Clinical implications of thermal therapy in lifestyle-related diseases

The Influence of Ambient Temperature Changes on the Indicators of Inflammation and Oxidative Damage in Blood after Submaximal Exercise

Physical activity has a positive effect on human health and well-being, but intense exercise can cause adverse changes in the organism, leading to the development of oxidative stress and inflammation. The aim of the study was to determine the effect of short-term cold water immersion (CWI) and a sauna bath as methods of postexercise regeneration on the indicators of inflammation and oxidative damage in the blood of healthy recreational athletes. Forty-five male volunteers divided into two groups: 'winter swimmers' who regularly use winter baths (n = 22, average age 43.2 ± 5.9 years) and 'novices' who had not used winter baths regularly before (n = 23, mean age 25 ± 4.8 years) participated in the study. The research was divided into two experiments, differing in the method of postexercise regeneration used, CWI (Experiment I) and a sauna bath (Experiment II). During Experiment I, the volunteers were subjected to a 30-min aerobic exercise, combined with a 20-min rest at room temperature (RT-REST) or a 20-min rest at room temperature with an initial 3-min 8 °C water bath (CWI-REST). During the Experiment II, the volunteers were subjected to the same aerobic exercise, followed by a RT-REST or a sauna bath (SAUNA-REST). The blood samples were taken before physical exercise (control), immediately after exercise and 20 min after completion of regeneration. The concentrations of selected indicators of inflammation, including interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 8 (IL-8), interleukin 10 (IL-10), transforming growth factor β1 (TGF-β1) and tumor necrosis factor α (TNF-α), as well as the activity of indicators of oxidative damage: α1-antitrypsin (AAT) and lysosomal enzymes, including arylsulfatase A (ASA), acid phosphatase (AcP) and cathepsin D (CTS D), were determined. CWI seems to be a more effective post-exercise regeneration method to reduce the inflammatory response compared to a sauna bath. A single sauna bath is associated with the risk of proteolytic tissue damage, but disturbances of cellular homeostasis are less pronounced in people who regularly use cold water baths than in those who are not adapted to thermal stress.

Effects of Elevated Body Temperature on Selected Physiological Indices and Thermal Stress in Athletes and Non-Athletes

The purpose of this study was to determine the effects of active and passive overheating. A group of athletes (A) and non-athletic men (N) underwent an exercise stress test at elevated ambient temperature and sauna bathing until an increase in rectal temperature of 1.2°C was observed. It was shown that group A performed physical exercise for a longer period of time, which elicited significantly higher amounts of work performed in the stress test. Both forms of overheating caused a significant decrease in BM and a significant change in plasma volume, while greater dehydration was observed after active overheating. Changes observed in group A were higher than in group N. MCV levels were initially higher in group A. The levels in both groups decreased after sauna bathing, although in non-athletes the decrease was greater. Both forms of overheating increased Hb, HCT, and SBP, while only the non-athletic group showed a decrease in DBP after the exercise stress test. However, a decrease in DBP was observed in both groups after sauna bathing. The PSI increased after both tests, yet to a higher extent after the stress test than after sauna bathing. The PSI was negatively correlated with VO2max in both groups. The increase in cortisol concentration was higher after sauna bathing. There was a correlation between cortisol levels and the work performed during the stress test in group A. Endurance training resulted in more efficient thermoregulatory mechanisms in athletes.

Sympathetic Nerve Activity and Blood Pressure Response to Exercise in Peripheral Artery Disease: From Molecular Mechanisms, Human Studies, to Intervention Strategy Development

Sympathetic nerve activity (SNA) regulates the contraction of vascular smooth muscle and leads to a change in arterial blood pressure (BP). It was observed that SNA, vascular contractility, and BP are heightened in patients with peripheral artery disease (PAD) during exercise. The exercise pressor reflex (EPR), a neural mechanism responsible for BP response to activation of muscle afferent nerve, is a determinant of the exaggerated exercise-induced BP rise in PAD. Based on recent results obtained from a series of studies in PAD patients and a rat model of PAD, this review will shed light on SNA-driven BP response and the underlying mechanisms by which receptors and molecular mediators in muscle afferent nerves mediate the abnormalities in autonomic activities of PAD. Intervention strategies, particularly non-pharmacological strategies, improving the deleterious exercise-induced SNA and BP in PAD, and enhancing tolerance and performance during exercise will also be discussed.

Physiological Response to Thermal Stress in Obese vs. Non-Obese Physically Inactive Men

The effects of thermal stress on the physiological parameters of obese subjects remain insufficiently researched. The objective of this study was to determine the influence of sauna bathing on the physiological parameters of obese and non-obese physically inactive men. Sixty volunteers aged 18−24 years (20.85 ± 1.46) were divided into two groups (group I—normal body mass, group II—class 1 obesity) for a comparative analysis. Somatic features and body composition were determined before sauna, and blood pressure was measured before and after sauna. Physiological parameters were monitored before and during the sauna session. The average values of body mass, body mass index, body surface area, and weight-to-height ratio were significantly higher (p < 0.001) in obese men (by 28.39 kg, 8.7 kg/m2, 0.34 m2, and 0.13, respectively) than in the normal weight group. Similar observations were made in an analysis of the remaining body composition parameters. The values of physiological parameters (heart rate, systolic and diastolic blood pressure, energy expenditure, oxygen uptake, excess post-exercise oxygen consumption, respiratory rate) were significantly (p < 0.001) higher in obese subjects. However, the observed physiological changes were within the expected norm; therefore, a 10 min sauna session is safe for young men regardless of their body fat levels.

Overheating or overcooling: heat transfer in the spot to fight against the pandemic obesity

The prevalence of obesity has nearly doubled worldwide over the past three and a half decades, reaching pandemic status. Obesity is associated with decreased life expectancy and with an increased risk of metabolic, cardiovascular, nervous system diseases. Hence, understanding the mechanisms involved in the onset and development of obesity is mandatory to promote planned health actions to revert this scenario. In this review, common aspects of cold exposure, a process of heat generation, and exercise, a process of heat dissipation, will be discussed as two opposite mechanisms of obesity, which can be oversimplified as caloric conservation. A common road between heat generation and dissipation is the mobilization of Free Faty Acids (FFA) and Carbohydrates (CHO). An increase in energy expenditure (immediate effect) and molecular/metabolic adaptations (chronic effect) are responses that depend on SNS activity in both conditions of heat transfer. This cycle of using and removing FFA and CHO from blood either for heat or force generation disrupt the key concept of obesity: energy accumulation. Despite efforts in making the anti-obesity pill, maybe it is time to consider that the world's population is living at thermoneutrality since temperature-controlled places and the lack of exercise are favoring caloric accumulation.

