Effects of immersion in water containing high concentrations of CO2 (CO2-water) at thermoneutral on thermoregulation and heart rate variability in humans

Precooling via immersion in CO2-enriched water at 25°C decreased core body temperature but did not improve 10-km cycling time trial in the heat

This study compared the effects of precooling via whole-body immersion in 25°C CO2-enriched water (CO2WI), 25°C unenriched water (WI) or no cooling (CON) on 10-km cycling time trial (TT) performance. After 30 min of precooling (CO2WI, CON, WI) in a randomized, crossover manner, 11 male cyclists/triathletes completed 30-min submaximal cycling (65%VO2peak), followed by 10-km TT in the heat (35°C, 65% relative humidity). Average power output and performance time during TT were similar between conditions (p = 0.387 to 0.833). Decreases in core temperature (Tcore) were greater in CO2WI (-0.54 ± 0.25°C) than in CON (-0.32 ± 0.09°C) and WI (-0.29 ± 0.20°C, p = 0.011 to 0.022). Lower Tcore in CO2WI versus CON was observed at 15th min of exercise (p = 0.050). Skin temperature was lower in CO2WI and WI than in CON during the exercise (p < 0.001 to 0.031). Only CO2WI (1029 ± 305 mL) decreased whole-body sweat loss compared with CON (1304 ± 246 mL, p = 0.029). Muscle oxygenation by near-infrared spectroscopy (NIRS), thermal sensation, and thermal comfort were lower in CO2WI and WI versus CON only during precooling (p < 0.001 to 0.041). NIRS-derived blood volume was significantly lower in CO2WI and WI versus CON during exercise (p < 0.001 to 0.022). Heart rate (p = 0.998) and rating of perceived exertion (p = 0.924) did not differ between conditions throughout the experiment. These results suggested that CO2WI maybe more effective than WI for enhanced core body cooling and minimized sweat losses.

Carbon dioxide-induced decrease in extracellular pH enhances the production of extracellular matrix components by upregulating TGF-β1 expression via CREB activation in human dermal fibroblasts

Mild acidification caused by transcutaneous administration of carbon dioxide (CO2 ) has been reported to improve some epidermal skin impairments, such as desquamation and inflammation; however, its effects on dermal tissue remain unclear. Here, we examined the effect and mechanism of mild acidity on extracellular matrix (ECM) protein production in normal human dermal fibroblasts (NHDFs). To achieve this, the skin permeability of CO2 and its effect on intradermal pH were evaluated by treating reconstructed human skin equivalents (HSEs) with a CO2 -containing formulation. Additionally, NHDFs were cultured in a pH-adjusted medium (pH 6.5). CO2 successfully permeated HSEs and reduced the intradermal pH. Decreased extracellular pH activated CREB, upregulated TGF-β1 expression, promoted the production of elastic and collagen fibres, and increased hyaluronan concentration in NHDFs. Additionally, the low pH-induced increase in TGF-β1 expression was attenuated via the RNAi-mediated suppression of the expression of CREB1 and proton-sensing G protein-coupled receptors (GPCRs), including GPR4 and GPR65. Moreover, low pH-induced CREB activation was suppressed by the inhibition of the cAMP/PKA and PLC/PKC signalling pathways. Taken together, a CO2 -induced decrease in intradermal pH may promote ECM production in NHDFs via the upregulation of TGF-β1 expression, which was mediated by the activation of the GPCR signalling pathway and CREB, indicating that CO2 could be used to treat ultraviolet radiation-induced photoaging, intrinsic ageing and ECM deterioration.

