SIMULTANEOUS EXPERIMENTAL ACCLIMATIZATION TO HEAT AND COLD IN MAN

A 32-day long fieldwork in Antarctica improves heat tolerance during physical exercise

We evaluated the influence of a 32-day camping in Antarctica on physical performance and exercise-induced thermoregulatory responses. In Brazil, before and after the Antarctic camping, the volunteers performed an incremental exercise at temperate conditions and, two days later, an exercise heat stress protocol (45-min running at 60% of maximum aerobic speed, at 31°C and 60% of relative humidity). In Antarctica, core temperature was assessed on a day of fieldwork, and average values higher than 38.5°C were reported. At pre- and post-Antarctica, physiological (whole-body and local sweat rate, number of active sweat glands, sweat gland output, core and skin temperatures) and perceptual (thermal comfort and sensation) variables were measured. The Antarctic camping improved the participants' performance and induced heat-related adaptations, as evidenced by sweat redistribution (lower in the chest but higher in grouped data from the forehead, forearm, and thigh) and reduced skin temperatures in the forehead and chest during the exercise heat stress protocol. Notwithstanding the acclimatization, the participants did not report differences of the thermal sensation and comfort. In conclusion, staying in an Antarctic camp for 32 days improved physical performance and elicited physiological adaptations to heat due to the physical exertion-induced hyperthermia in the field.

Repeated Dry Sauna Therapy Improves Quality of Life in Obese Korean People

Background

Dry sauna treatments improve the quality of life for chronic pain, congestive heart failure, and type 2 diabetes patients. This study aimed to determine whether dry sauna therapy improved the quality of life of obese people.

Methods

A total of 38 consecutive participants aged over 20 years with a body mass index of ≥25 kg/m² were recruited for the study. The participants were treated with a 90°C dry sauna for 15 minutes, twice daily for 4 consecutive days. To assess the quality of life, all participants completed the 5 level EQ-5D questionnaires and the EQ-Visual Analog Scale. Study parameters were measured on the same day prior to commencing the sauna sessions in a fasted state and 2 days after the last sauna session.

Results

The average age was 62.3±9.5 years; 84.2% of the participants were female. The mean body mass index was 28.5±2.4 kg/m². Dry sauna significantly improved the mean 5 level EQ-5D index scores from 0.83±0.12 to 0.89±0.11 and increased the mean EQ-Visual Analog Scale from 79.0±15.2 to 91.1±9.7. However, there were no significant changes in body mass index, blood pressure, heart rate, or body composition before and after the 8-session sauna therapy.

Conclusion

Dry sauna improved the health-related quality of life of obese patients without adverse events. Further clinical studies in larger study populations are needed to verify these findings and provide concrete evidence for obesity treatment.

Patients' perspective of the effectiveness and acceptability of pharmacological and non-pharmacological treatments of fibromyalgia

Background and aims Fibromyalgia is a complex condition characterised by widespread pain, sleep disturbance, fatigue and cognitive impairment, with a global mean prevalence estimated at 2.7%. There are inconsistencies in guidelines on the treatment of fibromyalgia leading to dissatisfaction from patients and healthcare professionals. This study investigated patient-reported outcomes of pharmacological and non-pharmacological treatment usage and effectiveness with an assessment of acceptability. Methods Nine hundred and forty-one participants completed a self-administered anonymous questionnaire giving quantitative data of demographics, treatment usage and treatment outcomes. Participant-reported effectiveness and side effects were compared in the following treatment classes: analgesics, antidepressants, gabapentinoids, gastrointestinal treatments, activity interventions, dietary-based treatments, and psychological, physical and alternative therapies. Participants also reported whether they knew about or had tried different treatments. Results The results from the online survey indicated that the range of mean effectiveness ratings were similar for pharmacological and non-pharmacological treatments, whereas non-pharmacological treatments had lower side effects ratings and higher acceptability relative to pharmacological treatments. Participants were not aware of some treatment options. Conclusions The results show lower side effects ratings and higher acceptability for non-pharmacological treatments compared to pharmacological treatments despite similar effectiveness ratings. Implications This article presents results from a large online survey on fibromyalgia patient perspectives of pharmacological and non-pharmacological treatments. Results will inform healthcare professionals and patients about optimal treatments based on ratings of effectiveness, side effects and acceptability that are tailored to patient symptom profiles. Some participants were unaware of treatment options highlighting the importance of patient education allowing collaboration between patients and healthcare professionals to find optimal treatments.

