Leg heating using far infra-red radiation in patients with chronic heart failure acutely improves the hemodynamics, vascular endothelial function, and oxidative stress

The multifaceted benefits of passive heat therapies for extending the healthspan: A comprehensive review with a focus on Finnish sauna

Passive heat therapy is characterized by exposure to a high environmental temperature for a brief period. There are several types of passive heat therapy which include hot tubs, Waon therapy, hydrotherapy, sanarium, steam baths, infrared saunas and Finnish saunas. The most commonly used and widely studied till date are the Finnish saunas, which are characterized by high temperatures (ranging from 80-100°C) and dry air with relative humidity varying from 10-20%. The goal of this review is to provide a summary of the current evidence on the impact of passive heat therapies particularly Finnish saunas on various health outcomes, while acknowledging the potential of these therapies to contribute to the extension of healthspan, based on their demonstrated health benefits and disease prevention capabilities. The Finnish saunas have the most consistent and robust evidence regarding health benefits and they have been shown to decrease the risk of health outcomes such as hypertension, cardiovascular disease, thromboembolism, dementia, and respiratory conditions; may improve the severity of musculoskeletal disorders, COVID-19, headache and flu, while also improving mental well-being, sleep, and longevity. Finnish saunas may also augment the beneficial effects of other protective lifestyle factors such as physical activity. The beneficial effects of passive heat therapies may be linked to their anti-inflammatory, cytoprotective and anti-oxidant properties and synergistic effects on neuroendocrine, circulatory, cardiovascular and immune function. Passive heat therapies, notably Finnish saunas, are emerging as potentially powerful and holistic strategies to promoting health and extending the healthspan in all populations.

Advances in far-infrared research: therapeutic mechanisms of disease and application in cancer detection

Far infrared (FIR) irradiation is commonly used as a convenient, non-contact, non-invasive treatment for diseases such as myocardial ischemia, diabetes, and chronic kidney disease. In this review, we focus on reviewing the potential therapeutic mechanisms of FIR and its cutting-edge applications in cancer detection. Firstly, we searched the relevant literature in the last decade for systematic screening and briefly summarized the biophysical properties of FIR. We then focused on the possible mechanisms of FIR in wound healing, cardiovascular diseases, and other chronic diseases. In addition, we review recent applications of FIR in cancer detection, where Fourier transform infrared spectroscopy and infrared thermography provide additional diagnostic methods for the medical diagnosis of cancer. Finally, we conclude and look into the future development of FIR for disease treatment and cancer detection. As a high-frequency non-ionizing wave, FIR has the advantages of safety, convenience, and low cost. We hope that this review can provide biological information reference and relevant data support for those who are interested in FIR and related high-frequency non-ionizing waves, to promote the further application of FIR in the biomedical field.

Far-Infrared Ameliorates Pb-Induced Renal Toxicity via Voltage-Gated Calcium Channel-Mediated Calcium Influx

Far-infrared (FIR), characterized by its specific electromagnetic wavelengths, has emerged as an adjunctive therapeutic strategy for various diseases, particularly in ameliorating manifestations associated with renal disorders. Although FIR was confirmed to possess antioxidative and anti-inflammatory attributes, the intricate cellular mechanisms through which FIR mitigates lead (Pb)-induced nephrotoxicity remain enigmatic. In this study, we investigated the effects of FIR on Pb-induced renal damage using in vitro and in vivo approaches. NRK52E rat renal cells exposed to Pb were subsequently treated with ceramic-generated FIR within the 9~14 μm range. Inductively coupled plasma mass spectrometry (ICP-MS) enabled quantitative Pb concentration assessment, while proteomic profiling unraveled intricate cellular responses. In vivo investigations used Wistar rats chronically exposed to lead acetate (PbAc) at 6 g/L in their drinking water for 15 weeks, with or without a concurrent FIR intervention. Our findings showed that FIR upregulated the voltage-gated calcium channel, voltage-dependent L type, alpha 1D subunit (CaV1.3), and myristoylated alanine-rich C kinase substrate (MARCKS) (p < 0.05), resulting in increased calcium influx (p < 0.01), the promotion of mitochondrial activity, and heightened ATP production. Furthermore, the FIR intervention effectively suppressed ROS production, concurrently mitigating Pb-induced cellular death. Notably, rats subjected to FIR exhibited significantly reduced blood Pb levels (30 vs. 71 μg/mL; p < 0.01), attenuated Pb-induced glomerulosclerosis, and enhanced Pb excretion compared to the controls. Our findings suggest that FIR has the capacity to counteract Pb-induced nephrotoxicity by modulating calcium influx and optimizing mitochondrial function. Overall, our data support FIR as a novel therapeutic avenue for Pb toxicity in the kidneys.

