Hyperthermia
42 degrees C whole body hyperthermia, as an adjunct to chemotherapy induces prolonged T cell activation in patients with various malignant diseases. 42 degree Celsius = 107.6 degree Fahrenheit

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12439605&query_hl=7

Cancer Immunol Immunother. 2002 Dec;51(11-12):603-13. Epub 2002 Oct 18

Atanackovic D, Nierhaus A, Neumeier M, Hossfeld DK, Hegewisch-Becker S.

Department of Oncology and Hematology, University Clinic Eppendorf, Hamburg, Germany. atanackd@mskcc.org

Whole body hyperthermia (WBH) has been used as an adjunct to radio-/chemotherapy in patients with various malignant diseases. Although clear evidence is still missing, it has been hypothesized that an activation of the immune system might contribute to the therapeutic effect of WBH. To examine whether a treatment with 60-minute 41.8 degrees C WBH as an adjunct to chemotherapy (WBH-CT) induces an activation of T cells, blood samples were collected at numerous time points before and up to 48 h post-treatment. The aim of this study was to examine the effect of WBH-CT on the expression of a broad range of activation markers on peripheral blood lymphocytes (PBL), on serum cytokines and intracellular cytokine levels in T cells, and the capacity of these cells to proliferate. Immediately after 41.8 degrees C WBH-CT treatment, a drastic increase in peripheral natural killer (NK) cells ( P<0.05) and CD56+ cytotoxic T lymphocytes (CTL; P<0.01) in the patients' peripheral blood was observed. At 5 h post-treatment, the percentages of both effector cell types had returned to baseline levels. This transient phenomenon was accompanied by a short period of reduced T cell activity, indicated by diminished serum levels of soluble interleukin-2 receptors (sIL-2R) at 3 h post-WBH-CT ( P<0.05) and decreased lymphocytic proliferation at the same point in time. This first phase was followed by a marked but short-lived increase in the patients' serum levels of interleukin-6 (IL-6; P<0.01) during the first 5 h following treatment, with a subsequent decrease to baseline levels at 24 h and significantly increased serum levels of tumor necrosis factor-alpha (TNF-alpha) at 0 h ( P<0.01), 3 h ( P<0.05), 5 h ( P<0.05) and 24 h ( P<0.01) post-WBH-CT. The third phase of the immunological consequences of WBH-CT consisted of an increase in the percentage of peripheral cytotoxic T lymphocytes (CTL) expressing CD56, reaching a maximum at 48 h post-WBH ( P<0.01). Furthermore, the percentage of CD4+ T cells expressing the T cell activation marker CD69 increased nearly two-fold over time, reaching its maximum at 48 h ( P<0.05). As an additional marker for T cell activation, serum levels of sIL-2R increased markedly ( P<0.01), reaching maximum levels at the same point in time. Elevated intracellular concentrations of interferon-gamma (IFN-gamma) and/or TNF-alpha in CD8+ T cells were found in 4 out of 5 patients at 24 h post-WBH-CT. Since similar changes were not observed in patients receiving chemotherapy alone, this is the first study to provide evidence for prolonged WBH-CT-induced activation of human T cells.

 

Hyperthermia in humans enhances interferon-gamma synthesis and alters the peripheral lymphocyte population.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3132509&query_hl=7



Downing JF, Martinez-Valdez H, Elizondo RS, Walker EB, Taylor MW.

Department of Biology, Indiana University, Bloomington 47405.