Cardiovascular physiological effects of balneotherapy: focused on seasonal differences

Hot water bathing has been demonstrated to be an effective way to improve people's cardiovascular health in many studies. This study focused on seasonal physiological changes to provide suggestions on bathing methods based on season for hot spring bathing. Volunteers were recruited to the program of hot spring bathing at 38-40 °C in New Taipei City. Cardiovascular function, blood oxygen, and ear temperature were observed. There were five assessments for each participant during the study process: baseline, bathing for 20 min and 2 cycles *20 (2*20) min, resting for 20 min and 2*20 min after bathing, respectively. Lower blood pressure (p < 0.001), pulse pressure (p < 0.001), left ventricular dP/dt Max (p < 0.001), and cardiac output (p < 0.05) were identified after bathing then rested for 2*20 min in four seasons, compared to baseline by paired T test. However, in multivariate linear regression model, potential risk for bathing in summer was assumed by higher heart rate (+28.4%, p < 0.001), cardiac output (+54.9%, p < 0.001) and left ventricular dP/dt Max (+27.6%, p < 0.05) during bathing at 2*20 min in summer. Potential risk for bathing in winter was postulated by blood pressure lowering (cSBP -10.0%; cDBP -22.1%, p < 0.001) during bathing at 2*20 min in winter. Hot spring bathing is shown to potentially improve cardiovascular function via reducing cardiac workload and vasodilation effects. Prolonged hot spring bathing in summer is not suggested due to significantly increased cardiac stress. In winter, prominent drop of blood pressure should be concerned. We demonstrated the study enrollment, the hot-spring contents and location, and physiological changes of general trends or seasonal variations, which may indicate potential benefits and risks during and after bathing. (Abbreviations: BP, blood pressure; PP, pulse pressure; LV, left ventricular; CO, cardiac output; HR, heart rate; cSBP, central systolic blood pressure; cDBP, central diastolic blood pressure).

A preliminary investigation of the impact of artificially carbonated water bathing on canine skin physiological and barrier function

BACKGROUND

The effect of carbon dioxide (CO₂ )-rich water bathing on the skin has been studied extensively in humans. However, there have been few studies evaluating the impact of CO₂ -rich water bathing on canine skin physiology and barrier functions.

OBJECTIVES

To evaluate the impact of artificially carbonated water (ACW) bathing on skin parameters in healthy beagles.

ANIMALS

Six healthy beagles with no history of skin disease.

MATERIALS AND METHODS

Body temperature, skin temperature, transepidermal water loss (TEWL), skin hydration and skin blood flow were evaluated before and after single ACW bathing (37°C, 20 min) with a CO₂ concentration of >1000 ppm.

RESULTS

After ACW bathing, skin blood flow significantly increased (p < 0.0001), yet there were no significant changes in body temperature (p = 0.3124), skin temperature (p = 0.4911), TEWL (p = 0.5167) or skin hydration (p = 0.3084). There were no adverse events during the trials.

CONCLUSIONS AND CLINICAL IMPORTANCE

Artificially carbonated water water bathing could potentially increase skin blood flow without affecting skin temperature, body temperature and skin barrier function in dogs, similar to its effects in humans.

Thermoregulation and thermal sensation during whole-body water immersion at different water temperatures in healthy individuals: A scoping review

BACKGROUND

Severe thermal discomfort may increase risk of drowning due to hypothermia or hyperthermia from prolonged exposure to noxious water temperatures. The importance of using a behavioral thermoregulation model with thermal sensation may predict the thermal load that the human body receives when exposed to various immersive water conditions. However, there is no thermal sensation "gold standard" model specific for water immersion. This scoping review aims to present a comprehensive overview regarding human physiological and behavioral thermoregulation during whole-body water immersion and explore the feasibility for an accepted defined sensation scale for cold and hot water immersion.

METHODS

A standard literary search was performed on PubMed, Google Scholar, and SCOPUS. The words "Water Immersion," "Thermoregulation," "Cardiovascular responses" were used either as independent searched terms and MeSH terms (Medical Subject Headings) or in combination with other text words. The inclusion criteria for clinical trials terms to thermoregulatory measurements (core or skin temperature), whole-body immersion, 18-60 years old and healthy individuals. The prementioned data were analyzed narratively to achieve the overall study objective.

RESULTS

Twenty-three published articles fulfilled the review inclusion/exclusion criteria (with nine measured behavioral responses). Our outcomes illustrated a homogenous thermal sensation in a variety of water temperatures ranges, that was strongly associated with thermal balance, and observed different thermoregulatory responses. This scoping review highlights the impact of water immersion duration on human thermoneutral zone, thermal comfort zone, and thermal sensation.