Effects of a Graphene Heating Device on Fatigue Recovery of Biceps Brachii

Far-infrared (FIR) is considered to be an ideal method to promote fatigue recovery due to its high permeability and strong radiation. In this paper, we report a flexible and wearable graphene heating device to help fatigue recovery of human exercise by using its high FIR divergence property. This study compares two different fatigue recovery methods, graphene far-infrared heating device hot application and natural recovery, over a 20 min recovery time among the male colleges' exhaustion exercise. Experimental results show that the achieved graphene device holds excellent electro-thermal radiation conversion efficiency of 70% and normal total emissivity of 89%. Moreover, the graphene FIR therapy in our work is more energy-efficient, easy to use, and wearable than traditional fatigue recovery methods. Such an anti-fatigue strategy offers new opportunities for enlarging potential applications of graphene film in body science, athletic training recovery, and wearable devices.

Crossover trial of the effects of a far-infrared heater that heats the feet with ceramic balls on autonomic nervous activity and mood states

INTRODUCTION

The accumulation of fatigue and stress creates problems, including reductions in quality of life and productivity.

OBJECTIVES

To investigate the effects of a far-infrared heater that heats the feet with ceramic balls on autonomic nervous activity and mood states.

METHODS

This study was performed as a crossover trial. Participants comprised 20 women. On different days, each participant underwent 15 min of foot warming with the far-infrared heater (far-infrared group) or remained seated for 15 min (control group). Autonomic nervous activity (low-frequency component/high-frequency component, high-frequency) and mood states scales (Profile of Mood States Second Edition and Two-Dimensional Mood Scale for Self-monitoring and Self-regulation of Momentary Mood States) during the study intervention were measured and compared between groups.

RESULTS

Low-frequency/high-frequency was significantly higher in the control group 10 min after the start of intervention than at baseline (P = .033). Low-frequency/high-frequency was significantly lower in the far-infrared group than in the control group at 5 min (P = .027), 10 min (P = .011), and 15 min (P = .015). High-frequency was significantly higher in the far-infrared group at 5 min (P = .008), 10 min (P = .004), and 15 min (P = .015) than at baseline. High-frequency 5 min after the start of intervention was significantly higher in the far-infrared group than in the control group (P = .033). POMS2 scores improved significantly more in the far-infrared group than in the control group, including in fatigue-inertia (P = .019), tension-anxiety (P = .025), and total mood disturbance (P = .019). Finally, the far-infrared group showed greater improvements in Two-Dimensional Mood Scale-Short Term scores such as stability (P = .002) and pleasure (P = .013).

CONCLUSION

Using the far-infrared heater to heat the feet with ceramic balls stabilized and improved mood, reduced Fatigue-Inertia and Tension-Anxiety, and alleviated total mood disturbance. Parasympathetic nervous system activation was observed from 5 min after the start of heating, suggesting that short-duration heat stimulation of the feet is effective.

Relationship between body composition indices and changes in body temperature due to hot pack use

Background

Hot pack application is used to reduce pain and muscle stiffness at the treated site. However, the effects of hot pack application on the whole body have not been clarified. We investigated the relationship between body composition indices and the hot pack-induced increase in body temperature.

