The Effects of Passive Heat Therapy in Patients With Chronic Kidney Disease

Study Overview
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Brief Summary
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The objective of this proposal is to investigate the acute effects of whole-body passive heat therapy using far-infrared technology on vascular function, exercise capacity, and renal function in CKD patients. The central hypothesis is that an acute bout of whole-body passive heat therapy will be well-tolerated and lead to acute improvements in large blood vessel (macrovascular) function, small blood vessel (microvascular) function, and exercise capacity without significantly altering markers of acute kidney injury.

Official Title
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The Effects of Passive Heat Therapy in Patients With Chronic Kidney Disease

Conditions
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Renal Insufficiency, Chronic

Intervention / Treatment
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* Procedure: Whole-body Passive Heat Therapy (HT)
* Procedure: Thermoneutral Control (CON)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria for participants with CKD: Age > 18 years old Stage 2-4 CKD Inclusion Criteria for healthy participants: Age > 18 years old Matched in age and sex to the CKD sample Exclusion Criteria for participants with CKD: Unstable medical conditions characterized by frequent or unpredictable biological, chemical, or psychological changes Uncontrolled hypertension Current fluid restrictions End stage kidney disease or currently on dialysis treatment Body weight < 40kg Exhibits any contraindications to exercise as per ACSM guidelines Regular tobacco and/or nicotine use History of heat-related illness Participates in regular exercise and/or sauna use Current hormone replacement therapy Pacemaker or electro-medical implant Persons with or at risk of intestinal disorders including gastroporesis History of diverticula Persons who have undergone surgical procedures in the GI tract Swallowing disorders Chron's disease Current pregnancy Inability to provide informed consent Exclusion Criteria for healthy participants: Current chronic disease Current hormone replacement therapy Body weight < 40kg Exhibits any contraindications to exercise as per ACSM guidelines History of heat-related illness Pacemaker or electro-medical implant Persons with or at risk of intestinal disorders including gastroporesis History of diverticula Persons who have undergone surgical procedures in the GI tract Swallowing disorders Chron's disease Current pregnancy Inability to provide informed consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental Arm: Whole-body Passive Heat Therapy (HT)<br>Heat therapy will be administered using an infrared sauna. The intervention duration will last 25 minutes at a temperature of 60°C. | Procedure: Whole-body Passive Heat Therapy (HT)<br>* The whole-body passive heat therapy (HT) intervention will consist of an acute bout of infrared sauna for 25 minutes at 60°C. Participants will lie supine on a memory foam pad.<br>|
| Active Comparator: Control Arm: Thermoneutral Control (CON)<br>The control arm will consist of 25 minutes in a thermoneutral environment to serve as a comparator condition. Participants will be exposed to the exact conditions as the intervention arm, however, the temperature of exposure will be 22°C. | Procedure: Thermoneutral Control (CON)<br>* Participants will remain in a room temperature environment (22°C) underneath the infrared domes for 25 minutes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Renal Safety of Heat Therapy | Change in urinary NGAL | Change from baseline to 90 minutes after intervention | 
| Tolerability of Heat Therapy as Assessed using Validated Questionnaires of Thermal Perception | Self reported perception of heat using the the Thermal Sensation Scale. | During 25 minute intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Conduit artery endothelial function | Brachial artery flow-mediated dilation assessed by high-resolution duplex ultrasound. | 90 minutes after intervention | 
| Lower Limb Microvascular Function | Lower limb microvascular function will be assessed with high-resolution duplex ultrasound during passive leg movement (PLM) technique. | 90 minutes after intervention | 
| Exercise Capacity | The 6-minute walk test distance. | 90 minutes after intervention |