Induction of hyperthermia (39 degrees C) in human volunteers by immersion in warm water (41-45 degrees C) rapidly alters the cell populations in the peripheral blood. In addition to granulocytosis, there is an alteration of the normal ratios among T-lymphocyte subsets. Following in vitro mitogen stimulation, lymphocytes from hyperthermic individuals produce as much as 10-fold more interferon-gamma (IFN-gamma) than cells withdrawn at basal core temperatures from the same individuals. A temperature threshold of 39 degrees C for this response suggests potential relevance to fever. No change was noted in the activity of the macrophage population. The possible involvement of interleukin-2 (IL-2) in this enhanced production is discussed. No changes were noted in the circulating levels of IFN-gamma

 

Effects of whole body hyperthermia 41 degrees C on the frequency of tumor cells  Clin Cancer Res. 2003 Jun;9(6):2079-84.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12796371&query_hl=6

Hegewisch-Becker S, Braun K, Otte M, Corovic A, Atanackovic D, Nierhaus A, Hossfeld DK, Pantel K.

Department of Oncology/Hematology, University Hospital Hamburg-Eppendorf, Hamburg D-20246, Germany. hegewisc@uke.uni-hamburg.de

PURPOSE: Combining heat with antineoplastic drugs has produced evidence of antitumor synergism. An increasing number of trials are investigating whole body hyperthermia (WBH) in combination with chemotherapy in patients with advanced malignancies. Here we investigated whether the hyperdynamic state of the circulation as a consequence of WBH may stimulate dissemination of malignant cells. EXPERIMENTAL DESIGN: WBH in combination with chemotherapy was administered by a radiant heat device to 20 consecutive patients with advanced epithelial malignancies. One WBH session lasted for approximately 4 h (90 min heating time, 60 min plateau at 41.8 degrees C, and 60-80 min cooling). Peripheral blood was drawn before WBH treatment (baseline), at the end of the plateau (1 h), and 24 h and 48 h thereafter. After removal of leukocytes using anti-CD45 magnetic beads, circulating tumor cells were detected immunocytochemically using the monoclonal antibody A45-B/B3, which binds to a common epitope present on various cytokeratins. RESULTS: The method used to detect tumor cells in the peripheral blood proved to be specific and very sensitive (detection limit 1 tumor cell per 1.7 x 10(5) peripheral blood mononuclear cell). Before WBH, 6 of 20 patients had cyto-keratin-positive cells in their blood. A treatment-induced increase in the number of circulating tumor cells became statistically significant at 24 h after WBH (P = 0.043) and was detected in a total of 9 patients, 5 of whom had no detectable malignant cells at baseline. There was no evidence of a correlation between an increase in the number of circulating tumor cells and increased metastasis frequency. CONCLUSIONS: Our findings suggest that WBH might induce a temporary release of tumor cells into the circulation, but this spread appears to be clinically not significant in patients with advanced malignancies.

 

Influence of elevated temperature on natural killer cell activity, lymphokine-activated killer cell activity and lectin-dependent cytotoxicity of human umbilical cord blood and adult blood cells 40 degree Celsius = 104 degree Fahrenheit

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8040029&query_hl=7

Int J Radiat Oncol Biol Phys. 1994 Jul 1;29(4):821-6.

Shen RN, Lu L, Young P, Shidnia H, Hornback NB, Broxmeyer HE.

Department of Medicine (Hematology-Oncology), Indiana University School of Medicine, Walther Oncology Center, Indianapolis 46202-5121.