CONCLUSION

Our findings enlighten the significance of thermal sensation as a health indicator for establishing a behavioral thermal model applicable for water immersion. This scoping review provides insight for the needed development of subjective thermal model of thermal sensation in relation to human thermal physiology specific to immersive water temperature ranges within and outside the thermal neutral and comfort zone.

Comparison of low-concentration carbon dioxide-enriched and tap water immersion on body temperature after passive heating

Background

Because carbon dioxide (CO₂)-enriched water causes cutaneous vasodilation, immersion in CO₂-enriched water facilitates heat transfer from the body to the water or from the water to the body. Consequently, immersion in CO₂-enriched water raises or reduces body temperature faster than immersion in fresh water. However, it takes time to dissolve CO₂ in tap water and because the dissolved CO₂ concentration decreases over time, the actual CO₂ concentration is likely lower than the stated target concentration. However, it is unclear whether water containing a lower CO₂ concentration would also cool the body faster than fresh water after body temperature had been increased.

Methods

Ten healthy males (mean age = 20 ± 1 years) participated in the study. Participants were first immersed for 15 min in a tap water bath at 40 °C to raise body temperature. They then moved to a tap water or CO₂-enriched water bath at 30 °C to reduce body temperature. The CO₂ concentration was set at 500 ppm. The present study measured cooling time and cooling rate (slope of the regression line relating auditory canal temperature (T_ac) to cooling time) to assess the cooling effect of CO₂-enriched water immersion.

Results

Immersion in 40 °C tap water caused T_ac to rise 0.64 ± 0.25 °C in the tap water session and 0.62 ± 0.27 °C in the CO₂-enriched water session (P > 0.05). During the 30 °C water immersion, T_ac declined to the baseline within 13 ± 6 min in tap water and 10 ± 6 min in CO₂-enriched water (P > 0.05). Cooling rates were 0.08 ± 0.06 °C/min in tap water and 0.08 ± 0.04 °C/min in CO₂-enriched water (P > 0.05).

Conclusions

CO₂-enriched water containing 500 ppm CO₂ did not cool faster than tap water immersion. This suggests that when the water temperature is 30 °C, a CO₂ concentration of 500 ppm is insufficient to obtain the advantageous cooling effect during water immersion after body temperature has been increased.

Clinical efficacy of artificially carbonated water bathing on superficial bacterial folliculitis in dogs

BACKGROUND

Bathing with artificially carbonated water is reported to be a valuable therapeutic option for various human skin disorders.

OBJECTIVE

To evaluate the clinical efficacy of artificially carbonated water bathing on superficial bacterial folliculitis (SBF) caused by Staphylococcus pseudintermedius (SP) in dogs.

ANIMALS

Nineteen dogs with SBF from whom SP was isolated from skin lesions were enrolled.

METHODS AND MATERIALS

Dogs with SBF were allocated randomly to either the artificially carbonated water bathing group or the control group bathed with tap water. The dogs were bathed with the designated water type on day (D)0, D7 and D14. Clinical scores and skin surface pH were evaluated on D0 and D21. Colony forming unit (cfu) assays were performed in vitro to investigate whether the artificially carbonated water affected growth of clinical SP isolates.

RESULTS

The mean rate of improvement in the clinical scores was significantly higher in the carbonated water group than in the control group. Dogs bathed with carbonated water exhibited significant decreases in their skin surface pH after bathing; dogs bathed with tap water did not. No dogs experienced significant adverse events. The cfus of SP incubated in vitro with artificially carbonated water did not significantly differ from those incubated with tap water.

CONCLUSION

Bathing with artificially carbonated water might be an effective and safe adjunctive therapy for canine SP-induced SBF.