Effects of alternating exposure to cold and heat for 14 days on cold tolerance in winter

People are exposed to heat regularly due to their jobs or daily habits in cold winter, but few studies have reported whether parallel heat and cold exposure and diminish cold acclimation. This study was conducted to investigate the effects of alternating exposure to cold and heat on cold tolerance in eight young males. A daily acclimation program to cold and heat, which consisted of 2-h sitting at 10 °C air in the morning and 2-h running and rest at 30 °C air in the afternoon, was conducted for 14 consecutive days. Eight male subjects participated in a cold tolerance test (10 °C [ ± 0.3], 40%RH[ ± 3]) before (PRE) and after (POST) completing the alternating exposure program. During the cold tolerance test, subjects remained sitting upright on a chair for 60 min. Rectal temperature (T_re) was lower in POST than in PRE during the 60-min cold tolerance test (P = 0.027). During the cold tolerance test, systolic, diastolic, and mean arterial blood pressures in POST were lower than those in PRE (P = 0.006, P = 0.005, and P = 0.004). No significant differences in skin temperatures between PRE and POST were found for the cold tolerance test. There were no significant differences in energy expenditure during cold exposure between PRE and POST. Subjects felt less cold in POST than in PRE (P = 0.013) whereas there was no significant difference in overall thermal comfort between PRE and POST. These results suggest that cold adaptation can still occur in the presence of heat stress.

Effects of thermal therapy combining sauna therapy and underwater exercise in patients with fibromyalgia

Fibromyalgia syndrome (FMS) is a chronic disorder that is characterized by widespread pain with localized tenderness. We aimed to investigate whether thermal therapy combining sauna therapy and underwater exercise improved pain, symptoms, and quality of life (QOL) in FMS patients. Forty-four female FMS patients who fulfilled the American College of Rheumatology (ACR) criteria received 12-week thermal therapy program comprising sauna therapy once daily for 3 days/week and underwater exercise once daily for 2 days/week. Pain, symptoms, and QOL were assessed using a pain visual analog scale (VAS), a fibromyalgia impact questionnaire (FIQ), and a short form 36-item questionnaire (SF-36), respectively. All of the patients reported significant reductions in pain and symptoms of 31-77% after the 12-week thermal therapy program, which remained relatively stable (28-68%) during the 6-month follow-up period (that is, the thermal therapy program improved both the short-term and the long-term VAS and FIQ scores). Improvements were also observed in the SF-36 score. Thermal therapy combining sauna therapy and underwater exercise improved the QOL as well as the pain and symptoms of FMS patients.

Acclimatisation of Scottish Blackface sheep to cold. 1. Rectal temperature responses

Closely shorn Scottish Blackface female sheep aged 9–14 months, half on high plane and half on low plane nutrition, were subjected, in climate chambers, to two short acute cold exposures down to – 20° C. The exposures were separated by a period of two weeks in either a thermoneutral environment ( + 30° C.) or a subcritical environment ( + 8° C.). Thirty-seven out of 40 sheep showed a greater resistance to body cooling at the second exposure. The mean rates of fall of rectal temperature (in° C. per 100 min. exposure) were 0·42 at the first exposure and 0·22 at the second exposure. One group of sheep showed virtually complete resistance to cooling at second exposure under the specific test conditions used. The highly significant increase in cooling resistance was taken as a measure of acclimatisation.

The main conclusions were as follows:

1. Blackface sheep could acclimatise to cold as a result of one acute exposure to cold lasting about 8 hours.

2. Acclimatisation was slightly greater amongst sheep kept at a subcritical temperature (+8° C.) between acute exposures.

3. Additional data suggested that some acclimatisation resulted from 2 weeks prior exposure to +8° C. alone; but none was induced by 2 weeks prior habituation to the climate chamber environment at + 30° C.

4. Sheep on high plane nutrition showed greater initial cold resistance and slightly greater ability to acclimatise than those on low plane nutrition.