PURPOSE: To determine whether hyperthermia is to the benefit or detriment of host immune function, the effect of hyperthermia was evaluated on various functions of T-lymphocytes from human umbilical cord blood and compared to that of adult blood. METHODS AND MATERIALS: Nonadherent mononuclear cells from cord blood or adult blood were used as the effector cells. To generate lymphokine activated killer (LAK) cells, effector cells were kept in culture for 5 days in complete medium containing recombinant human interleukin-2. To activate effector cells to become cytotoxic, cells were kept in culture in complete medium containing Con A. Cytotoxicity was determined in a standard 4-h chromium release assay using K-562 human erythroleukemic cells (in the natural killer cell activity assay) or Daudi cells (in the LAK cell activity or Lectin dependent cytotoxicity assay) as targets. For heat effects, cells in complete medium were heated at the desired temperature in a water bath for 1 h. RESULTS: Lymphokine-activated killer cell activity, lectin-dependent cytotoxicity and T-cell proliferative capacity were not deficient in human cord blood. Cytotoxic activities of T-cells from adult blood as well as from cord blood can be enhanced at febrile range (< or = 40 degrees C), and were significantly decreased by exposure to 1 h at 42 degrees C. CONCLUSION: The febrile responses (< or = 40 degrees C) to infection, in the course of malignant disease and with biological response modifiers treatment, may all be related to host defense mechanisms. Based on these observations, whole body hyperthermia (< or = 40 degrees C), in combination with the appropriate cytokines, may have therapeutic potential in the treatment of neonatal infections and malignancies under certain circumstances. Hyperthermia in febrile range may, therefore, confer an important immunoregulatory advantage to the host. In contrast, tumor killing therapeutic temperature (> 42 degrees C) which inhibits host immunocompetence should probably be used only for local hyperthermia.

 

Evaluation of steam therapy in acute lower respiratory tract infections: a pilot study

Indian Pediatr. 1990 Sep;27(9):945-51.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2286438&dopt=Citation

Singh M, Singhi S, Walia BN.

Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh.

In a prospective controlled evaluation of steam therapy, in severe acute lower respiratory tract infection (ALRI) requiring hospitalization, 16 cases of bronchiolitis and 20 cases of pneumonia were assigned alternately to receive steam therapy in a cloth tent (Study Group); others served as controls. Respiratory status was assessed at the time of admission and subsequently at 6 hourly interval for 48 hours. No advantage of steam therapy could be identified in children with pneumonia. Bronchiolitis patients on steam therapy, as compared to the controls, showed a significant decrease in respiratory distress within first 24 hours after hospitalization and took significantly shorter time for recovery from the distress. The study patients also showed a tendency for rapid improvement in hypoxemia. Further critically controlled studies with a larger sample size are warranted.

Effects of artificially induced fever on serum proteins, vitamin levels and hematological values in human subjects

http://jap.physiology.org/cgi/content/abstract/14/5/768

J Appl Physiol 14: 768-770, 1959;
8750-7587/59 $5.00

José Méndez 1, Nevin S. Scrimshaw 1, Carlos Salvadó 1, and Manuel López Selva 1

1 Institute of Nutrition of Central America and Panama (INCAP), and the Neuropsychiatric Hospital, Guatemala City, Guatemala

Ten male subjects in apparently good health were submitted to artificial hyperpyrexia of 2°–3°C above their initial orally determined body temperature for 2-hour periods. The pulse rate was markedly increased and the diastolic blood pressure was markedly decreased. Other major changes observed were a highly significant decrease of serum vitamin A levels and a highly significant increase of the white cell count, due primarily to an increase of the neutrophils. An eosinopenic effect observed was believed to be related to the stress of fever treatment. Minor changes were observed in the red cell count and in the serum gamma globulin fraction, which showed a delayed decrease. No changes were observed in carotene, vitamin E, alkaline phosphatase, riboflavin, or ascorbic acid.

The effect of in vivo hyperthermia on selected lymphokines in man

Lymphokine Res. 1987 Spring;6(2):103-9.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3495705&query_hl=5

Downing JF, Taylor MW.