Italian and Japanese public attention toward balneotherapy in the COVID-19 era

Italian and Japanese public widely use balneotherapy. The population interest in balneotherapy in coronavirus disease-2019 (COVID-19) era should be investigated. Therefore, we aimed to exploit Google Trends analysis, as a measure of peoples' interest in balneotherapy, in two countries, Italy and Japan. In this infodemiology study, Google Trends was queried for the lay terms widely used by the Italian population to refer to the balneotherapy setting (terme + termale) and by the Japanese to refer to the bathing place and balneotherapy facilities ( + スパ). The internet searches in 2020 were compared to overlapping time spans in 2016-2019 and were correlated with new confirmed cases/deaths. This study demonstrated that from February 23 to June 20, 2020, and from October 4 to December 26, 2020, the internet searches of the Italian words corresponding to balneotherapy were statistically significantly decreased; however, the internet searches were not significantly different in June 21 to October 3, 2020, compared to overlapping time spans in 2016-2019 in Italy. The study also showed that from March 15 to September 5, 2020, and from November 29 to December 26, 2020, the internet searches of the Japanese words corresponding to balneotherapy were statistically significantly decreased; however, the internet searches were significantly increased in September 13 to November 7, 2020, and were not significantly different in November 8 to 28, 2020, compared to overlapping time spans in 2016-2019 in Japan. There were significant negative correlations between the relative search volume and number of new cases (rho=-0.634; p<0.001)/deaths (rho=-0.856; p<0.001) in Italy and the number of new deaths (rho=-0.348; p=0.012) in Japan. Population interest in balneotherapy has changed in the COVID-19 era both in Italy and Japan. During the early stage of pandemic (March to June), the interest was lower. After this early stage, the interest showed a recovery in both countries. In Italy, the population interest reached to its prior levels in late June through early October, with a peak in August. In Japan, the recovery exceeded the prior 4-year levels in mid-September through early November. Then, both countries demonstrated a decline in interest: began in early October in Italy and late November in Japan. This information would allow us to understand/address the population response in the pandemic in respect of the balneotherapy and would guide the preparedness of healthcare providers and planners both in this pandemic and future similar situations.

A novel cooling method using carbon dioxide-rich water after passive heating

In the event of a marked rise in body temperature, it is often necessary to reduce the temperature quickly. One method to rapidly drop body temperature is cold water immersion. Because carbon dioxide (CO₂)-rich water causes cutaneous vasodilation, it may be that CO₂-rich water reduces body temperature faster than fresh water. To test that idea, I compared the effects of CO₂-rich and tap water immersion on auditory canal temperature (T_ac) after passive heating. Nine healthy male subjects participated in the study. Subjects were first immersed for 15 min in a tap water bath at 40 °C to raise body temperature. They then moved to a tap water or CO₂-rich water bath at 30 °C to reduce body temperature. Immersion in 40 °C tap water caused T_ac to rise 0.64 ± 0.11 °C in the tap water session and 0.71 ± 0.25 °C in the CO₂-rich water session (P > 0.05). During the 30 °C water immersion, T_ac declined and was significantly lower in CO₂-rich water than in tap water. Cooling rates were 0.06 ± 0.04 °C/min in tap water and 0.11 ± 0.05 °C/min in CO₂-rich water (P < 0.05). In addition, both thermal sensation (3.2 ± 1.0 vs. 2.1 ± 0.9; P < 0.01) and thermal comfort (1.2 ± 0.4 vs. 2.1 ± 0.8; P < 0.01) were significantly better in CO₂-rich water than tap water. These results suggest that CO₂-rich water immersion reduces T_ac 1.7 times faster than tap water immersion, and that CO₂-rich water immersion cools the body more comfortably than tap water immersion.

The effect of transcutaneous application of gaseous CO2 on diabetic chronic wound healing-A double-blind randomized clinical trial