Methods

We recruited 17 healthy men (age, 22.0 ± 3.3 years) who participated in the study on five different days and applied “dry” hot packs at four different sites (the most frequently used sites): right shoulder, lower back, both popliteal areas, and lower back plus popliteal areas. The study protocol involved the measurement of body composition followed by 10 min of bed rest, 15 min of warming with a hot pack, and 20 min of subsequent rest. Heart rate and body temperature were measured continuously, and blood pressure was recorded at 5-min intervals. Body temperature was measured at the right upper arm, precordium, abdomen, lumbus, right hallux, right femur, and right auditory canal.

Results

Skin temperature increased significantly at and near the hot pack application site, but this finding showed no relationship with body composition indices. The warmability distal to the application site was negatively correlated with the body water content index. The auditory canal temperature did not change in any of the sessions.

Conclusions

Hot pack usage alone did not increase the deep-body temperature and only increased the temperature around the application area. Moreover, higher body water content may allow for easier dissipation of heat from the peripheral extremities.

Effect of Artificial Carbon Dioxide-Rich Water Immersion on Peripheral Blood Flow in Healthy Volunteers: Preliminary Study about Artificial Carbon Dioxide-Rich Water

BACKGROUND: Peripheral blood circulation disorder is one of the global health problems. Balneotherapy that uses CO2 springs may be one of the complementary treatment options. The device to produce artificial CO2-rich water is needed to achieve an improvement effect, at least almost like the improvement effect of natural balneotherapy. AIM: This study aims to investigate the effect of artificial CO2-rich water immersion on peripheral blood flow using Bicarbonated JesC CREA BC-2000. METHODS AND MATERIALS: Thirty-nine healthy volunteers participated in this study. Each subject immersed both of their legs in a mixed solution from water and CO2 at temperature 38°C. This solution was mixed using a device, namely, “Bicarbonated JesC CREA BC-2000”. Peripheral blood flow was measured for 5 min before immersion (in this study, we denoted it as the mean basal blood flow), 10 min during immersion, and 5 min after immersion using pocket JMS laser Doppler flowmetry MBF-IIA. Repeated analysis of variance was used for statistical analysis. RESULTS: There is the difference in peripheral blood flow among before, during, and after immersing the legs into artificial CO2-rich water using Bicarbonated JesC CREA BC-2000 (p < 0.001). CONCLUSION: Bicarbonated JesC CREA BC-2000 may be used as the device to produce an artificial CO2-rich water bath that may affect peripheral blood flow in healthy volunteers.

Acute Hemodynamic Improvement by Thermal Vasodilation inside the Abdominal and Iliac Arterial Segments of Young Sedentary Individuals

OBJECTIVE

To study the hemodynamic response to lower leg heating intervention (LLHI) inside the abdominal and iliac arterial segments (AIAS) of young sedentary individuals.

METHODS

A Doppler measurement of blood flow was conducted for 5 young sedentary adults with LLHI. Heating durations of 0, 20, and 40 min were considered. A lumped parameter model (LPM) was used to ascertain the hemodynamic mechanism. The hemodynamics were determined via numerical approaches.

RESULTS

Ultrasonography revealed that the blood flow waveform shifted upwards under LLHI; in particular, the mean flow increased significantly (p < 0.05) with increasing heating duration. The LPM showed that its mechanism depends on the reduction in afterload resistance, not on the inertia of blood flow and arterial compliance. The time-averaged wall shear stress, time-averaged production rate of nitric oxide, and helicity in the external iliac arteries increased more significantly than in other segments as the heating duration increased, while the oscillation shear index (OSI) and relative residence time (RRT) in the AIAS declined with increasing heating duration. There was a more obvious helicity response in the bilateral external iliac arteries than the OSI and RRT responses.

CONCLUSION

LLHI can effectively induce a positive hemodynamic environment in the AIAS of young sedentary individuals.

Can heat therapy help patients with heart failure?