The Effects of Repeated Thermal Stress on the Physiological Parameters of Young Physically Active Men Who Regularly Use the Sauna: A Multifactorial Assessment

The aim of this study was to determine the effects of thermal stress (TS) on changes in blood biochemical parameters and fluid electrolyte levels in young adult men with moderate and high levels of physical activity. Thirty men (22.67 ± 2.02 years) were exposed to four 12-min sauna sessions (temperature: 90–91 °C; relative humidity: 14–16%) with four 6-min cool-down breaks. The evaluated variables were anthropometric, physiological, and hematological characteristics. The mean values of HR_avg (102.5 bpm) were within the easy effort range, whereas HR_peak (143.3 bpm) values were within the very difficult effort range. A significant increase was noted in pO2 (p < 0.001), total cholesterol (p < 0.008), HDL (p < 0.006) and LDL cholesterol (p < 0.007). Significant decreases were observed in the SBP (by 9.7 mmHg), DBP (by 6.9 mmHg) (p < 0.001), pH (p < 0.001), aHCO₃- (p < 0.005), sHCO3- (p < 0.003), BE (ecf) (p < 0.022), BE (B), ctCO₂ (for both p < 0.005), glucose (p < 0.001), and LA (p < 0.036). High 72-min TS did not induce significant changes in the physiological parameters of young and physically active men who regularly use the sauna, excluding significant loss of body mass. We can assume that relatively long sauna sessions do not disturb homeostasis and are safe for the health of properly prepared males.

TRP Channels as Sensors of Aldehyde and Oxidative Stress

The transient receptor potential (TRP) cation channel superfamily comprises more than 50 channels that play crucial roles in physiological processes. TRP channels are responsive to several exogenous and endogenous biomolecules, with aldehydes emerging as a TRP channel trigger contributing to a cellular cascade that can lead to disease pathophysiology. The body is not only exposed to exogenous aldehydes via tobacco products or alcoholic beverages, but also to endogenous aldehydes triggered by lipid peroxidation. In response to lipid peroxidation from inflammation or organ injury, polyunsaturated fatty acids undergo lipid peroxidation to aldehydes, such as 4-hydroxynonenal. Reactive aldehydes activate TRP channels via aldehyde-induced protein adducts, leading to the release of pro-inflammatory mediators driving the pathophysiology caused by cellular injury, including inflammatory pain and organ reperfusion injury. Recent studies have outlined how aldehyde dehydrogenase 2 protects against aldehyde toxicity through the clearance of toxic aldehydes, indicating that targeting the endogenous aldehyde metabolism may represent a novel treatment strategy. An addition approach can involve targeting specific TRP channel regions to limit the triggering of a cellular cascade induced by aldehydes. In this review, we provide a comprehensive summary of aldehydes, TRP channels, and their interactions, as well as their role in pathological conditions and the different therapeutical treatment options.

The effect of salt-water bath in the management of treatment-related peripheral neuropathy in cancer patients receiving taxane and platinum-based treatment

OBJECTIVES

In a clinical setting, patients have been observed to complain of discomfort and to discontinue treatment because of chemotherapy-induced peripheral neuropathy. This experimental study was conducted to determine the effect of a salt-water bath in the management of chemotherapy-induced peripheral neuropathy.

METHOD

One hundred and three patients who received taxane and platinum-based chemotherapy due to cancer and developed peripheral neuropathy associated with the treatment between December 2018 and June 2020 were included in the study. The patients were assigned to the control and experimental groups (1-warm salt-water and 2-cold salt-water) following the randomization checklist. While control groups did not receive any interventions, the patients in the salt-water group were asked to apply warm (41 °C) or cold-water (23-26 °C) baths to their hands/feet for 30 min every other day for 14 days. The data were collected at the beginning of the study and at the end of its first and second weeks using the Patient Information Form and National Cancer Institute (NCI)-CTCAE v5.0 toxicity criteria as well as the EORTC QLQ-C30 and EORTC QLQ-CIPN20 quality of life scales.

RESULTS

The patients had a mean age of 55.6 ± 10.3, and most of them were treated following a breast cancer diagnosis. At the beginning of the study, Grade 3 peripheral neuropathy severity and quality of life scores of the cold/warm salt-water and control groups were similar. Due to repeated follow-ups, it was determined that the peripheral neuropathy severity decreased and the quality of life scores increased statistically significantly in the patients in the cold salt-water bath group compared to the control group.

CONCLUSION

This study's results suggest that a cold salt-water bath can be an effective approach in managing the development of peripheral neuropathy due to taxane and platinum-based treatment.

Endocrine Effects of Repeated Hot Thermal Stress and Cold Water Immersion in Young Adult Men

The aim of the study was to determine the effect of repeated hot thermal stress and cold water immersion on the endocrine system of young adult men with moderate and high levels of physical activity (PA). The research was conducted on 30 men aged 19–26 years (mean: 22.67 ± 2.02) who attended four sauna sessions of 12 min each (temperature: 90−91°C; relative humidity: 14–16 %). Each sauna session was followed by a 6-min cool-down break during which the participants were immersed in cold water (10−11°C) for 1 min. Testosterone (TES), cortisol (COR), dehydroepiandrosterone sulfate (DHEA-S), and prolactin (PRL) levels were measured before and after the sauna bath. The participants’ PA levels were evaluated using the International Physical Activity Questionnaire. Serum COR levels decreased significantly (p < .001) from 13.61 to 9.67 µg/ml during 72 min of sauna treatment. No significant changes (p >.05) were noted in the concentrations of the remaining hormones: TES increased from 4.04 to 4.24 ng/ml, DHEA-S decreased from 357.5 to 356.82 µg/ml, and PRL decreased from 14.50 to 13.71 ng/ml. After sauna, a greater decrease in COR concentrations was observed in males with higher baseline COR levels, whereas only a minor decrease was noted in participants with very low baseline COR values (r =−0.673, p <.001). Repeated use of Finnish sauna induces a significant decrease in COR concentrations, but does not cause significant changes in TES, DHEA-S, or PRL levels. Testosterone concentrations were higher in men characterized by higher levels of PA, both before and after the sauna bath.

Transient receptor potential vanilloid 2 mediates the inhibitory effect of far-infrared irradiation on adipogenic differentiation of tonsil-derived mesenchymal stem cells

AIMS

Far-infrared (FIR) irradiation inhibits adipogenic differentiation of tonsil-derived mesenchymal stem cells (TMSCs) by activating Ca²⁺-dependent protein phosphatase 2B (PP2B), but it stimulates osteogenic differentiation in a PP2B-independent pathway. We investigated the potential involvement of transient receptor potential vanilloid (TRPV) channels, a well-known Ca²⁺-permeable channel, in the effects of FIR irradiation on adipogenic or osteogenic differentiation of TMSCs.

METHODS

TMSCs, in the absence or presence of activators or inhibitors, were exposed to FIR irradiation followed by adipogenic or osteogenic differentiation, which was assessed using Oil red O or Alizarin red S staining, respectively. RT-PCR, qRT-PCR, and Western blotting were used to determine gene and protein expression of calcium channels and adipocyte-specific markers.

RESULTS

Treatment with the calcium ionophore ionomycin simulated the inhibitory effect of FIR irradiation on adipogenic differentiation but had no effect on osteogenic differentiation, indicating the involvement of intracellular Ca²⁺ in adipogenic differentiation. Inhibition of pan-TRP channels using ruthenium red reversed the FIR irradiation-induced inhibition of adipogenic differentiation. Among the TRP channels tested, inhibition of the TRPV2 channel by tranilast or siRNA against TRPV2 attenuated the inhibitory effect of FIR irradiation on adipogenic differentiation, accompanied by a decrease in intracellular Ca²⁺ levels. By contrast, activation of the TRPV2 channel by probenecid simulated FIR irradiation-induced inhibition of adipogenic differentiation. Expectedly, the stimulatory effect of FIR irradiation on osteogenic differentiation was independent of the TRPV2 channel.