We have previously demonstrated that artificially induced hyperthermia in man enhances the subsequent production of interferon gamma (IFN-gamma) in isolated leukocyte cultures. The mechanism(s) responsible for this response may involve changes in the circulating lymphocyte populations and may also reflect activation processes occurring in vivo due to hormonal influences. In order to determine whether hyperthermia was associated with other immunostimulatory effects, we measured lymphocyte activation, natural killer cell activity, interleukin-2 (IL-2) production and endotoxin-induced tumor necrosis factor (TNF) activity in blood samples obtained from normothermic (37 degrees C) and hyperthermic (39 degrees C) individuals. Lymphocyte transformation was significantly depressed in post-hyperthermic cultures compared to pre-hyperthermic control cultures. Pre-hyperthermic autologous human plasma was less effective than fetal calf serum in promoting DNA synthesis, while post-hyperthermic plasma suppressed mitogen-induced activation. Natural killer (NK) cell activity was increased by the elevation of core body temperature. Interleukin-2 (IL-2) production in phytohemagglutinin-stimulated mononuclear cell cultures was also elevated when cells were isolated from hyperthermic individuals relative to a paired normothermic control sample. Lipopolysaccharide-induced tumor necrosis factor (TNF) synthesis in monocyte cultures was unchanged by elevation of the core body temperature. This study indicates that in vivo hyperthermia can produce an immunostimulatory effect, an immunosuppressive effect, or no effect on different parameters of the immune system.

Sex differences in endocrine response to hyperthermia in sauna.

Acta Physiol Scand. 1994 Mar;150(3):293-8.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8010136&query_hl=2



Jezova D, Kvetnansky R, Vigas M.

Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava.

Neuroendocrine response was investigated during and after a single 20 min bath in sauna (80 degrees C) in a group of 8 healthy men and 8 healthy women. In an additional group of 8 young men, the dynamics of plasma ACTH and cortisol levels were studied during a 30 min sauna exposure (90 degrees C). This dynamic study showed a biphasic response of plasma cortisol which decreased during the initial phase of sauna bath (15 min) and increased thereafter, reaching its maximum 15 min after the end of bathing. Maximal increase in plasma ACTH levels occurred 15 min earlier. In the first sauna exposed group the increase in body temperature was the same (about 2 degrees C) in both sexes. Nevertheless, the elevation in plasma ACTH concentration was significantly more pronounced in women than in men. In the plasma collected at the end of sauna bath inside the sauna room, a significant rise in both adrenaline and noradrenaline levels was found. Though the catecholamine responses were similar in both groups, the increase in heart rate during sauna bath was significantly higher in women. Sauna-induced prolactin release was also more pronounced in women compared with men. Thus hyperthermia induced by sauna exposure resulted in a more pronounced neuroendocrine activation in women compared with men. Moreover, it is evident that repeated blood sampling is necessary to reveal the sauna-induced activation of some hormonal systems

Heat Halts Pain Inside The Body

Main Category: Pain / Anesthetics News
Article Date: 06 Jul 2006 - 0:00am (PDT)

 

The old wives' tale that heat relieves abdominal pain, such as colic or menstrual pain, has been scientifically proven by a UCL (University College London) scientist, who will presented the findings at the Physiological Society's annual conference hosted by UCL.

Dr Brian King, of the UCL Department of Physiology, led the research that found the molecular basis for the long-standing theory that heat, such as that from a hot-water bottle applied to the skin, provides relief from internal pains, such as stomach aches, for up to an hour.

Dr King said: "The pain of colic, cystitis and period pain is caused by a temporary reduction in blood flow to or over-distension of hollow organs such as the bowel or uterus, causing local tissue damage and activating pain receptors.

"The heat doesn't just provide comfort and have a placebo effect - it actually deactivates the pain at a molecular level in much the same way as pharmaceutical painkillers work. We have discovered how this molecular process works."

If heat over 40 degrees Celsius is applied to the skin near to where internal pain is felt, it switches on heat receptors located at the site of injury. These heat receptors in turn block the effect of chemical messengers that cause pain to be detected by the body.

The team found that the heat receptor, known as TRPV1, can block P2X3 pain receptors. These pain receptors are activated by ATP, the body's source of energy, when it is released from damaged and dying cells. By blocking the pain receptors, TRPV1 is able to stop the pain being sensed by the body.

Dr King added: "The problem with heat is that it can only provide temporary relief. The focus of future research will continue to be the discovery and development of pain relief drugs that will block P2X3 pain receptors. Our research adds to a body of work showing that P2X3 receptors are key to the development of drugs that will alleviate debilitating internal pain."