To review and analyze the clinical outcomes of thermal therapy (≤1.4°C increase in core body temperature) in patients with heart failure (HF). A systematic review and meta-analysis regarding the effects of thermal therapy on HF was done by searching PubMed, Ovid Medline, Ovid Embase, Scopus, and internal databases up to date (2019). Improvement in the New York Heart Association (NYHA) class: Ten studies with 310 patients showed significant improvement in NYHA class. Only 7 among 40 patients remained in Class IV and 99 patients in Class III from 155 patients. Increased patients in lower classes indicate that more patients showed improvement. Sixteen studies on 506 patients showed an overall improvement of 4.4% of left ventricular ejection fraction (LVEF). Four studies reported improved endothelial dysfunction by 1.7% increase in flow-mediated dilation (FMD) on 130 patients. Reduction in blood pressure: Thermal therapy reduced both systolic blood pressure (SBP) and diastolic blood pressure by 3.1% and 5.31%, respectively, in 431 patients of 15 studies. Decrease in cardiothoracic ratio (CTR): Eight studies reported an average of 5.55% reduction of CTR in a total of 347 patients. Improvement in oxidative stress markers: Plasma brain natriuretic peptide (BNP) levels significantly decreased (mean difference of 14.8 pg/dL) in 303 patients of 9 studies. Improvement of quality of life: Among 65 patients, thermal therapy reduced cardiac death and rehospitalization by 31.3%. A slight increase in core body temperature is a promising, noninvasive, effective, and complementary therapy for patients with HF. Further clinical studies are recommended.

Accumulated nocturnal hypoxemia predict arterial endothelial function in patients with sleep-disordered breathing with or without chronic heart failure

ABTSRACT

Sleep-disordered breathing (SDB) is often accompanied with the chronic heart failure (CHF). Hypoxemia due to pulmonary congestion from CHF and concurrent SDB might synergistically impair endothelial function and worsen the prognosis. However, the main factors affecting deterioration of endothelial function are unknown and whether the influence of hypoxemia differs in SDB patients with and without CHF remains unclear. Fifty-three patients (CHF group, n = 23; non-CHF group, n = 30) underwent polysomnography to evaluate their SDB and flow-mediated vasodilation (FMD) measurements to assess arterial endothelial function. We examined the relationships between FMD and SDB-related parameters, including our original index of accumulated hypoxemia by SDB throughout one-night sleep: the time desaturation summation index (TDS), calculated as follows: (100% - averaged arterial oxygen saturation during sleep) × total sleep time. The mean age in the CHF and non-CHF groups was 59.0 ± 13.5 and 57.7 ± 11.4 years, respectively. Although the FMD in the 2 groups were not significantly different, well-known adverse factors for FMD such as serum lipid profiles, blood pressure levels, and conventional indices of SDB were worse in the non-CHF group. Only the TDS was not significantly different between 2 groups and associated with FMD as shown by the univariate analysis (CHF: p < 0.05, non-CHF: p < 0.01) and multivariate analysis (CHF: p < 0.05, non-CHF: p < 0.01). Accumulated hypoxemia (TDS) rather than the frequency of hypoxemia might more influence on the endothelial function irrespective of the cardiac state. Removal of accumulation of nocturnal hypoxemia might be a target for treatment equally in the patients with and without CHF.

Potential mechanisms for the effects of far-infrared on the cardiovascular system - a review

Far-infrared (FIR) is a form of thermal radiation, which may have beneficial effects on cardiovascular health. Clinical studies suggest that FIR irradiation may have therapeutic effects in heart failure, myocardial ischaemia and may improve flow and survival of arteriovenous fistula. Animal studies have suggested a wide range of potential mechanisms involving endothelial nitric oxide synthase and nitric oxide bioavailability, oxidative stress, heat shock proteins and endothelial precursor cells. However, the exact cellular and molecular mechanism of FIR on the cardiovascular system remains elusive. The purpose of this review is to discuss the current literature, focusing on mechanistic studies involving the cardiovascular system, and with a view to highlighting areas for future investigation.