Chronic wounds in diabetics are difficult to treat, therefore, adjuvant therapies have been investigated. Bathing in CO₂ -rich water (spa therapy) has been known in Europe for decades for its positive effect on peripheral vascular disorders. Recently, much effort has been invested in developing optimal application methods of CO₂ . Uses include subcutaneous injections of CO₂ , bathing in CO₂ -enriched water, and transcutaneous application of CO₂ . To verify the effect of transcutaneous application of gaseous CO₂ on the healing of chronic diabetic wounds, a randomized double-blind clinical research was designed. The research included 30 and 27 wounds in the study and control groups, respectively. In addition to standard treatment, patients in the study group received 20 therapies with medical-grade CO₂ gas and the control group received the same treatment with air. Results showed significantly faster healing in the study group: 20 of the 30 wounds in the study group were healed compared with none in the control group. Mean wound surface and volume in the study group was reduced significantly (surface: 96%, P = .001, volume: 99%, P = .003) compared with a small reduction in the control group (surface: 25%, P = .383, volume: 27%, P = .178). Considering our results, transcutaneous application of gaseous CO₂ is an effective adjuvant therapy in diabetic chronic wound treatment.

Temperature-dependent effects on CO2 water bath therapy induced changes in blood flow and vascularity in hind limb ischemia

To test if magnitudes of the beneficial actions of CO₂ water bath therapy on blood flow and vascular density are dependent upon temperature, ischemia in the hind limb of rats was induced by occluding the left femoral artery for 2 weeks and the animals were exposed to water bath therapy with or without CO₂ at 34 or 41 °C for 4 weeks (20 min treatment each day for 5 days/week). CO₂ water bath therapy at 34 °C increased peak, minimal, and mean blood flow by 190%-600% in the ischemic limb. On the other hand, CO₂ water bath treatment at 41 °C increased these parameters of blood flow by 37%, 55%, and 41%, respectively, in the ischemic limb. The small blood vessel count, an index of vascular density, in the ischemic limb was increased by CO₂ water bath therapy at 34 and 41 °C by 32% and 122%, respectively. No changes in the ischemic animals by CO₂ water bath therapy at 34 or 41 °C were observed in the heart rate, R-R interval, and plasma lipid or glucose levels. These data indicate that the beneficial effect of CO₂ water bath therapy at 34 °C on blood flow in the ischemic muscle is greater whereas that on vascular density is smaller than changes in these parameters at 41 °C.

Facial application of high-concentration carbon dioxide prevents epidermal impairment associated with environmental changes

Purpose

The transdermal application of carbon dioxide (CO₂) gas dissolved in a solution and bathing in carbonated springs have been known to improve circulatory disorders. We aimed to elucidate and profile the effects of CO₂ application on local skin function.

Patients and methods

A liquid formulation that included high-concentration CO₂ or a control formulation was applied to the face of healthy men for 8 weeks. Quantitative analysis was performed during the dry winter months.

Results

At the site where the control formulation was applied, transepidermal water loss (TEWL) increased while the moisturizing function (conductance) of facial skin decreased during the study period. However, at the CO₂-treated site, increases in TEWL and decreases in conductance were significantly suppressed. In addition, the deterioration in scaliness and wrinkles parameters were suppressed by ≥40% at the CO₂-treated site. There were no significant differences in skin surface pH or color properties between the control and test sites.

Conclusion

This study suggests that the continuous application of a high-concentration CO₂ formulation can affect skin physiology and has the potential to suppress reductions in the barrier and moisturizing functions of the stratum corneum accompanied by desquamation, which occurs during the winter.

Effects of CO2 water-bath treatment on blood flow and angiogenesis in ischemic hind limb of diabetic rat

The effects of CO₂ water-bath therapy on the hind limb of diabetic animals with or without peripheral ischemia were examined. Diabetes was induced in rats by administering streptozotocin (65 mg·kg^-1), and the animals were then divided into 3 groups. After 4 weeks, peripheral ischemia was induced by ligation of the femoral artery for 2 weeks in 2 groups (diabetic ischemic) of diabetic rats, whereas the femoral artery was not occluded in the third group (diabetic). All these animals were subjected to water-bath therapy (with or without CO₂ mixing; 20 min·day^-1 for 5 days·week^-1) for a period of 4 weeks. Both peak and mean flows, unlike minimal flow, in diabetic ischemic limbs were increased about a twofold by CO₂ water-bath treatment. Morphological examination of hind limb tissue sections revealed about a twofold increase in the small artery count in diabetic ischemic animals upon CO₂ water-bath treatment. These results indicate that CO₂ water-bath therapy augments the blood flow and development of angiogenesis in the skeletal muscle of diabetic ischemic animals and thus may be of some benefit for the treatment of peripheral arterial disease in diabetes.