CONCLUSION

Our data demonstrate that the TRPV2 channel is a sensor/receptor for the inhibited adipogenic differentiation of TMSCs associated with FIR irradiation.

The Cardiometabolic Health Benefits of Sauna Exposure in Individuals with High-Stress Occupations. A Mechanistic Review

Components of the metabolic syndrome (i.e., hypertension, insulin resistance, obesity, atherosclerosis) are a leading cause of death in the United States and result in low-grade chronic inflammation, excessive oxidative stress, and the eventual development of cardiometabolic diseases (CMD). High-stress occupations (HSO: firefighters, police, military personnel, first responders, etc.) increase the risk of developing CMD because they expose individuals to chronic and multiple stressors (i.e., sleep deprivation, poor nutrition habits, lack of physical activity, psychological stress). Interestingly, heat exposure and, more specifically, sauna bathing have been shown to improve multiple markers of CMD, potentially acting as hormetic stressors, at the cellular level and in the whole organism. Therefore, sauna bathing might be a practical and alternative intervention for disease prevention for individuals with HSO. The purpose of this review is to detail the mechanisms and pathways involved in the response to both acute and chronic sauna bathing and collectively present sauna bathing as a potential treatment, in addition to current standard of care, for mitigating CMD to both clinicians and individuals serving in HSO.

Hot water immersion acutely increases postprandial glucose concentrations

Chronic hot water immersion (HWI) confers health benefits, including a reduction in fasting blood glucose concentration. Here we investigate acute glycemic control immediately after HWI. Ten participants (age: 25 ± 6 years, body mass: 84 ± 14 kg, height 1.85 ± 0.09 m) were immersed in water (39°C) to the neck (HWI) or sat at room temperature (CON) for 60 min. One hour afterward they underwent an oral glucose tolerance test (OGTT), with blood collected before and after HWI/CON and during the 2 h OGTT. Glucose incremental area under the curve (iAUC) during the OGTT was higher for HWI (HWI 233 ± 88, CON 156 ± 79 mmol·L^-1 ·2 h, P = 0.02). Insulin iAUC did not differ between conditions (HWI 4309 ± 3660, CON 3893 ± 3031 mU·L^-1 ·2 h, P = 0.32). Core temperature increased to 38.6 ± 0.2°C during HWI, but was similar between trials during the OGTT (HWI 37.0 ± 0.2, CON 36.9 ± 0.4°C, P = 0.34). Directly following HWI, plasma average adrenaline and growth hormone concentrations increased 2.7 and 10.7-fold, respectively (P < 0.001). Plasma glucagon-like peptide-1, peptide YY, and acylated ghrelin concentrations were not different between trials during the OGTT (P > 0.11). In conclusion, HWI increased postprandial glucose concentration to an OGTT, which was accompanied by acute elevations of stress hormones following HWI. The altered glycemic control appears to be unrelated to changes in gut hormones during the OGTT.

Designing a Smart Bath Assistive Device Based on Measuring Inner Water Temperature for Bathing Temperature Monitoring

Today, taking a bath is not only a means to keep clean, but also to reduce fatigue and stress. However, taking a bath with hot water for a long time can also be dangerous, leading to scalding or even a heart attack. To prevent these risks, several studies based on measuring bio-signals have been conducted, but due to high prices, difficulty of use, and restricted functions, these studies' recommendations cannot be easily adopted by the public. Therefore, developing accurate methods to measure bathing temperature and bathing time should be the most direct approach to solve these problems. In this study, a smart bath assistive device based on an inner water temperature measurement function is proposed. Prior to development of the device, a bathing environment was emulated with six temperature sensors affixed to different depths to find the optimal depth for measuring bathing temperature. According to the measurement results, the device was designed in a mushroom shape with the cap part floating on the water's surface and housing the electronic components, and temperature sensors within the stem part were immersed in the water approximately 5 cm below the surface to measure the inner water temperature. Due to the low-power consuming Advanced RISC Machine (ARM) processor and waterproof design, the device is able to float in hot water and monitor the bathing temperature variation over a long period of time. The device was compared alongside a commercial analog bathing thermometer to verify the performance of temperature measurements. In addition, a compensation algorithm was developed and programmed into the device to improve the accuracy of measurements. Processed data is transmitted by Bluetooth to a dedicated Android app for data display and storage. The final results show that the proposed device is highly accurate and stable for monitoring bathing temperature.

Hand heating lowers postprandial blood glucose concentrations: A double-blind randomized controlled crossover trial

OBJECTIVES

Examine effect of single hand heating with and without negative pressure on fasting blood glucose (FBG) and postprandial blood glucose (PBG).

DESIGN

Double-blind randomized controlled trial with crossover design.

SUBJECTS

FBG experiment: 17 healthy subjects (4 males). PBG experiment: 13 healthy subjects (1 males).

INTERVENTIONS

Devices included one providing heat only, one heat and negative pressure, and one acting as a sham. For the FBG experiment the devices were used for 30 min. For the PBG experiment the devices were used for one hour during an oral glucose tolerance test (OGTT).

OUTCOME MEASURES

Blood glucose measurements were used to determine change in FBG, peak PBG, area under the curve (AUC), and incremental AUC (iAUC).

RESULTS

Temperature: Change in tympanic temperature was ≤ 0.15 °C for all trials. FBG: There was no effect on FBG. PBG: Compared to the sham device the heat plus vacuum and heat only device lowered peak blood glucose by 16(31)mg/dL, p = 0.092 and 18(28)mg/dL, p = 0.039, respectively. AUC and iAUC: Compared to the sham device, the heat plus vacuum device and heat only device lowered the AUC by 5.1(15.0)%, p = 0.234 and 7.9(11.1)%, p = 0.024 respectively and iAUC by 17.2(43.4)%, p = 0.178 and 20.5(34.5)%, p = 0.054, respectively.

CONCLUSIONS

Heating a single hand lowers postprandial blood glucose in healthy subjects.

Far-infrared Ray-mediated Antioxidant Potentials are Important for Attenuating Psychotoxic Disorders

Far-infrared ray (FIR) is an electromagnetic wave that produces various health benefits against pathophysiological conditions, such as diabetes mellitus, renocardiovascular disorders, stress, and depression etc. However, the therapeutic ap-plication on the FIR-mediated protective potentials remains to be further extended. To achieve better understanding on FIR-mediated therapeutic potentials, we summarized additional findings in the present study that exposure to FIR ameliorates stressful condition, memory impairments, drug dependence, and mitochondrial dysfunction in the central nervous system. In this review, we underlined that FIR requires modulations of janus kinase 2 / signal transducer and activator of transcription 3 (JAK2/STAT3), nuclear factor E2-related factor 2 (Nrf-2), muscarinic M1 acetylcholine receptor (M1 mAChR), dopamine D1 receptor, protein kinase C δ gene, and glutathione peroxidase-1 gene for exerting the protective potentials in response to neuropsychotoxic conditions

Exercise heat acclimation causes post-exercise hypotension and favorable improvements in lipid and immune profiles: A crossover randomized controlled trial

BACKGROUND

Passive hyperthermic exposure causes an acute hypotensive response following the cessation of heat stress. Chronic heat stress is well documented in animal studies to instigate metabolic and lipid alterations. However, it is unknown if exercise-heat acclimation also causes favorable chronic blood pressure, lipid, and immune responses in humans.

