The human resources required to start enrollment were not available anymore.

Type 2 diabetes mellitus (T2DM) is a significant burden worldwide. In addition to lifestyle intervention, heat therapy has been shown to be effective in improving glycemic control. To date, there are no randomized, controlled trials investigating the efficacy of heat therapy in T2DM. Our aim is to investigate whether heat therapy with natural mineral water can improve blood glucose status in T2DM patients.

The HEATED study is a two-arm, randomized, controlled study. Patients with T2DM were randomly assigned to Group A (bath in 38 ° C natural thermal mineral water) or Group B (bath in thermoneutral water - 30-32 ° C). Both groups participate in up to five interventions per week, representing 50 to 60 heat therapies over the 12-week study. Each intervention lasts 30 minutes, preceded by a medical examination.

Type 2 diabetes mellitus (T2DM) is a significant burden worldwide. In addition to lifestyle intervention, heat therapy has been shown to be effective in improving glycemic control. To date, there are no randomized, controlled trials investigating the efficacy of heat therapy in T2DM. The study aims to investigate whether heat therapy with natural mineral water can improve blood glucose status in T2DM patients.

The HEATED study is a two-arm, randomized, controlled study. Patients with T2DM will be randomly assigned to Group A (bath in 38 ° C natural thermal mineral water) or Group B (bath in thermoneutral water - 30-32 ° C). Both groups will participate in up to five interventions per week, representing 50 to 60 heat therapies over the 12-week study. Each intervention will last 30 minutes, preceded by a medical examination. At baseline, patients' T2DM status will be recorded and possible micro- and macrovascular complications of T2DM are assessed by physical and laboratory tests. In addition, sensory and autonomic neuropathy will be assessed using Neurometer, Neuropad, and 128 Hz tuning fork tests. Quality of life will be assessed using the SF-36 questionnaire. In addition to baseline, patient data will be recorded at 4, 8, and 12 weeks. During routine blood collection, biobank storage will be performed via plus blood samples collection.

The primary endpoint will be the change from baseline in glycated hemoglobin by week 12 in both groups. Based on a preliminary estimate of the number of items, 65 patients per group are planned to be included in the HEATED study.

The results of the study described above may provide information on the utility of heat therapy in type 2 diabetics. Using the samples stored in the biobank, further analyzes will be performed at the end of the study.

Inclusion Criteria:

• patient with type 2 diabetes diagnosed according to the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) guidelines
• serum glycated hemoglobin (HbA1c) level between 7 and 10% (53-86 mmol/mol)
• signed written informed consent form

Exclusion Criteria:

• other types of diabetes mellitus
• patients with poor glycaemic control or unstable diabetes
• patients with known serious comorbidity and/ or with advanced macrovascular complications
• active bacterial infection or treatment with antibiotics within 3 weeks
• open wounds or skin lesions
• history of skin-related conditions or sensitivity to prolonged water immersion or exposure to pool chemicals
• severe psychiatric pathology or psychosis
• pregnancy or breastfeeding
• judgment by medical provider that heat therapy/ hydrotherapy poses an undue burden or risk
• participating in other ongoing clinical trials
• heat or balneotherapy in the past 3 months
• morbid obesity (body mass index > 40 kg/m2)
• steroid treatment
• active autoimmune diseases
• coronavirus disease 2019 (COVID-19) in the past 3 months