Obesity represents the excessive or abnormal accumulation of adipose tissue in the body, which affects health through its association with the risk of developing diabetes mellitus, cardiovascular and pulmonary diseases and hypertension.

Obesity can cause significant respiratory changes, so obese patients present pulmonary complications more frequently than individuals with normal weight.

Intermittent hypoxia (IH) represents the alternation between repeated episodes of hypoxia interspersed with normoxic episodes. Intermittent hypoxia-hyperoxia is the therapy that uses hyperoxic intervals instead of normoxic ones between hypoxic breathing sessions.

This study aimed to evaluate the effectiveness of intermittent hypoxia-hyperoxia therapy among obese patients, focusing on metabolic and respiratory effects. The study aimed to determine if this method could bring benefits in managing or alleviating the complications associated with obesity.

A total of 70 obese patients will be recruited and randomized to either the IHHT group or the control group. The intervention group will receive IHHT while the control group will not receive this therapy.

All patients will be assessed at baseline and after 2 weeks of treatment using a variety of clinical and functional measures. The study's results will be used to determine whether IHHT benefits the patients who follow it.

This study is designed to contribute to the existing body of knowledge on treating obese patients. The results of the study will be of interest to clinicians, researchers, and patients.

The study was a prospective, randomized controlled, unicentric study conducted at the Balneal and Rehabilitation Sanatorium Techirghiol (BRST) in Romania. A total of 70 obese patients (BMI > 30 kg/m2) were enrolled in the study. The patients were randomly assigned to either the IHHT group or the control group.

Patients in the intervention group received intermittent hypoxia-hyperoxia therapy and patients in the control group did not receive this therapy. Simultaneously with the intermittent hypoxia-hyperoxia therapy, the patients benefited from complex balneo-physical-kinetic treatment which included hydrokinetotherapy and hydrothermotherapy using specific natural environmental factors: sapropelic mud and salt water from Lake Techirghiol, electrotherapy, massage therapy and kinetotherapy.

The 35 patients in the IHHT group underwent intermittent hypoxia-hyperoxia therapy using the CellOxy Device. During the hypoxic phases, patients received concentrations of 9-16% O2, while during the hyperoxic phases, approximately 35% O2 was administered.

During both testing and actual therapy sessions, patients remained in a comfortable position, lying on a bed. Initially, patients performed hypoxic tests 1 and 2, to determine the optimal oxygen level and to be included in a typology (type I, II, or III). Based on the obtained data, the device automatically calculated and planned personalized IHHT sessions for each patient.

Starting from the following day, patients in the IHHT group were subjected to intermittent hypoxia-hyperoxia as follows: hypoxia with 9-16% O2 for 5-7 minutes, followed by exposure to hyperoxia with ~35% O2 for 2-5 minutes. During the sessions, both SpO2 and heart rate were constantly monitored using the device's built-in pulse oximeter.

In total, patients in the IHHT group performed 9 sessions of hypoxic-hyperoxic therapy: testing on the first day (hypoxic tests 1 and 2), followed by 4 days of sessions in the first week, 2 days of rest on the weekend and then another 5 days of sessions in the second week.

The initial assessment of patients consisted of a comprehensive medical examination, which identified their comorbidities, family history, verification of medication for associated pathologies and behavioral factors (smoking, alcohol consumption, psychosocial stress).

All patients underwent the following measurements: resting blood pressure (BP), heart rate (HR), blood oxygen saturation (SpO2), anthropometric data: height (cm), body weight (kg), waist circumference (cm), and hip circumference (cm), BMI calculation, blood sampling (urea, uric acid, creatinine, glucose, total cholesterol, AST, ALT). Regardless of the presence or absence of changes in the analysis results, patients were included in the study. We consider it important to investigate the entire spectrum of the studied patients, including those with evident changes in their analyses and those with normal results, to obtain a comprehensive and representative image of the researched phenomenon. The patients also performed a 6-minute walk test and a spirometry.

After completing the 2 weeks of treatment at the Balneal and Rehabilitation Sanatorium of Techirghiol, the final assessment identified the same parameters as followed initially.

The statistical analysis was performed using IBM SPSS statistics software version 25. Data are presented as mean ± standard deviation (SD) for continuous variables in case of symmetric distributions, median and IQR (Interquartile range IQR = P75-P25) for numerical discrete variables or for continuous variables in case of skewed distributions, or as frequencies and percentages for categorical variables. The normality of the continuous data was estimated with Shapiro-Wilk Tests of Normality. For hypotheses testing: Independent Samples Mann Whitney U test, Related Samples Wilcoxon Signed Rank Test, Chi-Square Test of association, were used depending on the type of analyzed variables. Spearman's correlation coefficient was used as a statistical measure of the strength of a relationship between paired data. The significance level α was set at 0.05. If the test statistic for every conducted test was in the critical region, and the p-value was less than or equal to the significance level, we decided to reject the null hypothesis in favor of the alternative hypothesis.

Inclusion Criteria:

• patients with BMI >30 kg/m2
• aged between 40-75 years
• patients to sign the informed consent form
• patients to be compensated and to have medical treatment for associated pathologies

Exclusion Criteria:

• BMI <30 kg/m2
• age under 40 or over 75 years
• refusal to sign the informed consent form
• patients presenting contraindications to intermittent hypoxia-hyperoxia therapy
• patients presenting contraindications to complex medical rehabilitation treatment