PURPOSE

This project tested the hypothesis that 10-day exercise-heat acclimation (HA) would cause greater post-exercise reductions in arterial blood pressure and favorable metabolic, lipid, and immune responses compared to 10-day exercise under neutral conditions (CON).

METHODS

Thirteen healthy sedentary participants (8M/5F, 28 ± 6y, 78 ± 17 kg), completed a 10-day (90 min/day exercise bout) clamped hyperthermia HA (increase internal temperature 1.5 °C, in 42 °C, 28% Rh) and control (CON: 23 °C, 42% Rh) protocols in a counterbalanced design with a 2 month washout. Pre- and post-exercise HA/CON blood pressures were taken 1-h post-exercise on exercise days 1 and 10. Metabolic, lipid and immune panels were taken pre-post HA/CON.

RESULTS

Exercise under heat stress had greater post-exercise hypotension (systolic; -6 mmHg, diastolic; -8 mmHg; and mean arterial pressure; -7 mmHg) on both days 1 and 10 compared to exercise under neutral conditions (main effect for condition, P ≤ 0.004). Only from pre-to-post HA, total cholesterol (168 ± 19 to 157 ± 15; P < 0.03) and triglycerides (137 ± 45 to 111 ± 30; P < 0.03) were reduced, while absolute lymphocytes (-26%), monocytes (-22%), and basophils (-49%) significantly decreased (each P ≤ 0.04). Relative values of neutrophils increased (18%) and lymphocytes decreased (-20%) only after HA (P ≤ 0.04).

CONCLUSION

These data indicate that exercise in the heat (regardless of acclimation status) causes a profound post-exercise hypotensive response, while HA causes favorable lipid, and immune profile changes. Further examination of exercise-heat acclimation on vascular, metabolic, and immune responses will offer insight for benefits in other clinical populations with vascular, metabolic and immune dysfunction.

Correlations between Repeated Use of Dry Sauna for 4 x 10 Minutes, Physiological Parameters, Anthropometric Features, and Body Composition in Young Sedentary and Overweight Men: Health Implications

Background

The effect of thermal stress on the physiological parameters of young overweight and sedentary men who sporadically use the sauna remains insufficiently investigated.

Aim

The aim of the study was to determine the effect of sauna bathing on the physiological parameters of young overweight, physically inactive men and to test the correlations between physiological parameters versus anthropometric features and body composition parameters.

Materials and Methods

Forty-five overweight and sedentary men aged 20.76±2.4 y were exposed to four sauna sessions of 10 minutes each (temperature: 90-91°C; relative humidity: 14-16 %) with four 5-minute cool-down breaks. Body composition was determined before sauna, and body mass and blood pressure were measured before and after sauna. Physiological parameters were monitored during four 10-minute sauna sessions.

Results

A significant (p<0.0001) increase in all analyzed physiological parameters was observed during four successive 10-minute sauna sessions. Heart rate, energy expenditure, blood pressure, and body mass loss were most strongly correlated with anthropometric parameters (body mass, body mass index, and body surface area) and body composition parameters (percent body fat, body fat mass, and visceral fat level). The 60-minute treatment resulted in a significant reduction in body mass (0.65 kg).

Conclusions

Repeated use of Finnish sauna induces significant changes in the physiological parameters of young sedentary overweight men, and these changes are intensified during successive treatments. Deleterious cardiovascular adaptations were most prevalent in men characterized by the highest degree of obesity and the largest body size.

BODY MASS LOSS IN DRY SAUNA AND HEART RATE RESPONSE TO HEAT STRESS

ABSTRACT Objectives: The aim of the study was to determine the effects of sauna-induced heat exposure on body mass loss (BML) and its relationships with basic anthropometric and physiological variables. Methods: The sample comprised 230 healthy adult males aged 21.0 ± 1.08 years (age range: 20.0–24.5 years). Body surface area (BSA) was determined and two groups of individuals with high BSA (BSAH; n = 58) and low BSA (BSAL; n = 74) were extracted. The intervention consisted of two 10-min dry sauna sessions separated by a 5-min interlude. Pre-, peri-, and post-sauna measures of nude body mass (BM) and heart rate (HR) were taken. Results: BML differed between BSA groups by 0.28 kg (74.81%). Absolute and relative BML most strongly correlated with BM and BSA (p < 0.001). Among the four considered height–weight indexes, the Quetelet I Index and Body Mass Index showed the strongest associations (p < 0.001) with BML whereas the weakest were with the Rohrer Index (p < 0.01) and Slenderness Index (p < 0.05). Compared with BML, differences in HR were relatively minor (from 9.90% to 18.07%) and a significant association was observed between BML and HR at rest (p < 0.01) and in 10th and 20th min of sauna bathing (p < 0.001). Conclusions: The magnitude of BML in healthy adult males after passive heat exposure was dependent on BM and concomitantly BSA. The physiological cost of dry sauna-induced thermal strain (as assessed by BML and HR) is greater in individuals with high BM and BSA. BM and HR monitoring is also recommended in order to minimize the risk of homeostatic imbalance and cardiovascular events and this cohort should more frequently cool the body and consume a greater volume of fluids during sauna bathing. Evidence Level II; Prospective comparative study.

Exercise, heat shock proteins and insulin resistance

Best known as chaperones, heat shock proteins (HSPs) also have roles in cell signalling and regulation of metabolism. Rodent studies demonstrate that heat treatment, transgenic overexpression and pharmacological induction of HSP72 prevent high-fat diet-induced glucose intolerance and skeletal muscle insulin resistance. Overexpression of skeletal muscle HSP72 in mice has been shown to increase endurance running capacity nearly twofold and increase mitochondrial content by 50%. A positive correlation between HSP72 mRNA expression and mitochondrial enzyme activity has been observed in human skeletal muscle, and HSP72 expression is markedly decreased in skeletal muscle of insulin resistant and type 2 diabetic patients. In addition, decreased levels of HSP72 correlate with insulin resistance and non-alcoholic fatty liver disease progression in livers from obese patients. These data suggest the targeted induction of HSPs could be a therapeutic approach for preventing metabolic disease by maintaining the body's natural stress response. Exercise elicits a number of metabolic adaptations and is a powerful tool in the prevention and treatment of insulin resistance. Exercise training is also a stimulus for increased HSP expression. Although the underlying mechanism(s) for exercise-induced HSP expression are currently unknown, the HSP response may be critical for the beneficial metabolic effects of exercise. Exercise-induced extracellular HSP release may also contribute to metabolic homeostasis by actively restoring HSP72 content in insulin resistant tissues containing low endogenous levels of HSPs.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.

Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review

Introduction

Many health benefits are claimed by individuals and facilities promoting sauna bathing; however the medical evidence to support these claims is not well established. This paper aims to systematically review recent research on the effects of repeated dry sauna interventions on human health.

Methods

A systematic search was made of medical databases for studies reporting on the health effects of regular dry sauna bathing on humans from 2000 onwards. Risk of bias was assessed according to the Cochrane Collaboration guidelines.