Scientists made this discovery using recombinant DNA technology to make both heat and pain receptor proteins in the same host cell and watching the molecular interactions between the TRPV1 protein and the P2X3 protein, switched on by capsaicin, the active ingredient in chilli, and ATP, respectively.

###

Contact: Alex Brew
University College London

Analysis of body water compartments after a short sauna bath using bioelectric impedance analysis

Acta Diabetol. 2003 Oct;40 Suppl 1:S207-9.

Servidio MF, Mohamed EI, Maiolo C, Hereba AT, Perrone F, Garofano P, Iacopino L.

Divisions of Human Nutrition and Clinical Pathology, Faculty of Medicine and Surgery, University of Tor Vergata, Rome, Italy.

Studies have suggested that long-term sauna bathing may lower blood pressure in persons with hypertension by causing a direct loss of extracellular water and plasma minerals. The objective of the present study was to evaluate the effect of short-term sauna bathing on body water compartments as estimated by bioelectric impedance analysis (BIA). We recruited 15 men [mean age (+/-SD) of 23.93+/-5.12 years and mean body mass index (BMI) of 23.25+/-2.84 kg/m(2)] and 10 women matched for age and BMI. Total body resistance, reactance, and impedance were measured for all participants using BIA, at baseline, after a short sauna bath, and after a rest period. Total, extracellular, and intracellular water compartments were calculated using BIA formulae. There were no significant differences for any of the body water compartments when comparing the measurements taken before and after the sauna bath and after the rest period. However, it remains to be determined whether or not BIA is sensitive to rapid changes in water volume

 

Circulatory changes in acute sauna hyperthermia after heart transplantation

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8256470&query_hl=2

Z Gesamte Inn Med. 1993 Oct;48(10):502-5.

[Article in German]

Winterfeld HJ, Siewert H, Engelmann U, Aurisch R, Frenzel R, Bohm J, Strangfeld D, Warnke H.

Poliklinik fur Physiotherapie, Medizinischen Fakultat (Charite) der Humboldt-Universitat zu Berlin.

The authors report on the influence of a single sauna-stay of patients following heart transplantation (HTX) during the rehabilitation phase III. Investigations of blood pressure, heart rate, changer in hemodynamics in the small and large vessels in 8 male patients following HTX (medium age: 42 years) showed that sauna-hyperthermia is well tolerated. We watched significant decreases of blood pressure (systolic and diastolic values), an improvement of the microcirculation in the small vessels, an increase of the left ventricular ejection fraction (LVEF) and a decrease of the total peripheric vascular resistance (TPVR). Possibilities and limitations of sauna-therapy for the therapy of risk factors following HTX especially under immunosuppression are discussed. First results are demonstrated.

Controlled localized heat therapy in cutaneous warts

P. Stern and N. Levine
Section of Dermatology, University of Arizona Health Sciences Center, Tucson 85724.

BACKGROUND--Controlled localized heating as a method of superficial tissue destruction has been used in veterinary medicine for the treatment of benign and malignant tumors. The rationale for its use is that the diseased tissue being treated is more sensitive to the effects of heating than is normal tissue. This technology was applied to the treatment of common hand warts in a placebo-controlled study. OBSERVATIONS--Twenty-nine warts were treated one to four times (median, two times) at 50 degrees C for 30 to 60 seconds. Twenty-five (86%) of 29 treated verrucae regressed completely while seven (41%) of 17 control warts resolved during the course of the study. No wart that regressed regrew during the follow-up period (mean, 15.6 weeks). CONCLUSIONS--Controlled localized heating can cause the regression of hand warts. The 86% regression rate compares favorably with other wart treatment modalities. The mechanism of action and the effect of heat on these virally induced tumors is not known but may involve direct antiviral effects, physical destruction of the tumor, or the promotion of an inflammatory response that ultimately eradicates the lesion.

