Home-based Heat Therapy for Type 2 Diabetes

Study Overview
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Brief Summary
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Insulin resistance and hyperglycemia predispose individuals with type 2 diabetes mellitus (T2DM) to endothelial dysfunction and a greater risk of cardiovascular diseases (CVD). Increased CVD risk in individuals with T2DM persists despite optimal pharmacological therapy, highlighting the need to identify complementary lifestyle interventions that improve cardiometabolic functions in this population. Evidence from animal models suggests that heat exposure improves metabolic functions. Notably, weekly heat exposure for 16 weeks blunts hyperinsulinemia and hyperglycemia induced by a high fat diet in mice. In parallel, studies in humans have shown that heat exposure improves vascular endothelial function. Based on such findings, it has been suggested that heat therapy may represent an effective lifestyle intervention to improve cardiometabolic functions. However, only 1 study has examined the impact of a heat therapy intervention on individuals with T2DM, demonstrating that 6 weeks of heat exposure reduces fasting plasma glucose and hemoglobin A1C. No study has considered potential vascular benefits of heat therapy in individuals with T2DM. This project will investigate cardiometabolic responses to repeated heat exposure in men and women with T2DM. We will test the hypothesis that 12 weeks of heat therapy improves postprandial fatty acid handling, insulin sensitivity and endothelial function in individuals with T2DM.

Official Title
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Impact of a Home-based Heat Therapy Intervention on Markers of Cardiometabolic Function in Adults With Type 2 Diabetes

Conditions
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Diabetes Mellitus, Type 2, Heat Exposure

Intervention / Treatment
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* Other: Thermoneutral water
* Other: Hot water


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 45-75 years Diagnosis of type 2 diabetes mellitus ≥1 year Stable medication ≥12 weeks Exclusion Criteria: Class 3 obesity Hypertension not controled by medication Diagnosis of cardiac, renal and/or pulmonary disease Diagnosis of severe neuropathy and/or retinopathy Insulin therapy Fasting plasma triglycerides >5.0 mmol/L Fasting total cholesterol >7 mmol/l

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Thermoneutral<br>Participants will immerse their feet in a foot bath with water maintained at 36°C | Other: Thermoneutral water<br>* Participants will immerse their feet in a foot bath that contains thermoneutral water<br>|
| Experimental: Heat<br>Participants will immerse their feet in a foot bath with water maintained at 42°C | Other: Hot water<br>* Participants will immerse their feet in a foot bath that contains hot water<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hemoglobin A1C (HbA1C) |  | Change from baseline to 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insulin resistance (HOMA-IR) |  | Change from baseline to 12 weeks | 
| Postprandial metabolism following meal | Quantified over a 6-hour period following the ingestion of a standardized liquid meal | Change from baseline to 12 weeks | 
| Peripheral endothelial function | Brachial artery flow-mediated dilation | Change from baseline to 12 weeks | 
| Post-occlusion reactive hyperemia | Reactive hyperemia following 5 minutes of forearm ischemia | Change from baseline to 12 weeks | 
| Ischemic handgrip exercise | Reactive hyperemia following ischemic handgrip exercise | Change from baseline to 12 weeks | 
| Arterial stiffness | Carotid-femoral pulse wave velocity | Change from baseline to 12 weeks | 
| Blood pressure | 24-hour ambulatory blood pressure monitoring | Change from baseline to 12 weeks |