Results

Forty clinical studies involving a total of 3855 participants met the inclusion criteria. Only 13 studies were randomized controlled trials and most studies were small (n < 40). Reported outcome measures were heterogeneous with most studies reporting beneficial health effects. Only one small study (n = 10) reported an adverse health outcome of disrupted male spermatogenesis, demonstrated to be reversible when ceasing sauna activity.

Conclusions

Regular dry sauna bathing has potential health benefits. More data of higher quality is needed on the frequency and extent of adverse side effects. Further study is also needed to determine the optimal frequency and duration of distinct types of sauna bathing for targeted health effects and the specific clinical populations who are most likely to benefit.

Response of Local Nitric Oxide Release to Manual Acupuncture and Electrical Heat in Humans: Effects of Reinforcement Methods

This study was to examine the influences of manual acupuncture (MA) and electrical heat corresponding to reinforcing methods on nitric oxide (NO) release over the skin regions in humans. A device with collecting solution was taped to the skin surface along pericardium (PC) or lung (LU) meridian. Acupuncture needles were gently inserted into PC 4 with reinforcing stimulation (low force/rate) for 20 minutes in the MA group. LU11 on the finger was heated (43-44°C) by electrical heat for 20 minutes. Biocapture was consecutively conducted for two 20-minute intervals during and after each treatment. Total nitrite and nitrate (NO _x^-) in the collecting samples were quantified using chemiluminescence in blinded fashion. Baseline NO _x^- levels are higher and tended to be higher over PC and LU acupoints during the 1st biocapture. NO _x^- levels over PC regions were consistently increased by MA during both intervals. NO _x^- concentrations over LU acupoints were increased and tended to be increased by electrical heat in the 1st and 2nd biocapture. The results suggest that reinforcing MA and electrical heat induce NO released from the local skin regions with higher levels at acupoints, which improve local circulation and contribute to the beneficial effects of the therapies.

Obese type 2 diabetics have a blunted hypotensive response to acute hyperthermia therapy that does not affect the perception of thermal stress or physiological strain compared to healthy adults

PURPOSE

The objective of this study was to test the hypothesis that a hyperthermia-hypotensive challenge via whole body hot water immersion would alter the perception of hyperthermia and physiological strain in obese type 2 diabetics (T2DM) compared to healthy non-obese (HC) individuals. Additionally, we hypothesize that the mechanisms would be attributed to impaired blood pressure adjustments and afferent signals (via changes in internal and mean skin temperatures).

METHODS

In random order, eleven obese T2DM (50±12y, 45±7% fat mass, 7.5±1.8% HbA1c) and nine similar aged (41±14y, P>0.05) HC non-obese (33±8% fat mass, P<0.01) non-diabetic (5.3±0.4% HbA1c, P<0.01) underwent a 60min bout of whole body passive hyperthermia followed by 60min of recovery or a 2h resting control condition. The perception of thermal sensation (TS, scale range: 1-13), calculated physiological strain (PSI), internal (Tre, rectal) and mean skin (Tsk) temperatures, heart rate (HR) and blood pressures (BP) were the primary dependent variables.

RESULTS

Hyperthermia similarly increased Tre by 1.4±0.4°C, Tsk by 6.5±0.8°C and HR by 34±8bpm in both groups (P>0.5). Hyperthermia reduced diastolic BP (27% in T2DM and 33% in HC, P<0.05) and mean arterial BP (reduced by 15% in T2DM and by 19% in HC) relative to control conditions (P<0.05). The reduction of mean arterial BP area under the curve was attenuated in T2DM (12%) compared to HC (30%) (group×condition, P<0.01). TS and PSI during hyperthermia were not different between groups. Pearson product correlation reported strong correlations (r=0.69-0.89) with Tre and Tsk with TS in both populations. The linear stepwise regression analysis revealed similar relative contributions for Tre (~60%) and Tsk (~40%) on TS for both groups.

CONCLUSIONS

These data indicate that obese T2DM with moderate metabolic control have an attenuated hyperthermia-hypotensive response that does not affect TS and PSI. This also may suggest behavioral thermoregulation is intact in this study group.

An acute bout of whole body passive hyperthermia increases plasma leptin, but does not alter glucose or insulin responses in obese type 2 diabetics and healthy adults

Acute and chronic hyperthermic treatments in diabetic animal models repeatedly improve insulin sensitivity and glycemic control. Therefore, the purpose of this study was to test the hypothesis that an acute 1h bout of hyperthermic treatment improves glucose, insulin, and leptin responses to an oral glucose challenge (OGTT) in obese type 2 diabetics and healthy humans. Nine obese (45±7.1% fat mass) type 2 diabetics (T2DM: 50.1±12y, 7.5±1.8% HbA1c) absent of insulin therapy and nine similar aged (41.1±13.7y) healthy non-obese controls (HC: 33.4±7.8% fat mass, P<0.01; 5.3±0.4% HbA1c, P<0.01) participated. Using a randomized design, subjects underwent either a whole body passive hyperthermia treatment via head-out hot water immersion (1h resting in 39.4±0.4°C water) that increased internal temperature above baseline by ∆1.6±0.4°C or a control resting condition. Twenty-four hours post treatments, a 75g OGTT was administered to evaluate changes in plasma glucose, insulin, C-peptide, and leptin concentrations. Hyperthermia itself did not alter area under the curve for plasma glucose, insulin, or C-peptide during the OGTT in either group. Fasting absolute and normalized (kg·fat mass) plasma leptin was significantly increased (P<0.01) only after the hyperthermic exposure by 17% in T2DM and 24% in HC groups (P<0.001) when compared to the control condition. These data indicate that an acute hyperthermic treatment does not improve glucose tolerance 24h post treatment in moderate metabolic controlled obese T2DM or HC individuals.

Acute Thermotherapy Prevents Impairments in Cutaneous Microvascular Function Induced by a High Fat Meal

We tested the hypothesis that a high fat meal (HFM) would impair cutaneous vasodilation, while thermotherapy (TT) would reverse the detrimental effects. Eight participants were instrumented with skin heaters and laser-Doppler (LD) probes and tested in three trials: control, HFM, and HFM + TT. Participants wore a water-perfused suit perfused with 33°C (control and HFM) or 50°C (HFM + TT) water. Participants consumed 1 g fat/kg body weight. Blood samples were taken at baseline and two hours post-HFM. Blood pressure was measured every 5-10 minutes. Microvascular function was assessed via skin local heating from 33°C to 39°C two hours after HFM. Cutaneous vascular conductance (CVC) was calculated and normalized to maximal vasodilation (%CVCmax). HFM had no effect on initial peak (48 ± 4 %CVCmax) compared to control (49 ± 4 %CVCmax) but attenuated the plateau (51 ± 4 %CVCmax) compared to control (63 ± 4 %CVCmax, P < 0.001). Initial peak was augmented in HFM + TT (66 ± 4 %CVCmax) compared to control and HFM (P < 0.05), while plateau (73 ± 3 % CVCmax) was augmented only compared to the HFM trial (P < 0.001). These data suggest that HFM negatively affects cutaneous vasodilation but can be minimized by TT.