5. Cold resistance was more closely related to recent weight gain than to absolute body weight.

6. There was great individual variation in initial cold resistance and in ability to acclimatise.

7. Sheep kept at + 8° C. between acute cold exposures maintained significantly lower rectal temperatures than those kept at +30° C.

Acclimatization of Scottish Blackface sheep to cold. 2. Skin temperature, heart rate, respiration rate, shivering intensity and skinfold thickness

Closely shorn Scottish Blackface female sheep aged 9–14 months, half on high plane and half on low plane nutrition, were subjected, in climate chambers, to two short acute cold exposures down to −20°C. The acute exposures were separated by two weeks chronic exposure to a moderately subcriticai temperature (+8°C) or to a thermoneutral temperature (+30°C). Most of the sheep showed a greater resistance to body cooling at the second acute exposure (Slee and Sykes, 1967). This increased resistance to hypothermia, defined as acclimatization, was apparently influenced more by acute than by chronic cold exposure. The present paper deals with changes in skin temperature, heart rate, shivering intensity and skinfold thickness which also resulted from cold exposure, and accompanied acclimatization.

After acute cold exposure followed by chronic exposure to +8°C the following changes in these parameters were observed:

1. Extremity skin temperatures and heart rates were consistently increased at thermoneutral ambient temperatures.

2. Vasoconstriction of the extremities and increased heart rate, both of which normally occur during the early stages of cold exposure, were delayed.

3. Heart rates at sub-zero ambient temperatures were increased.

4. Cold-induced vasodilatation at sub-zero ambient temperatures was increased.

After acute cold treatment alone the intensity of shivering during the second acute exposure was reduced. Also the onset of foot vasoconstriction was slightly delayed.

A highly significant relationship was observed between shivering intensity and heart rate during cold exposure.

Plane of nutrition had less effect on the physiological responses to cooling than did previous cold experience.

It was suggested in discussion that the physiological responses associated with acclimatization were: elevated basal metabolic rate, delayed onset of vasoconstriction and delayed metabolic response to cold, and consequent lowering of the critical temperature. Summit metabolism was also increased and shivering intensity reduced during acute cold exposure. Some of these responses could have resulted from either acute or chronic moderate cold exposure. However their persistence, once induced, appeared to depend upon continued exposure to moderate cold.

Efficacy of Waon therapy for fibromyalgia

OBJECTIVE

Fibromyalgia syndrome (FMS) is a chronic syndrome characterized by widespread pain with tenderness in specific areas. We examined the applicability of Waon therapy (soothing warmth therapy) as a new method of pain treatment in patients with FMS.

METHODS

Thirteen female FMS patients (mean age, 45.2+/-15.5 years old; range, 25-75) who fulfilled the criteria of the American College of Rheumatology participated in this study. Patients received Waon therapy once per day for 2 or 5 days/week. The patients were placed in the supine or sitting position in a far infrared-ray dry sauna maintained at an even temperature of 60 degrees C for 15 minutes, and then transferred to a room maintained at 26-27 degrees C where they were covered with a blanket from the neck down to keep them warm for 30 minutes. Reductions in subjective pain and symptoms were determined using the pain visual analog scale (VAS) and fibromyalgia impact questionnaire (FIQ).

RESULTS

All patients experienced a significant reduction in pain by about half after the first session of Waon therapy (11-70%), and the effect of Waon therapy became stable (20-78%) after 10 treatments. Pain VAS and FIQ symptom scores were significantly (p<0.01) decreased after Waon therapy and remained low throughout the observation period.

CONCLUSION

Waon therapy is effective for the treatment of fibromyalgia syndrome.

Repeated thermal therapy diminishes appetite loss and subjective complaints in mildly depressed patients

OBJECTIVE

We observed that repeated thermal therapy improved appetite loss and general well-being in patients with chronic heart failure. The purpose of this study is to clarify the effects of repeated thermal therapy in mildly depressed patients with appetite loss and subjective complaints.

METHODS

Twenty-eight mildly depressed inpatients with general fatigue, appetite loss, and somatic and mental complaints were randomly assigned to thermal therapy group (n = 14) or nonthermal therapy group (n = 14). Patients in the thermal therapy group were treated with 60 degrees C far-infrared ray dry sauna for 15 minutes and were then kept at bed rest with a blanket for 30 minutes once a day, 5 days a week for a total of 20 sessions in 4 weeks.