Vol. 128 No. 7, July 1992

http://archderm.ama-assn.org/cgi/content/abstract/128/7/945

Effects of sauna on sperm movement characteristics of normal men measured by computer-assisted sperm analysis.

Saikhun J, Kitiyanant Y, Vanadurongwan V, Pavasuthipaisit K.

Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, Thailand.

The effects of sauna exposure on sperm movement characteristics and other semen parameters were evaluated using computer-assisted sperm analysis (CASA). A significant (p < 0.01) decrease in average path velocity (VAP), curvilinear velocity (VCL) and amplitude of lateral head displacement (ALH) was found after exposure to sauna for 2 weeks. The altered parameters returned to their original values within 1 week after cessation of sauna exposure. Mean values for semen volume, sperm count, percentage motility, sperm morphology and sperm penetration assay (SPA) were not statistically different during and after sauna, when compared to the corresponding control values. The results suggest that increasing scrotal temperature by sauna causes a reversible decrease in sperm movement parameters.
Exposure to high ambient temperature increases absorption and plasma concentrations of transdermal nicotine.

Vanakoski J, Seppala T, Sievi E, Lunell E.

Department of Pharmacology and Toxicology, University of Helsinki, Finland.

Absorption and plasma concentrations of transdermally delivered drugs may be increased during heat exposure. We studied the effects of short-term heat exposure in a sauna bath on the pharmacokinetics of transdermal nicotine, 25 mg/16 hr, in 12 healthy smokers in an open, randomized crossover study that consisted of a control session and a sauna bathing session. In the sauna session the subjects stayed seated in a sauna bath (mean temperature 82 degrees C (180 degrees F); mean relative humidity 28%) for three 10-minute periods separated by two 5-minute breaks. Sauna bathing significantly (p < 0.01 versus control) increased peak plasma concentration, area under the plasma concentration-time curve from 0 to 1 hour, the amount of nicotine absorbed, and the mean plasma nicotine concentrations during heat exposure. No significant difference in nicotine area under the plasma concentration-time curve from 0 to 3 hours was observed. In addition, the combined effects of transdermal nicotine and sauna bathing on hemodynamics, some psychomotor skills, and subjective symptoms were evaluated. We concluded that absorption and plasma concentrations of transdermally delivered nicotine may be increased during exposure to high ambient temperature, probably because of enhanced skin blood flow. However, no adverse symptoms were recorded.
How the sauna affects the endocrine system

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3218898&query_hl=26

Ann Clin Res. 1988;20(4):262-6.

Kukkonen-Harjula K, Kauppinen K.

UKK-Institute for Health Promotion Research, Tampere, Finland.

The sauna induces changes in the secretion of hormones, some similar to changes induced in any other stress situation and others characteristic of exposure to the sauna. Noradrenaline is usually the only catecholamine raised by the sauna in people accustomed to it. The secretion of the antidiuretic hormone is increased and the renin-angiotensin-aldosterone system is activated. The concentrations of the growth hormone and prolactin, in particular, secreted from the anterior pituitary are increased in the circulation. The concentration of the immunoreactive beta-endorphin in blood may also increase which may reflect the feeling of pleasure or, on the other hand, discomfort induced by the sauna. The views on the effects of the sauna on the secretion of the ACTH and cortisol are partly contradictory, probably due to differing ways of taking the sauna bath. In Finnish sauna takers the concentration of cortisol in blood is not usually increased. The changes induced by the sauna in various hormone concentrations in the circulation are, however, normalized within a couple of hours after the heat stress.

Wien Klin Wochenschr. 2002 Feb 15;114(3):102-7.
Comment in:
Human monocyte stimulation by experimental whole body hyperthermia.

Zellner M, Hergovics N, Roth E, Jilma B, Spittler A, Oehler R.