Heat stress acutely activates insulin-independent glucose transport and 5'-AMP-activated protein kinase prior to an increase in HSP72 protein in rat skeletal muscle

Heat stress (HS) stimulates heat shock protein (HSP) 72 mRNA expression, and the period after an increase in HSP72 protein is characterized by enhanced glucose metabolism in skeletal muscle. We have hypothesized that, prior to an increase in the level of HSP72 protein, HS activates glucose metabolism by acutely stimulating 5'-AMP-activated protein kinase (AMPK). Rat epitrochlearis muscle was isolated and incubated either with or without HS (42°C) for 10 and 30 min. HS for 30 min led to an increase in the level of Hspa1a and Hspa1b mRNA but did not change the amount of HSP72 protein. However, HS for both 10 and 30 min led to a significant increase in the rate of 3-O-methyl-d-glucose (3MG) transport, and the stimulatory effect of 3MG transport was completely blocked by cytochalasin B. HS-stimulated 3MG transport was also inhibited by dorsomorphin but not by wortmannin. HS led to a decrease in the concentration of ATP, phosphocreatine, and glycogen, to an increase in the level of phosphorylation of AMPKα Thr(172), and to an increase in the activity of both AMPKα1 and AMPKα2. HS did not affect the phosphorylation status of insulin receptor signaling or Ca(2+)/calmodulin-dependent protein kinase II. These results suggest that HS acts as a rapid stimulator of insulin-independent glucose transport, at least in part by stimulating AMPK via decreased energy status. Although further research is warranted, heat treatment of skeletal muscle might be a promising method to promote glucose metabolism acutely.

Heat shock proteins and heat therapy for type 2 diabetes: pros and cons

PURPOSE OF REVIEW

Heat therapy, such as sauna and hot tub, has become an increasingly regular therapeutical practice around the world since several studies have shown benefits of heat therapy in metabolic and cardiovascular diseases. The use of heat therapy in people with type 2 diabetes mellitus revealed a striking reduction of 1% unit in the glycated hemoglobin, suggesting this therapy for the treatment of diabetes. Herein, we shall discuss the use of heat therapy and the mechanisms involved, and suggest a provisional guide for the use of heat therapy in obesity and diabetes.

RECENT FINDINGS

Human studies indicate that heat therapy reduces fasting glycemia, glycated hemoglobin, body weight, and adiposity. Animal studies have indicated that nitric oxide and the increase in heat shock protein 70 expression is involved in the improvements induced by heat therapy on insulin sensitivity, adiposity, inflammation, and vasomotricity.

SUMMARY

Heat therapy is a promising and inexpensive tool for the treatment of obesity and diabetes. We proposed that transient increments in nitric oxide and heat shock protein 70 levels may explain the benefits of heat therapy. We suggest that heat therapy (sauna: 80-100°C; hot tub: at 40°C) for 15 min, three times a week, for 3 months, is a safe method to test its efficiency.

Effect of a 12-day balneotherapy programme on pain, mood, sleep, and depression in healthy elderly people

BACKGROUND

The main purpose of this study is to analyze the effect of a 12-day balneotherapy programme on pain, mood state, sleep, and depression in older adults.

METHODS

In this study, 52 elderly adults from different areas of Spain participated in a social hydrotherapy programme created by the government's Institute for Elderly and Social Services, known as IMSERSO; participants included 23 men (age, 69.74 ± 5.19 years) and 29 women (age, 70.31 ± 6.76 years). Pain was analyzed using the visual analogue scale. Mood was assessed using the Profile of Mood Status. Sleep was assessed using the Oviedo Sleep Questionnaire. Depression was assessed using the Geriatric Depression Scale. The balneotherapy programme was undertaken at Balneario San Andrés (Jaén, Spain). The water at Balneario San Andrés, according to the Handbook of Spanish Mineral Water, is a hypothermic (≥20°C) hard water of medium mineralization, with bicarbonate, sulfate, sodium, and magnesium as the dominant ions.

RESULTS

Balneotherapy produced significant improvements (P < 0.05) for all variables (pain, mood state, sleep, and depression) in the total sample. A differential effect was found between the sexes regarding pain improvement, with men, but not women, having significantly improvement (P < 0.01) after treatment. With regard to improving mood, sex differences were also shown, with women, but not men, significantly improved (P < 0.05) in both depression and fatigue.

CONCLUSIONS

In conclusion, a 12-day balneotherapy programme has a positive effect on pain, mood, sleep quality, and depression in healthy older people.

The effect of sauna bathing on lipid profile in young, physically active, male subjects

OBJECTIVES

The aim of the study was to evaluate effects of Finnish sauna bathing on lipid profile in healthy, young men.

MATERIAL AND METHODS

Sixteen male subjects (20-23 years) were subjected to 10 sauna bathing sessions in a Finnish sauna every 1 or 2 days. The mean sauna temperature was 90±2°C, while humidity was 5-16%. Each session consisted of three 15-minute parts and a 2-minute cool-down between them. The following measurements were taken before and after the sauna sessions: body mass, heart rate, body skinfold thickness. The percentage fat content and then, the lean body mass were calculated. Total cholesterol, triacylglycerols, lipoprotein cholesterol LDL and HDL were measured in blood samples.

RESULTS

A statistically significant decrease of total cholesterol and LDL cholesterol was observed during 3 weeks of sauna treatment and in the week afterwards. A significant decline in triacylglycerols was found directly after the 1st and 24 h directly after the 10th sauna session. After the 10th sauna session the level of HDL cholesterol remained slightly increased, but this change was not statistically significant. A decrease in blood plasma volume was found directly after the 1st and the last sauna bathing session due to perspiration. An adaptive increase in blood plasma volume was also found after the series of 10 sauna sessions.

CONCLUSIONS

Ten complete sauna bathing sessions in a Finnish sauna caused a reduction in total cholesterol and LDL cholesterol fraction levels during the sessions and a gradual return of these levels to the initial level during the 1st and the 2nd week after the experiment. A small, statistically insignificant increase in HDL-C level and a transient decline in triacylglycerols were observed after those sauna sessions. The positive effect of sauna on lipid profile is similar to the effect that can be obtained through a moderate-intensity physical exercise.

The importance of the cellular stress response in the pathogenesis and treatment of type 2 diabetes

Organisms have evolved to survive rigorous environments and are not prepared to thrive in a world of caloric excess and sedentary behavior. A realization that physical exercise (or lack of it) plays a pivotal role in both the pathogenesis and therapy of type 2 diabetes mellitus (t2DM) has led to the provocative concept of therapeutic exercise mimetics. A decade ago, we attempted to simulate the beneficial effects of exercise by treating t2DM patients with 3 weeks of daily hyperthermia, induced by hot tub immersion. The short-term intervention had remarkable success, with a 1 % drop in HbA1, a trend toward weight loss, and improvement in diabetic neuropathic symptoms. An explanation for the beneficial effects of exercise and hyperthermia centers upon their ability to induce the cellular stress response (the heat shock response) and restore cellular homeostasis. Impaired stress response precedes major metabolic defects associated with t2DM and may be a near seminal event in the pathogenesis of the disease, tipping the balance from health into disease. Heat shock protein inducers share metabolic pathways associated with exercise with activation of AMPK, PGC1-a, and sirtuins. Diabetic therapies that induce the stress response, whether via heat, bioactive compounds, or genetic manipulation, improve or prevent all of the morbidities and comorbidities associated with the disease. The agents reduce insulin resistance, inflammatory cytokines, visceral adiposity, and body weight while increasing mitochondrial activity, normalizing membrane structure and lipid composition, and preserving organ function. Therapies restoring the stress response can re-tip the balance from disease into health and address the multifaceted defects associated with the disease.