How does spa treatment affect cardiovascular function and vascular endothelium in patients with generalized osteoarthritis? A pilot study through plasma asymmetric di-methyl arginine (ADMA) and L-arginine/ADMA ratio

The study aims to investigate the effect of spa treatment on vascular endothelium and clinical symptoms of generalized osteoarthritis. Forty generalized osteoarthritis (GOA) patients referred to a government spa hospital, and 40 GOA patients followed on university hospital locomotor system disease ambulatory clinics were included as study and control groups, respectively. Study group received spa treatment including thermal water baths, physical therapy modalities, and exercises. Control group was followed with home exercises for 15 days. Plasma ADMA, L-arginine, L-arginine/ADMA ratio, routine blood analyses, 6-min walking test, including fingertip O₂ saturation, systolic/diastolic blood pressure, and pulse rate, were measured at the beginning and at the end of treatment. Groups were evaluated with VAS pain, patient, and physician global assessment; HAQ; and WOMAC at the beginning, at the end, and after 1 month of treatment. In study group, L-arginine and L-arginine/ADMA ratio showed statistically significant increase after treatment. Plasma ADMA levels did not change. There is no significant difference in intergroup comparison. Study group displayed statistically significant improvements in all clinical parameters. The study showed that spa treatment does not cause any harm to the vascular endothelium through ADMA. Significant increase in plasma L-arginine and L-arginine/ADMA ratio suggests that balneotherapy may play a preventive role on cardiovascular diseases. Balneotherapy provides meaningful improvements on clinical parameters of GOA.

Carbon dioxide water-bath treatment augments peripheral blood flow through the development of angiogenesis

In this study, we investigated the effects of CO₂ water-bath therapy on blood flow and angiogenesis in the ischemic hind limb, as well as some plasma angiogenic factors in peripheral ischemic model. The hind limb ischemia was induced by occluding the femoral artery for 2 weeks in rats and treated with or without CO₂ water-bath therapy at 37 °C for 4 weeks (20 min treatment every day for 5 days per week). The peak blood flow and minimal and mean blood flow in the ischemic skeletal muscle were markedly increased by the CO₂ water-bath therapy. This increase in blood flow was associated with development of angiogenesis in the muscle, as well as reduction in the ischemia-induced increase in plasma malondialdehyde levels. Although plasma vascular endothelial growth factor and nitric oxide levels were increased in animals with peripheral ischemia, the changes in these biomarkers were not affected by CO₂ water-bath therapy. These results suggest that augmentation of blood flow in the ischemic hind limb by CO₂ water-bath therapy may be due to the development of angiogenesis and reduction in oxidative stress.

Effect of spa therapy with saline balneotherapy on oxidant/antioxidant status in patients with rheumatoid arthritis: a single-blind randomized controlled trial

Oxidative stress has been shown to play a contributory role in the pathogenesis of rheumatoid arthritis (RA). Recent studies have provided evidence for antioxidant properties of spa therapy. The purpose of this study is to investigate whether spa therapy with saline balneotherapy has any influence on the oxidant/antioxidant status in patients with RA and to assess clinical effects of spa therapy. In this investigator-blind randomized controlled trial, we randomly assigned 50 patients in a 1:1 ratio to spa therapy plus standard drug treatment (spa group) or standard drug treatment alone (control group). Spa group followed a 2-week course of spa therapy regimen consisting of a total of 12 balneotherapy sessions in a thermal mineral water pool at 36-37 °C for 20 min every day except Sunday. All clinical and biochemical parameters were assessed at baseline and after spa therapy (2 weeks). The clinical parameters were pain intensity, patient global assessment, physician global assessment, Health Assessment Questionnaire disability index (HAQ-DI), Disease Activity Score for 28-joints based on erythrocyte sedimentation rate (DAS28-4[ESR]). Oxidative status parameters were malondialdehyde (MDA), nonenzymatic superoxide radical scavenger activity (NSSA), antioxidant potential (AOP), and superoxide dismutase (SOD). The NSSA levels were increased significantly in the spa group (p = 0.003) but not in the control group (p = 0.509); and there was a trend in favor of spa therapy for improvements in NSSA levels compared to control (p = 0.091). Significant clinical improvement was found in the spa group compared to the control in terms of patient global assessment (p = 0.011), physician global assessment (p = 0.043), function (HAQ-DI) (p = 0.037), disease activity (DAS28-4[ESR]) (0.044) and swollen joint count (0.009), and a trend toward improvement in pain scores (0.057). Spa therapy with saline balneotherapy exerts antioxidant effect in patients with RA as reflected by the increase in NSSA levels after spa therapy; whether this antioxidant effect contributes to the clinical improvements observed remains to be verified.