The effect of far infrared radiation therapy on inflammation regulation in lipopolysaccharide-induced peritonitis in mice

Objective:

Far infrared radiation has been widely used in a variety of healthcare institutions and clinical research. Previous studies have shown that far infrared radiation can promote blood circulation and enhance the functioning of the immune system. Many patients receiving peritoneal dialysis have been co-treated with far infrared radiation to reduce the occurrence of inflammation. This study seeks to evaluate the effects of far infrared radiation therapy on inflammation.

Method:

We used the lipopolysaccharide-induced peritonitis mouse model to study the effect of far infrared radiation treatment. Sixteen mice were randomly divided into two groups, a far infrared radiation treatment group (n = 8) and a non-far infrared radiation treatment group (n = 8). Collected blood samples were studied by analyzing the RNA level of peripheral blood mononuclear cells and the plasma protein levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and endothelial nitric oxide synthase (eNOS).

Results:

The administration of far infrared radiation inhibited the RNA levels of interleukin-6 and TNF-α after stimulation by lipopolysaccharide. The far infrared radiation treatment inhibited the endothelial nitric oxide synthase RNA levels at 1 h, but the RNA levels returned close to the baseline level after 2 h. In the control group, the endothelial nitric oxide synthase RNA levels were continuously decreasing. The interleukin-6 concentration in the plasma of the far infrared radiation group showed significant inhibition 30 min after lipopolysaccharide stimulation. The tumor necrosis factor alpha RNA concentration in plasma of the far infrared radiation group was significantly reduced 2 h after lipopolysaccharide stimulation.

Conclusion:

Far infrared radiation therapy can inhibit interleukin-6 and tumor necrosis factor alpha RNA levels of peripheral blood mononuclear cells and recover endothelial nitric oxide synthase expression. These results demonstrate that far infrared radiation therapy might aid in reducing the level of inflammation experienced by patients going through peritoneal dialysis treatment.

Effect of leg immersion in mild warm carbonated water on skin and muscle blood flow

Leg immersion in carbonated water improves endothelial-mediated vasodilator function and decreases arterial stiffness but the mechanism underlying this effect remains poorly defined. We hypothesized that carbonated water immersion increases muscle blood flow. To test this hypothesis, 10 men (age 21 ± 0 years; mean ± SD) underwent lower leg immersion in tap or carbonated water at 38°C. We evaluated gastrocnemius muscle oxyhemoglobin concentration and tissue oxygenation index using near-infrared spectroscopy, skin blood flow by laser Doppler flowmetry, and popliteal artery (PA) blood flow by duplex ultrasound. Immersion in carbonated, but not tap water elevated PA (from 38 ± 14 to 83 ± 31 mL/min; P < 0.001) and skin blood flow (by 779 ± 312%, P < 0.001). In contrast, lower leg immersion elevated oxyhemoglobin concentration and tissue oxygenation index with no effect of carbonation (P = 0.529 and P = 0.495). In addition, the change in PA blood flow in response to immersion in carbonated water correlated with those of skin blood flow (P = 0.005) but not oxyhemoglobin concentration (P = 0.765) and tissue oxygenation index (P = 0.136) while no relations was found for tap water immersion. These findings indicate that water carbonation has minimal effect on muscle blood flow. Furthermore, PA blood flow increases in response to lower leg immersion in carbonated water likely due to a large increase in skin blood flow.

Analysis of muscular elasticity according to infrared and ultrasound therapy by sonoelastography

[Purpose] The purpose of this study was to evaluate the effect of physical therapy on elasticity of muscles quantitatively by using sonoelastography equipment in infrared and ultrasound treatment commonly used in hospital physical therapy rooms. [Participants and Methods] We also investigated correlations among various variables such as height, weight, BMI (Body Mass Index), body fat mass, muscle mass, and basal metabolic rate. From July 30th 2017 to August 30th, 2017, muscular elasticity ratio was measured in 10 males in their 20s by comparing muscles of the upper and lower extremities before and after ultrasound and infrared therapy. [Results] Results showed that muscular elasticity was increased 1.55 ± 0.41 folds in forearm muscle region of the upper extremity in ultrasound therapy, which was significantly higher than the increase (1.23 ± 0.10 folds) in infrared therapy. Thus, ultrasound therapy and infrared therapy both would have good result in cardiac treatment for 1-cm away region. In ultrasound therapy and infrared therapy, elasticity increase rates in forearm region of the upper extremity were higher when body fat mass and BMI were increased. [Conclusion] Results of this study could be used as basic data for ultrasound and infrared therapy studies in the future.