Comparison of physiological reactions and physiological strain in healthy men under heat stress in dry and steam heat saunas

The aim of the paper was to follow up major physiological reactions, provoked by heat stress during dry and wet sauna baths. A physical strain index and subjective estimation of heat comfort of subjects who had not taken sauna baths before was also evaluated. Ten healthy males aged 25-28 underwent a dry sauna bath and then after a one-month break they underwent a steam sauna bath. Each time, they entered the sauna chamber 3 times for 15 minutes with five-minute breaks. During breaks they cooled their bodies with a cold shower and then rested in a sitting position. Before and after the baths, body mass and blood pressure were measured. Rectal temperature and heart rate were monitored during the baths. The physiological strain index (PSI) and cumulative heat strain index (CHSI) were calculated. Subjects assessed heat comfort by Bedford's scale. Greater body mass losses were observed after the dry sauna bath compared to the wet sauna (-0.72 vs. -0.36 kg respectively). However, larger increases in rectal temperature and heart rate were observed during the wet sauna bath (38.8% and 21.2% respectively). Both types of sauna baths caused elevation of systolic blood pressure, but changes were greater after the dry one. Diastolic pressure was reduced similarly. Subjective feelings of heat comfort as well as PSI (4.83 ± 0.29 vs. 5.7 ± 0.28) and CHSI (76.3 ± 18.4 vs. 144.6 ± 21.7) were greater during the wet sauna bath. It can be concluded that due to high humidity and reduction of thermoregulation mechanisms, the wet sauna is more stressful for the organism than the dry sauna, where the temperature is higher with low humidity. Both observed indexes (PSI and CHSI) could be appropriate for objective assessment of heat strain during passive heating of the organism.

A clinical study on the role of Agnimanthadi compound and Vashpa Svedana in the management of Sthaulya (obesity)

Currently more than 1 billion adults are overweight (Sthula) and at least 300 million of them are clinically obese. Obesity leads to adverse metabolic effects on blood pressure, cholesterol, triglycerides, and insulin resistance. Present study was planned to assess the role of Agnimanthadi compound containing Agnimantha, Mustaka, Gomutra (cow's urine), and Eranda Patra Kshara and Vashpa Svedana (VS) (generalized steaming) in the management of obesity. 80 patients of Sthaulya (obesity) were selected out of which 67 completed the treatment and they were treated in two groups. Amongst these, 38 patients were treated with Agnimanthadi compound in the dose of 2 gram (four capsules of 500 mg) 3 times a day with lukewarm water before meal and remaining 29 patients were given VS only. The duration of treatment in both groups was 7 weeks with follow-up for 2 months after the completion of treatment. Analysis of the overall effects of both the groups showed that VS provided marked reduction in weight, body mass index, and other signs and symptoms in patients of Sthaulya in comparison to the Agnimanthadi treated group.

Which cleansing care is better, foot bath or shower? Analysis of 236 limb ulcers

Foot baths and showering are two widely used methods to cleanse limb ulcers. However, some clinicians warn that foot baths may contribute to the spread of infection at the ulcer site. This study aimed to retrospectively investigate the relationship between cleansing methods and the limb prognoses of 236 patients with chronic limb ulcers. These patients were divided into two groups according to the method used to cleanse their ulcers, foot bath and showering. Limb prognosis, including loss of all toes and major amputation, was retrospectively analysed. The rates of loss of all toes and major amputation were 53·0% and 30% in the foot bath group, and 35·3% and 18·4% in the showering group, respectively. The rates of loss of all toes (adjusted odds ratios = 2·07; P = 0·0066; 95% confidence intervals, 1·22-3·50) and major amputation (adjusted odds ratio = 1·90; P = 0·037; 95% confidence intervals, 1·03-3·50) were significantly higher in the foot bath group than those in the showering group. Our results demonstrate that showering is preferable to foot baths for the cleansing of chronic limb ulcers. Clinicians should be cautious that inappropriate cleansing may cause ulcer infections to spread.

One-year effectiveness of a 3-week balneotherapy program for the treatment of overweight or obesity

Objective. To assess the one-year effectiveness on weight loss of a 3-week balneotherapy program (BT). Method. A Zelen double consent randomised controlled trial to compare one-year BMI loss between a 3-week BT program versus usual care (UC) for overweight or obese patients (BMI: 27–35 kg/m²), associated or not with a dietary motivational interview (DMI) during the follow-up, using a 2 × 2 factorial design. Main analysis was a per protocol analysis comparing patients attending BT to patients managed by UC, matched on sex, overweight or obese status, DMI randomisation and a propensity score to attend BT or to be managed by UC. Results. From the 257 patients who completed the follow-up, 70 patients of each group could be matched. Mean BMI loss was 1.91 kg/m² [95%CI: 1.46; 2.35] for the BT patients and 0.20 kg/m² [−0.24; 0.64] for the UC patients (P < 0.001), corresponding to a significant BT benefit of 1.71 kg/m² [1.08; 2.33]. There was no significant effect of DMI and no interaction with BT or UC. No adverse reaction was observed for patients attending BT. Conclusion. A 3-week BT program provided a significant one-year benefit over the usual GP dietary advice for overweight and obese patients.

Effect of thermal therapy using hot water bottles on brain natriuretic Peptide in chronic hemodialysis patients

INTRODUCTION

The use of repeated thermal therapy for improving the symptoms of chronic heart failure (CHF) has been recently demonstrated. Usually, thermal therapy requires an infrared dry sauna. However, it is difficult for small clinics to acquire such an expensive and extensive system. The present study assessed the efficacy of its substitution with hot water bottles. Moreover, there are no prior studies demonstrating the efficacy of thermal therapy in hemodialysis patients with CHF.

METHODS

Plasma brain natriuretic peptide (BNP) levels were evaluated in 98 hemodialysis patients in a clinic. Nine patients whose BNP levels were >500 pg/mL agreed to be enrolled in the study and received thermal therapy using hot water bottles.

RESULTS

Plasma BNP levels, a potential marker for CHF, tended to decrease (891 ± 448 to 680 ± 339 pg/mL), but the difference was not significant (P = 0.0845). The oral temperature changed from 36.44 ± 0.45°C to 37.04 ± 0.48°C (+0.597°C, P < 0.0001). No side effects were experienced during the therapy. Moreover, most patients had an improvement in their symptoms and the ability to perform activities of daily living.

CONCLUSION

Thermal therapy using hot water bottles is very safe and tends to reduce plasma BNP levels in hemodialysis patients with CHF.