RESULTS

Four weeks after admission, somatic complaints, hunger, and relaxation scores significantly improved (p < .001, p < .0001, p < .0001, respectively) and mental complaints slightly improved (p = .054) in the thermal therapy group compared with the nonthermal therapy group. Furthermore, the plasma ghrelin concentrations and daily caloric intake in the thermal therapy group significantly increased compared with the nonthermal therapy group (p < .05).

CONCLUSIONS

These findings suggest that repeated thermal therapy may be useful for mildly depressed patients with appetite loss and subjective complaints.

The effects of repeated thermal therapy for two patients with chronic fatigue syndrome

OBJECTIVE

This paper describes the successful treatment of two patients with chronic fatigue syndrome (CFS) using repeated thermal therapy.

METHODS

Two patients with CFS underwent treatment with prednisolone (PSL), with no satisfactory effect. They were subjected to thermal therapy that consisted of a far-infrared ray dry sauna at 60 degrees C and postsauna warming. The therapy was performed once a day, for a total of 35 sessions. After discharge, these subjects continued the therapy once or twice a week on an outpatient basis for 1 year.

RESULTS

Symptoms such as fatigue, pain, sleep disturbance, and low-grade fever were dramatically improved after 15 to 25 sessions of thermal therapy. Although PSL administration was discontinued, the subjects showed no relapse or exacerbation of symptoms during the first year after discharge. The patients became socially rehabilitated 6 months after discharge.

CONCLUSIONS

These results suggest that repeated thermal therapy might be a promising method for the treatment of CFS.

Adaptation to exercise in the cold

The winter athlete has several potential tactics for sustaining body temperature in the face of severe cold. An increase in the intensity of physical activity may be counter-productive because of increased respiratory heat loss, increased air or water movement over the body surface, and a pumping of air or water beneath the clothing. Shivering can generate heat at a rate of 10 to 15 kJ/min, but it impairs skilled performance, while the resultant glycogen usage hastens the onset of fatigue and mental confusion. Non-shivering thermogenesis could arise in either brown adipose tissue or white fat. Brown adipose tissue generates heat by the action of free fatty acids in uncoupling mitochondrial electron transport, and by noradrenaline-induced membrane depolarisation and sodium pumping. The existence of brown adipose tissue in human adults is controversial, and although there are theoretical mechanisms of heat production in white fat, their contribution to the maintenance of body temperature is small. Acclimatisation to cold develops over the course of about 10 days, and in humans the primary change is an insulative, hypothermic type of response; this reflects the intermittent nature of most occupational and athletic exposures to cold. Nevertheless, with more sustained exposure to cold air or water, humans can apparently develop the humoral type of acclimatisation described in small mammals, with an increased output of noradrenaline and/or thyroxine. The associated mobilisation of free fatty acids suggests the possibility of using winter sport as a pleasant method of treating obesity. In men, a combination of moderate exercise and facial cooling induces a substantial fat loss over a 1- to 2-week period, with an associated ketonuria, proteinuria, and increase of body mass. Possible factors contributing to this fat loss include: (a) a small energy deficit; (b) the energy cost of synthesising new lean tissue; (c) energy loss through the storage and excretion of ketone bodies; (d) catecholamine-induced 'futile' metabolic cycles with increased resting metabolism; and (e) a specific reaction to cold dehydration. Current limitations for the clinical application of such treatment include uncertainty regarding optimal environmental conditions, concern over possible pathological reactions to cold, and suggestions of a less satisfactory fat mobilisation in female patients. Possible interactions between physical fitness and metabolic reactions to cold remain controversial.(ABSTRACT TRUNCATED AT 400 WORDS)

Improved response to heat after moderate physical training in man

7 young men marched for 6 days (35 km daily) in a cool climate at about 35% of their VO2max. Sweat output was measured at rest in a climatic chamber during a controlled hyperthemia test performed before and after the trial. 4 subjects served as controls. The main finding of the study was that sweat output increased 17.3% +/- 1.5 SEM on the post-trial test, without any change in VO2max. It is concluded that moderate physical training can improve heat responses in resting man.