Acute vascular effects of carbonated warm water lower leg immersion in healthy young adults

Endothelial dysfunction is associated with increased cardiovascular mortality and morbidity; however, this dysfunction may be ameliorated by several therapies. For example, it has been reported that heat‐induced increases in blood flow and shear stress enhance endothelium‐mediated vasodilator function. Under these backgrounds, we expect that carbon dioxide (CO₂)‐rich water‐induced increase in skin blood flow improves endothelium‐mediated vasodilation with less heat stress. To test our hypothesis, we measured flow‐mediated dilation (FMD) before and after acute immersion of the lower legs and feet in mild warm (38°C) normal or CO₂‐rich tap water (1000 ppm) for 20 min in 12 subjects. Acute immersion of the lower legs and feet in mild warm CO₂‐rich water increased FMD (P < 0.01) despite the lack of change in this parameter upon mild warm normal water immersion. In addition, FMD was positively correlated with change in skin blood flow regardless of conditions (P < 0.01), indicating that an increase in skin blood flow improves endothelial‐mediated vasodilator function. Importantly, the temperature of normal tap water must reach approximately 43°C to achieve the same skin blood flow level as that obtained during mild warm CO₂‐rich water immersion (38°C). These findings suggest that CO₂‐rich water‐induced large increases in skin blood flow may improve endothelial‐mediated vasodilator function while causing less heat stress.

The relationship between advanced glycation end products and ocular circulation in type 2 diabetes

AIMS

To determine whether skin autofluorescence (SAF) and serum pentosidine, biomarkers of advanced glycation end products (AGEs), were associated with ocular microcirculation in type 2 diabetes patients with early diabetic retinopathy (DR).

METHODS

This study included 46 eyes of 46 type 2 diabetes patients with no DR or non-proliferative DR. SAF was measured with an autofluorescence reader. Optic nerve head (ONH) microcirculation, represented by mean blur rate (MBR), was measured with laser speckle flowgraphy. Overall MBR, vascular MBR, and tissue MBR were calculated in software. MBR, SAF, pentosidine levels, and clinical findings, including central macular thickness (CMT), were then compared.

RESULTS

SAF in the diabetes patients was correlated with age (P=0.018). Serum pentosidine was correlated with age, vascular MBR and tissue MBR (P=0.046, P=0.035, and P=0.01, respectively). CMT was correlated with tissue MBR (P=0.016), but not with vascular MBR or overall MBR. Separate multiple regression analyses of independent contributing factors revealed that age, SAF, serum pentosidine, duration of diabetes, and pulse rate contributed to tissue MBR (P=0.041, P=0.046, P=0.022, P=0.011 and P=0.036, respectively), while SAF, HbA1c, pulse rate, tissue MBR, diastolic blood pressure, and creatinine contributed to CMT (P=0.005, P=0.039, P<0.001, P<0.001, P=0.022 and P=0.001, respectively).

CONCLUSIONS

Tissue MBR may be closely related to AGE levels and CMT in type 2 diabetes patients with early DR, suggesting that ocular circulation might be potential early biomarkers of DR.

Effects of far infrared rays emitting clothing on recovery after an intense plyometric exercise bout applied to elite soccer players: a randomized double-blind placebo-controlled trial