Insulin Signaling, GSK-3, Heat Shock Proteins and the Natural History of Type 2 Diabetes Mellitus: A Hypothesis

Metabolic syndrome and type 2 diabetes are progressive, indolent, multi-organ diseases. Understanding the abnormalities of heat shock proteins (HSPs) in these diseases is paramount to understanding their pathogenesis. In insulin resistant states and diabetes, heat shock factor 1(HSF-1) is low in insulin sensitive tissues, resulting in low Hsp 60, 70, and 90 levels. We propose that low Hsps levels are the result of decreased insulin action leading to less phosphorylation of PI3K, PKB, and glycogen synthase kinase-3 (GSK-3). Importantly, less GSK-3 phosphorylation (and thus more GSK-3 activity) will lower HSF-1. Low Hsps make organs vulnerable to injury, impair the stress response, accelerate systemic inflammation, raise islet amyloid polypeptide, and increase insulin resistance. Feeding this cycle is excess saturated fat and calorie consumption, hypertension, inactivity, aging, and genetic predisposition- all of which are a associated with high GSK-3 activity and low Hsps. Support for the proposed "vicious" cycle is based on the observation that GSK-3 inhibition and Hsp stimulation result in increased insulin sensitivity, reduced accumulation of degenerative proteins with in the cell, improved wound healing, decreased organ damage and improved recovery from vascular ischemia. Recognizing GSK-3 and Hsps in the pathogenesis of insulin resistance, the central common feature of the metabolic syndrome, and type 2 diabetes will expand our understanding of the disease, offering new therapeutic options.

A Mechanism-Based Approach to Prevention of and Therapy for Fibromyalgia

Fibromyalgia syndrome (FMS) is characterized by pain referred to deep tissues. Diagnosis and treatment of FMS are complicated by a variable coexistence with regional pain, fatigue, sleep disruption, difficulty with mentation, and depression. The widespread, deep pain of FMS can be a consequence of chronic psychological stress with autonomic dysregulation. Stress acts centrally to facilitate pain and acts peripherally, via sympathetic vasoconstriction, to establish painful muscular ischemia. FMS pain, with or without a coexistent regional pain condition, is stressful, setting up a vicious circle of reciprocal interaction. Also, stress interacts reciprocally with systems of control over depression, mentation, and sleep, establishing FMS as a multiple-system disorder. Thus, stress and the ischemic pain it generates are fundamental to the multiple disorders of FMS, and a therapeutic procedure that attenuates stress and peripheral vasoconstriction should be highly beneficial for FMS. Physical exercise has been shown to counteract peripheral vasoconstriction and to attenuate stress, depression, and fatigue and improve mentation and sleep quality. Thus, exercise can interrupt the reciprocal interactions between psychological stress and each of the multiple-system disorders of FMS. The large literature supporting these conclusions indicates that exercise should be considered strongly as a first-line approach to FMS therapy.

Acute effects of a single warm-water bath on serum adiponectin and leptin levels in healthy men: a pilot study

To preliminarily assess the acute effects of a single warm-water bath (WWB) on serum adipokine activity, we measured serum adiponectin, leptin and other metabolic profiles before, immediately after and 30 minutes after WWB in seven healthy male volunteers (mean age, 39.7 ± 6.0 years; mean body mass index, 21.6 ± 1.8 kg/m(2)). The subjects were immersed in tap water at 41°C for 10 minutes. Two weeks later, the same subjects underwent a single WWB with a bath additive that included inorganic salts and carbon dioxide (WWB with ISCO(2)) by the same protocol as for the first WWB. Leptin levels significantly increased immediately after WWB with tap water and ISCO(2) (both P < 0.05), and remained significantly higher than those at baseline even 30 minutes after WWB with tap water (P < 0.05). Adiponectin levels showed a slight, but not significant, increase both immediately after and 30 minutes after WWB with tap water or ISCO(2). Some parameters, such as serum total cholesterol, red blood cell count, hemoglobin and hematocrit significantly increased immediately after WWB with tap water or ISCO(2) (all P < 0.05), but they all returned to the baseline levels 30 minutes after bathing under both conditions. The sublingual temperature rose significantly after 10 minutes of WWB with tap water (0.96 ± 0.16°C relative to baseline, P < 0.01) and after the same duration of WWB with ISCO(2) (1.24 ± 0.34°C relative to baseline, P < 0.01). These findings suggest that a single WWB at 41°C for 10 minutes may modulate leptin and adiponectin profiles in healthy men.

The skin function: a factor of anti-metabolic syndrome

The body's total antioxidant capacity represents a sum of the antioxidant capacity of various tissues/organs. A decrease in the body's antioxidant capacity may induce oxidative stress and subsequent metabolic syndrome, a clustering of risk factors for type 2 diabetes and cardiovascular disease. The skin, the largest organ of the body, is one of the major components of the body's total antioxidant defense system, primarily through its xenobiotic/drug biotransformation system, reactive oxygen species-scavenging system, and sweat glands- and sebaceous glands-mediated excretion system. Notably, unlike other contributors, the skin contribution is variable, depending on lifestyles and ambient temperature or seasonal variations. Emerging evidence suggests that decreased skin's antioxidant and excretory functions (e.g., due to sedentary lifestyles and low ambient temperature) may increase the risk for metabolic syndrome. This review focuses on the relationship between the variability of skin-mediated detoxification and elimination of exogenous and endogenous toxic substances and the development of metabolic syndrome. The potential role of sebum secretion in lipid and cholesterol homeostasis and its impact on metabolic syndrome, and the association between skin disorders (acanthosis nigricans, acne, and burn) and metabolic syndrome are also discussed.

[Mild stress as a means to modulate aging: from fly to human?]

Hormesis is the phenomenon by which adaptive responses to low doses of otherwise harmful conditions improve the functional ability of organisms. Some mild stresses have beneficial effects on longevity, aging and resistance to strong stresses (heat or cold shocks, infection) in Drosophila flies. Studies on rodents are indeed scarce but mild stress seems to be effective in humans because, for instance, patients suffering from angina have a higher survival when confronted with a heart attack. A few studies, in less tragic situations however, suggest that mild stress could have positive effects in elderly people. Performing more experiments on the effects of mild stress in humans would help to know whether it could be used in therapy or to improve healthspan of elderly.

Synchronization of circadian Per2 rhythms and HSF1-BMAL1:CLOCK interaction in mouse fibroblasts after short-term heat shock pulse

Circadian rhythms are the general physiological processes of adaptation to daily environmental changes, such as the temperature cycle. A change in temperature is a resetting cue for mammalian circadian oscillators, which are possibly regulated by the heat shock (HS) pathway. The HS response (HSR) is a universal process that provides protection against stressful conditions, which promote protein-denaturation. Heat shock factor 1 (HSF1) is essential for HSR. In the study presented here, we investigated whether a short-term HS pulse can reset circadian rhythms. Circadian Per2 rhythm and HSF1-mediated gene expression were monitored by a real-time bioluminescence assay for mPer2 promoter-driven luciferase and HS element (HSE; HSF1-binding site)-driven luciferase activity, respectively. By an optimal duration HS pulse (43°C for approximately 30 minutes), circadian Per2 rhythm was observed in the whole mouse fibroblast culture, probably indicating the synchronization of the phases of each cell. This rhythm was preceded by an acute elevation in mPer2 and HSF1-mediated gene expression. Mutations in the two predicted HSE sites adjacent (one of them proximally) to the E-box in the mPer2 promoter dramatically abolished circadian mPer2 rhythm. Circadian Per2 gene/protein expression was not observed in HSF1-deficient cells. These findings demonstrate that HSF1 is essential to the synchronization of circadian rhythms by the HS pulse. Importantly, the interaction between HSF1 and BMAL1:CLOCK heterodimer, a central circadian transcription factor, was observed after the HS pulse. These findings reveal that even a short-term HS pulse can reset circadian rhythms and cause the HSF1-BMAL1:CLOCK interaction, suggesting the pivotal role of crosstalk between the mammalian circadian and HSR systems.