The aim of this study was to evaluate efficacy and applicability of the “intermittent hypoxic-hyperoxic exposures at rest” (IHHE) protocol as an adjuvant method for metabolic syndrome (MS) cardiometabolic components. A prospective, single-center, randomized controlled clinical study was conducted on 65 patients with MS subject to optimal pharmacotherapy, who were randomly allocated to IHHE or control (CON) groups. The IHHE group completed a 3-week, 5 days/week program of IHHE, each treatment session lasting for 45 min. The CON group followed the same protocol, but was breathing room air through a facial mask instead. The data were collected 2 days before, and at day 2 after the 3-week intervention. As the primary endpoints, systolic (SBP) and diastolic (DBP) blood pressure at rest, as well as arterial stiffness and hepatic tissue elasticity parameters, were selected. After the trial, the IHHE group had a significant decrease in SBP and DBP (Cohen’s d = 1.15 and 0.7, p < 0.001), which became significantly lower (p < 0.001) than in CON. We have failed to detect any pre-post IHHE changes in the arterial stiffness parameters (judging by the Cohen’s d), but after the intervention, cardio-ankle vascular indexes (RCAVI and LCAVI) were significantly lowered in the IHHE group as compared with the CON. The IHHE group demonstrated a medium effect (0.68; 0.69 and 0.71 Cohen’s d) in pre-post decrease of Total Cholesterol (p = 0.04), LDL (p = 0.03), and Liver Steatosis (p = 0.025). In addition, the IHHE group patients demonstrated a statistically significant decrease in pre-post differences (deltas) of RCAVI, LCAVI, all antropometric indices, NTproBNP, Liver Fibrosis, and Steatosis indices, TC, LDL, ALT, and AST in comparison with CON (p = 0.001). The pre-post shifts in SBP, DBP, and HR were significantly correlated with the reduction degree in arterial stiffness (ΔRCAVI, ΔLCAVI), liver fibrosis and steatosis severity (ΔLFibr, ΔLS), anthropometric parameters, liver enzymes, and lipid metabolism in the IHHE group only. Our results suggested that IHHE is a safe, well-tolerated intervention which could be an effective adjuvant therapy in treatment and secondary prevention of atherosclerosis, obesity, and other components of MS that improve the arterial stiffness lipid profile and liver functional state in MS patients.

Introduction Metabolic syndrome (MS) as a “cluster” of interrelated disorders, including insulin resistance, visceral obesity, dyslipidemia, and hypertension, is an serious clinical problem that is a high risk factor for the development of type 2 diabetes, acceleration of the development and progression of cardiovascular diseases, and such increasingly common liver damage like non-alcoholic fatty liver disease. According to a number of authors, metabolic syndrome is a reversible condition, and with early diagnosis and treatment, a reduction in the severity of manifestations of this syndrome can be achieved. A significant role in the treatment of MS and obesity is played by non-drug methods – dosed physical activity, diet, various physiotherapeutic procedures, as well as interval hypoxic-hyperoxic training (IHHT). Objective Evaluation of the effect of interval hypoxic-hyperoxic training (IHHT) on the components of metabolic syndrome, and the possibility of their reversal recovery. Materials and methods The study included 65 patients (33 men) with metabolic syndrome, aged 29–66 years. The patients were divided into 2 groups: study and control (the groups were matched by sex, age, presence of MS components and number of comorbidities). Initially, anthropometric, laboratory and instrumental studies were carried out. The patients of the main group underwent a course of IHHT for 3 weeks, 5 days a week (15 workouts). Patients in the control group underwent a course of training simulating IHHT (placebo), which also consisted of 15 trainings. The duration of one procedure was 40 minutes. Next day after the end of the training course, the changes in all initial parameters were assessed. Results The statistical significance of changes after the IGGT course was assessed using the Wilcoxon test as p&lt;0.05 and was detected in the main group according to the following parameters: reduction in arterial stiffness, measured using CAVI (Cardio-Ankle Vascular Index, on the Fukuda Denshi ap.), a decrease in the stage of liver fibrosis and stiffness of liver tissue (was realized by a non-invasive method, a liver elastometry, on the FibroScan ap. Echosense), a decrease in high-sensitivity C-reactive protein, heat shot protein-70, a decrease in total cholesterol, low density lipoproteins, triglycerides levels. According to nitric oxide, transforming growth factor beta-1, heart-type fatty acid binding protein, there was no significant dynamics after the IHHT course in both groups. There was also a tendency towards a decrease in the indices of the abdominal/hip circumference, weight, and in blood pressure, but this results was not statistically significant, due to the insufficient power of the study (a small number of patients). Conclusions IHHT is a safe, well-tolerated procedure and is recommended in the therapeutic and prophylactic plan for patients with metabolic syndrome, and is effective in correcting and minimizing the components of this syndrome. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): This work was financed by the Ministry of Science and Higher Education of the Russian Federation within the framework of state support for the creation and development of World-Class Research Centers “Digital biodesign and personalized healthcare”