The aim was to investigate the effects of far infrared (FIR) ray emitting clothes on indirect markers of exercise-induced muscle damage and physical performance recovery after a plyometric bout applied to soccer players. Twenty-one male players (18.9±0.6 years; 70.8±5.01 kg; 178.3±0.06 cm) performed 100 drop-jumps. Six hours after the bout, athletes put on FIR clothes (FIR) (density of 225 g·m^-2, 88% far infrared rays emitting polyamide 66 Emana yarn (PA66) fibre, 12% Spandex, emissivity of 0.88 and power emitted of 341 W/m2µm at 37°C in the 5-20 µm wavelength range, patent WO 2009/077834 A2) (N = 10) or placebo clothes (PLA) (N = 11). Mid-thigh circumferences, creatine kinase (CK), and delayed-onset muscle soreness (DOMS) were assessed before, immediately after and 24, 48, and 72 h after the bout. Squat (SJ) and countermovement jump (CMJ) heights were measured before and at 24, 48, and 72 h after, while 1RM leg press (maximum strength) was measured before and at 72 h after the plyometrics. No differences between groups were found in mid-thigh circumferences, SJ, CMJ or 1RM. CK increased significantly 24 h after the plyometrics in comparison to before (p < 0.05) in both groups. PLA showed significant DOMS increases at 24, 48, and 72 h, while FIR showed significant increases at 24 and 48 h (p < 0.05). DOMS effect sizes were greater in FIR (moderate at 48 h, ES = 0.737 and large at 72 h, ES = 0.844), suggesting that FIR clothes may reduce perceived DOMS after an intense plyometric session performed by soccer players.

Cumulative Hypoxemia During Sleep Predicts Vascular Endothelial Dysfunction in Patients With Sleep-Disordered Breathing

BACKGROUND

Sleep-disordered breathing (SDB) is associated with repeated intermittent hypoxemia, and it is known as one of the risk factors for cardiovascular diseases. Previous studies assessing the effects of frequency and depth of hypoxemia on cardiovascular diseases have shown conflicting results. The aim of the current study was to clarify what SDB-related parameters most predict endothelial dysfunction to better understand the pathogenesis of endothelial dysfunction in patients with SDB.

METHODS

We conducted polysomnography (PSG) and measured flow-mediated vasodilation response (%FMD) in 50 outpatients suspected of SDB. Evaluated indices included: apnea-hypopnea index (AHI), 3% oxygen desaturation index (3%ODI), averaged arterial oxygen saturation (averaged SpO2), lowest arterial oxygen saturation (lowest SpO2), ratio of arterial oxygen saturation <90% (

RESULTS

Significant differences were observed only in the TDS between the first and third (P = 0.03) and between the first and forth (P = 0.04) quartile groups, stratified by %FMD. The %FMD showed a significant relationship with TDS (β = -0.47, P = 0.001), even after adjusting for confounding factors (β = -0.33, P = 0.02). In contrast, AHI, 3%ODI, averaged SpO2, lowest SpO2, and

CONCLUSIONS

This study shows the validity of TDS in predicting endothelial damage in patients with SDB. Cumulative hypoxemia, rather than the frequency of hypoxemic events presented as AHI, may be a greater contributing factor in causing endothelial dysfunction. A simple index like TDS may be a useful and novel indicator of the influence of SDB on the vasculature.

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Key Words

• blood pressure
• cardiovascular diseases
• endothelial function
• hypertension
• hypoxemia
• sleep-disordered breathing.

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MESH Headings

• Adult
• Aged
• Biomarkers/blood
• Endothelium, Vascular/physiopathology
• Female
• Humans
• Hyperemia/physiopathology
• Hypoxia/blood
• Hypoxia/diagnosis
• Hypoxia/etiology
• Hypoxia/physiopathology
• Male
• Middle Aged
• Oximetry
• Oxygen/blood
• Polysomnography
• Predictive Value of Tests
• Respiration
• Risk Factors
• Sleep
• Sleep Apnea Syndromes/complications
• Sleep Apnea Syndromes/diagnosis
• Sleep Apnea Syndromes/physiopathology
• Vascular Diseases/diagnosis
• Vascular Diseases/etiology
• Vascular Diseases/physiopathology
• Vasodilation

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Affiliation(s)

Hiroyuki Sawatari Department of Health Sciences, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Akiko Chishaki Department of Health Sciences, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Mari Nishizaka Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan; Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Tomotake Tokunou Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Sonomi Adachi Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan; Center for Clinical and Translational Research, Kyushu University Hospital, Fukuoka, Japan
Chikara Yoshimura Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan
Tomoko Ohkusa Kirameki Projects Career Support Center, Kyushu University Hospital, Fukuoka, Japan
Shin-ichi Ando Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan;