Surgical Research Laboratories, University of Vienna, Austria. mariazellner@akh-wien.ac.at

The thermal effect of fever, an evolutionarily conserved acute-phase response, has been associated with better survival and a shorter duration of disease in cases of infection. The molecular consequence of this beneficial fever response is poorly understood. To determine the influence of hyperthermia on human monocytes, which are important for the recognition and elimination of pathogens, twelve healthy volunteers were immersed in a 39.5 degrees C hot water bath to increase their body temperature. The expression of the endotoxin receptor CD14 and the complement receptor CD11b increased after the hot water bath (P < 0.05), whereas the expression of the selectin CD62L, which mediates the initial attachment of leukocytes at the endothelium during inflammation, was downregulated after hyperthermia (P < 0.05). Comparable changes in monocyte receptor expression were observed after in vitro hyperthermia. Furthermore, 3 hours after in vivo hyperthermia, the response of monocytes to endotoxin was enhanced in an ex vivo lipopolysaccharide stimulation assay, as expressed by a greater TNF-alpha release (P < 0.05). We conclude that the thermal effect of fever directly activates monocytes, which increases their ability to respond to bacterial challenge.
Physical effects of negative air ions in a wet sauna.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9140213&query_hl=2

Int J Biometeorol. 1997 Apr;40(2):107-12.

Watanabe I, Noro H, Ohtsuka Y, Mano Y, Agishi Y.

Department of Rehabilitation and Physical Medicine, Hokkaido University School of Medicine, Sapporo City, Japan.

The physical effects of negative air ions on humans were determined in an experimental sauna room equipped with an ionizer. Thirteen healthy persons took a wet sauna bath (dry bulb temperature 42 degrees C, relative humidity 100%, 10 min exposure) with or without negative air ions. The subjects were not told when they were being exposed to negative air ions. There were no differences in the moods of these persons or changes in their blood pressures between the two saunas. The surface temperatures of the foreheads, hands, and legs in the sauna with negative ions were significantly higher than those in the sauna without ions. The pulse rates and sweat produced in the sauna with ions were significantly higher than those in the sauna without ions. The results suggest that negative ions may amplify the effects on humans of the sauna.

Regular sauna bathing and the incidence of common cold

Ann Med. 1990;22(4):225-7.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2248758&query_hl=2

Ernst E, Pecho E, Wirz P, Saradeth T.

Department of Physical Medicine and Rehabilitation, University of Vienna, Austria.

The high morbidity of common colds means that their economic importance is considerable, with colds causing more loss of productivity than any other infection. As no effective prophylaxis is available, this trial was to test the hypothesis that sauna bathing can reduce the incidence of common colds. Twenty-five volunteers were submitted to sauna bathing, with 25 controls abstaining from this or comparable procedures. In both groups the frequency, duration and severity of common colds were recorded for six months. There were significantly fewer episodes of common cold in the sauna group. This was found particularly during the last three months of the study period when the incidence was roughly halved compared to controls. The mean duration and average severity of common colds did not differ significantly between the groups. It is concluded that regular sauna bathing probably reduces the incidence of common colds, but further studies are needed to prove this.
Repeated thermal therapy improves impaired vascular endothelial function in patients with coronary risk factors.

Imamura M, Biro S, Kihara T, Yoshifuku S, Takasaki K, Otsuji Y, Minagoe S, Toyama Y, Tei C.

First Department of Internal Medicine, Faculty of Medicine, Kagoshima University, Sakuragaoka, Kagoshima, Japan.