Physiological and Psychological Effects of Viewing a Kiwifruit (Actinidia deliciosa 'Hayward') Orchard Landscape in Summer in Japan

The physiological and psychological relaxation effects of viewing a kiwifruit (Actinidia deliciosa ‘Hayward’) orchard landscape were investigated. Seventeen Japanese adult females (46.1 ± 8.2 years) viewed a kiwifruit orchard landscape or a building site (control) for 10 min. The heart rate variability and heart rate were determined. The modified semantic differential method and the short-form Profile of Mood States were used to assess the psychological effects. Compared with viewing the building site, viewing the kiwifruit orchard landscape resulted in a significant increase in the parasympathetic activity, a marginally significant decrease in the heart rate, a significant increase in “comfortable”, “relaxed” and “natural” feelings and a significant improvement in mood states.

Scientific evidence-based effects of hydrotherapy on various systems of the body

The use of water for various treatments (hydrotherapy) is probably as old as mankind. Hydrotherapy is one of the basic methods of treatment widely used in the system of natural medicine, which is also called as water therapy, aquatic therapy, pool therapy, and balneotherapy. Use of water in various forms and in various temperatures can produce different effects on different system of the body. Many studies/reviews reported the effects of hydrotherapy only on very few systems and there is lack of studies/reviews in reporting the evidence-based effects of hydrotherapy on various systems. We performed PubMed and PubMed central search to review relevant articles in English literature based on "effects of hydrotherapy/balneotherapy" on various systems of the body. Based on the available literature this review suggests that the hydrotherapy has a scientific evidence-based effect on various systems of the body.

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.

Carbon dioxide balneotherapy and cardiovascular disease

Carbon dioxide (CO(2)) balneotherapy is a kind of remedy with a wide spectrum of applications which have been used since the Middle Ages. However, its potential use as an adjuvant therapeutic option in patients with cardiovascular disease is not yet fully clarified. We performed a thorough review of MEDLINE Database, EMBASE, ISI WEB of Knowledge, COCHRANE database and sites funded by balneotherapy centers across Europe in order to recognize relevant studies and aggregate evidence supporting the use of CO(2) baths in various cardiovascular diseases. The three main effects of CO(2) hydrotherapy during whole body or partial immersion, including decline in core temperature, an increase in cutaneous blood flow, and an elevation of the score on thermal sensation, are analyzed on a pathophysiology basis. Additionally, the indications and contra-indications of the method are presented in an evidence-based way, while the need for new methodologically sufficient studies examining the use of CO(2) baths in other cardiovascular substrates is discussed.

Crenotherapy: a neglected resource for human health now re-emerging on sound scientific concepts

Recent mechanistic evidence demonstrates that spa-based therapy (or, as we propose, crenotherapy from the Greek word kapparhoepsilonnueta, spring fountain) is indeed based on solid scientific data. This mini-review highlights the latest insights into the mechanisms of crenotherapy derived from in vitro experiments, studies on animal models, and carefully designed clinical trials. Although more basic and clinical data are still needed, crenotherapy is coming of age as a modern, scientifically sound therapy. As the underlying mechanisms are uncovered, it is becoming possible to choose the most appropriate applications of this centuries-old practice, possibly reducing medical costs, thus explaining the current worldwide renewed interest in crenotherapy.