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Long-term antihypertensive effects of far-infrared ray irradiated from wooden board in spontaneously hypertensive rats

Background

Far-infrared ray (FIR) has been widely used in promoting health and has been shown to exert beneficial effects in vascular function. The non-thermal effect of FIR has been found to play a significant role in the protective effect on some vascular-related diseases, but its protective effects and use against hypertension have not been clearly presented.

Methods

In the present study, by using a wooden board coated with FIR-irradiated materials, we evaluated the long-term antihypertensive effect on spontaneously hypertensive rats (SHRs) in the environment in contact with the FIR-irradiated wooden board. SHRs were placed on the wooden board with or without FIR radiation for 4 weeks.

Results

The systolic blood pressure (BP) of SHRs undergoing different treatments was measured weekly using a tail-cuff method. FIR radiation significantly reduced the systolic BP of the SHRs along with a decreasing plasma level of angiotensin II and an increasing plasma level of bradykinin. In addition, long-term contact of FIR did not significantly affect the BP in normotensive Wistar Kyoto rats (WKYs).

Conclusions

Our results provided the evidence based on which FIR radiation could be considered an effective non-pharmacological choice for preventing hypertension.

The association between systemic oxidative stress and ocular blood flow in patients with normal-tension glaucoma

PURPOSE

To evaluate the association between ocular blood flow and biomarkers of systemic oxidative stress, as well as the potential of these biomarkers to assess normal-tension glaucoma (NTG).

METHODS

This study included 73 eyes of 73 patients with NTG. We assessed ocular blood flow by measuring mean blur rate (MBR) in the optic nerve head using laser speckle flowgraphy, both overall and separately in the vessel and tissue areas. We also measured urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and skin autofluorescence (SAF), and lastly, determined correlations between these measurements and with other clinical parameters.

RESULTS

SAF was correlated with age, circumpapillary retinal nerve fiber layer thickness (cpRNFLT), mean deviation (MD), and overall MBR (P = 0.003, P = 0.013, P = 0.015 and P = 0.006, respectively). SAF and 8-OHdG were both correlated with tissue-area MBR (P = 0.006 and P = 0.010, respectively). Visual acuity, cpRNFLT, mean deviation and tissue-area MBR had a significant tendency to change with NTG severity (P = 0.014, P < 0.001, P < 0.001 and P = 0.006, respectively). Multiple regression analysis revealed that cpRNFLT and 8-OHdG were independent contributing factors to MD (P < 0.001 and P = 0.040, respectively), and that cpRNFLT and 8-OHdG were independent contributing factors to tissue-area MBR (P = 0.005 and P = 0.028, respectively).

CONCLUSIONS

We found a close relationship between cpRNFLT, MD, tissue MBR, SAF and 8-OHdG, suggesting that systemic oxidative stress is associated with decreased ocular blood flow and may be involved in the pathogenesis of NTG.

Optical radiation in modern medicine

Optical radiation extends between microwaves and X-rays of the electromagnetic radiation and includes ultraviolet (UV), visible light (VL) and infrared (IR) components. The dose of radiation that reaches the skin is influenced by the ozone layer, position of the Sun, latitude, altitude, cloud cover and ground reflections. The photobiological effects of UV, VL and IR bands depend on their wavelength, frequency and mechanism of action. They are modified by the thickness, structure, vasculature and pigmentation of skin's stratum corneum, epidermis and dermis. Following absorption, IR affects the body mainly through transfer of thermal energy to tissues. Visible light and skin interact either thermally or photochemically, whereas UV acts mainly photochemically. Optical radiation in the form of sunlight therapy had been used already in ancient times. Nowadays IR, VL and UV are widely applied in the therapy of allergic, dermatological, cardiovascular, respiratory, rheumatic, neonatal, pediatric and psychiatric disorders.