as dread of future therapy. This experimental study tested the effectiveness of a nursing measure in 20 hospitalized adult patients with cancer. In addition, the effects of shivering on myocardial oxygen consumption were studied. Based on Abbey's Model of Nursing Action, wraps of terry cloth toweling were applied to extremities to protect dominant skin sensors against heat loss. Patients with wrapped extremities had shorter, less severe shivering episodes than controls (p = 0.04) and required less meperidine for shivering suppression (p = 0.04). Shivering significantly elevated myocardial oxygen consumption, reflected in the rate pressure product (RPP), above pre- or post-shivering levels (p less than 0.0001). The study reflects first-year findings of a federally funded project.

Adult↗
PubMed1988

Amphotericin B-induced shivering in patients with cancer: a nursing approach.

Shivering is a common and distressful reaction associated with administration of amphotericin B, a systemic antifungal agent. Shivering occurs as a result of the drug's intrinsic pyrogenicity, and thus resembles febrile shivering. This heat loss phenomenon has metabolic as well as psychologic costs. The intervention approach to amphotericin B-induced shivering includes reporting the phenomenon, restoring lost heat, modifying the rate of heat loss, altering the physiologic determination of heat loss, and giving drugs to suppress shivering. Specific suggestions for interventions are discussed. Supportive care of the patient with cancer who is receiving this drug is briefly mentioned as it relates to thermoregulatory principles. Possible areas of future inquiry into shivering suppression are mentioned.

Amphotericin B↗
PubMed1986

Power spectral analysis of the surface electromyogram during shivering.

The purpose of this study was to describe the frequency content of the electromyogram (EMG) recorded during shivering and determine if the EMG power spectrum changed as a function of the shivering duration. Six semi-nude males were exposed to cold air (5 degrees C, 20% rh) for 80 min while quietly sitting. Rectal (Tre) and mean skin (Tsk) temperatures were recorded. Shivering of the masseter muscle was determined using bipolar surface electrodes. The EMG was amplified, recorded, and subsequently digitized at 2048 Hz. The power spectrum was calculated from eight serial 0.25s EMG samples by Fourier analysis from a frequency of 4 through 480 Hz. The eight power spectra were averaged and centroid frequency (fc) calculated. During the first 10 min of exposure, Tsk rapidly dropped from 32.6 +/- 1.6 to 26.2 +/- 1.3 degrees C, then slowly declined reaching 22.5 +/- 0.7 degrees C after 80 min. Tre rose from 37.1 +/- 0.1 to 37.4 +/- 0.1 degrees C, declining after 40 min to 37.2 +/- 0.1 degrees C. Shivering was observed within 5 min after entering the cold chamber. EMG activity after 10 min exhibited an fc of 177.2 +/- 6.2 Hz. When power was integrated over 60 Hz bandwidths, the predominant frequency band of the EMG power spectrum was 60-120 Hz. Although shivering intensity increased with time, the EMG power spectrum exhibited no significant changes. These results suggest that the EMG power spectrum during shivering did not exhibit changes characteristic of muscle fatigue or muscle cooling during the 80-min cold air exposure.

Adult↗