OBJECTIVES: We sought to determine whether sauna therapy, a thermal vasodilation therapy, improves endothelial function in patients with coronary risk factors such as hypercholesterolemia, hypertension, diabetes mellitus and smoking. BACKGROUND: Exposure to heat is widely used as a traditional therapy in many different cultures. We have recently found that repeated sauna therapy improves endothelial and cardiac function in patients with chronic heart failure. METHODS: Twenty-five men with at least one coronary risk factor (risk group: 38 +/- 7 years) and 10 healthy men without coronary risk factors (control group: 35 +/- 8 years) were enrolled. Patients in the risk group were treated with a 60 degrees C far infrared-ray dry sauna bath for 15 min and then kept in a bed covered with blankets for 30 min once a day for two weeks. To assess endothelial function, brachial artery diameter was measured at rest, during reactive hyperemia (flow-mediated endothelium-dependent dilation [%FMD]), again at rest and after sublingual nitroglycerin administration (endothelium-independent vasodilation [%NTG]) using high-resolution ultrasound. RESULTS: The %FMD was significantly impaired in the risk group compared with the control group (4.0 +/- 1.7% vs. 8.2 +/- 2.7%, p < 0.0001), while %NTG was similar (18.7 +/- 4.2% vs. 20.4 +/- 5.1%). Two weeks of sauna therapy significantly improved %FMD in the risk group (4.0 +/- 1.7% to 5.8 +/- 1.3%, p < 0.001). In contrast, %NTG did not change after two weeks of sauna therapy (18.7 +/- 4.2% to 18.1 +/- 4.1%). CONCLUSIONS: Repeated sauna treatment improves impaired vascular endothelial function in the setting of coronary risk factors, suggesting a therapeutic role for sauna treatment in patients with risk factors for atherosclerosis.
Sauna habits and related symptoms in Finnish children

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2612514&query_hl=2

Eur J Pediatr. 1989 Dec;149(3):221-2

Markkola L, Mattila KJ, Koivikko MJ.

Department of Paediatrics, University Central Hospital of Tampere, Finland.

Fifteen hundred randomly chosen Finnish children aged 0-15 years were studied by a questionnaire about their sauna habits and possible abnormal symptoms during or immediately after the sauna. A total of 1247 families (83%) answered. Almost all children visited the sauna (98.5%), most of them "with pleasure" (83%). Nearly half of the children were in the sauna as often as 2-3 times a week, and over 90% at least once a week. The children's sauna visits began quite early, in 70% during infancy. The time spent in a hot steam bath increased with age. Symptoms were rare and were not serious. Transient symptoms (dizziness, nausea etc.) were the most common. Of the children, 17% had some chronic or recurring disorder, most commonly atopic dermatitis or middle ear infections. In half of the cases of atopic dermatitis it became worse in the sauna. Sauna is a very common practice in Finland, also among children. It does not seem to cause any significant immediate harm to healthy children.

MMW Fortschr Med. 2001 Nov 15;143(46):14.

[Sauna improves endothelial function. Let patients with heart diseases sweat?]

[Article in German]

Guha M

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Systemic responses in man exposed to different heating and cooling treatment in a sauna

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3174262&query_hl=2

Pavlov J Biol Sci. 1988 Jul-Sep;23(3):89-94.

Sudakov KV, Sinitchkin VV, Khasanov AA.

Institute of Physiology, P.K. Anochin, Moscow, U.S.S.R.

Finnish saunas are popular for alleviating psycho-emotional and physical stress. Regular visits to a sauna may promote three adaptive effects: a simulation of the training generally associated with sports activities, the building up of resistance to the effects of extreme exposures, and the regulation of autonomic functions. However, the effect that the sauna has on the physiological mechanisms of humans--particularly, the effect of contrast-cooling following thermal exposure--is still obscure. An example of contrast-cooling following thermal exposure is that caused by swimming after using a sauna; such contrast-cooling may be a risk factor for people with unstable blood pressure, and gradual cooling-off after using a sauna may be preferable. In this series, various autonomic functions under different heating and cooling treatment in a sauna were studied. The authors have concluded that the mode of exposures to heating and cooling under control of Heart Rate (HR) changes has, to a certain extent, a relaxing effect, and thus can be recommended for alleviating psycho-emotional stress.