Cold and Heat Investigation to Lower Levels of Depression (CHILL'D)

This study will recruit 112 medically healthy adults (aged 18-65) currently experiencing depressive symptoms to be randomized to receive either a single Whole Body Hyperthermia (heat therapy) treatment or a Whole Body Hyperthermia treatment followed by a cold water plunge. Participants will complete a baseline assessment of their depressive symptoms as well as 1-week and 2-week post-treatment followup assessments.

Study Overview

• Status: Recruiting
• Conditions: Depression; Mood Disorders; Healthy (Controls)
• Intervention / Treatment: Procedure: Whole Body Hyperthermia; Procedure: Cold Water Plunge

Detailed Description

The CHILL'D Study aims to figure out how using heat exposure as a treatment for major depressive disorder (MDD) can work better. The researchers want to see if being exposed to heat followed by cold plunge can help people feel better emotionally compared to just being exposed to heat alone.

To answer study questions, 112 adults, ages 18 to 65 experiencing depression for at least 60 days and who meet study eligibility criteria, will be randomized with 1-to-1 allocation to receive either 1) a single session of heat exposure or 2) a single session of heat exposure followed immediately by cold plunge.

A second cohort of up to 50 adults, ages 18 to 65 not experiencing MDD will be randomized with 1-to-1 allocation to the same interventions.

Participants in the heat exposure alone group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes. Participants in the heat exposure and cold plunge group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes followed by a cold plunge session lasting up to 10 minutes.

• Study Type: Interventional
• Enrollment (Estimated): 162
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Study Coordinator; Phone Number: 970-855-7374; Email: BHIC@vailhealth.org

Study Locations

• United States
  • Colorado
    • Edwards, Colorado, United States, 81632
      • Recruiting
      • Vail Health Behavioral Health Innovation Center
      • Contact: Study Coordinator; Phone Number: 970-445-2489; Email: BHIC@vailhealth.org
      • Principal Investigator: Barry Sandler, DO

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Individuals who currently meet study criteria for depression or individuals who do not currently meet criteria for depression
• English or Spanish speaking (able to provide informed consent and complete questionnaires in one of these languages)
• Able and willing to adhere to trial requirements, including attending all trial visits, preparatory and follow-up sessions, and completing all trial evaluations.

Exclusion Criteria:

• Previous adverse reaction to hypothermia, hyperthermia and/or infrared exposure
• Use of any medication that may impact thermoregulatory capacity.
• Pregnancy, active lactation, or intention to become pregnant during the study period.
• Endorses current active suicidal ideation with a plan or made a suicide attempt in the prior 6 months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Depression + Whole Body Hyperthermia; Participants experiencing depression will receive a single heat treatment using the Clearlight Sauna Dome lasting up to 140 minutes.	Procedure: Whole Body Hyperthermia; Participants in the heat exposure alone group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes; Other Names: Infrared Sauna; Whole Body Heating
Active Comparator: Depression + Whole Body Hyperthermia + Cold Water Plunge; Participants experiencing depression will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes followed by a cold plunge session lasting up to 10 minutes.	Procedure: Whole Body Hyperthermia; Participants in the heat exposure alone group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes; Other Names: Infrared Sauna; Whole Body Heating; Procedure: Cold Water Plunge; Participants in the heat exposure and cold plunge group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes followed by a cold plunge session in 55 degree (Fahrenheit) water, lasting up to 10 minutes.; Other Names: Cold Plunge; Cold Water Exposure
Active Comparator: No Depression + Whole Body Hyperthermia; Participants not experiencing depression will receive a single heat treatment using the Clearlight Sauna Dome lasting up to 140 minutes.	Procedure: Whole Body Hyperthermia; Participants in the heat exposure alone group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes; Other Names: Infrared Sauna; Whole Body Heating
Active Comparator: No Depression + Whole Body Hyperthermia + Cold Water Plunge; Participants not experiencing depression will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes followed by a cold plunge session lasting up to 10 minutes.	Procedure: Whole Body Hyperthermia; Participants in the heat exposure alone group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes; Other Names: Infrared Sauna; Whole Body Heating; Procedure: Cold Water Plunge; Participants in the heat exposure and cold plunge group will receive a single heat session using the Clearlight Sauna Dome lasting up to 140 minutes followed by a cold plunge session in 55 degree (Fahrenheit) water, lasting up to 10 minutes.; Other Names: Cold Plunge; Cold Water Exposure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Montgomery-Åsberg Depression Rating Scale (MADRS)	The MADRS is a validated 10-item questionnaire to assess depression severity and is commonly used to assess efficacy of an intervention in clinical trials. Each item of the MADRS is measured on a scale of 0 to 6 (for a total score of 0 to 60) with higher scores indicating more severe depression. The MADRS includes questions on the following symptoms: 1. Reported sadness; 2. Apparent sadness; 3. Inner tension; 4. Reduced sleep; 5. Reduced appetite; 6. Concentration difficulties; 7. Lassitude; 8. Inability to feel; 9. Pessimistic thoughts; 10. Suicidal thoughts. Items are scored via a clinical interview that progresses from more broadly phrased questions about symptoms to more detailed queries that allow a precise rating of severity.	Baseline/Treatment (Visit 1), 1 Week Post-Treatment (Visit 2), 2 Weeks Post-Treatment (Visit 3)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Warwick Edinburgh Mental Well-Being Scale (WEMWBS)	The WEMWBS was designed to measure the psychological well-being of a population and has been shown to be responsive to novel interventions such as psychedelics. WEMWBS has 14 questions scored using a five-point Likert scale. The items are all worded positively and cover both feeling and functioning aspects of mental wellbeing. Items on the questionnaire are rated on a 5-point scale, where 1= "None of the time", 2= "rarely", 3= "some of the time", 4= "often", 5= "all the time". Scores reflect feelings and thoughts in the two weeks prior to answering the questionnaire. The WEMWBS assesses both emotional and functional aspects of mental well-being. Total scores range from 14 to 70, with higher scores correlating to higher levels of well-being.	Baseline/Treatment (Visit 1), 1 Week Post-Treatment (Visit 2), 2 Weeks Post-Treatment (Visit 3)
Patient Reported Outcome Measure Information System (PROMIS) 8A - Anxiety	The PROMIS Anxiety measure focuses on fear (e.g., worry, feelings of panic), anxious misery (e.g., dread), hyperarousal (e.g., tension, nervousness, restlessness), and somatic symptoms related to arousal (e.g., cardiovascular symptoms, dizziness) and has been found to be a clinically validated measure of anxiety. The PROMIS 8A--Anxiety is comprised of eight items, each rated on a scale from 1 ("Never") to 5 ("Always"). Total scores range from 8 to 40, with higher scores correlating to higher levels of anxiety.	Baseline/Treatment (Visit 1), 1 Week Post-Treatment (Visit 2), 2 Weeks Post-Treatment (Visit 3)
Sheehan Disability Scale (SDS)	The SDS is a composite of 3 self-rated items designed to measure the extent to which 3 major sectors in the patient's life are impaired by psychiatric symptoms, including depression. This scale has been used widely in psychopharmacology randomized, controlled trials and has been accepted by the Food and Drug Administration (FDA) for functional disability labeling. The SDS uses visual-spatial, numeric, and verbal descriptive anchors simultaneously to assess disability across 3 domains: work, social life, and family life. The SDS asks participants to rate the extent to which their 1) work/school, 2) social life or leisure activities, and 3) home life or family responsibilities are impaired by his or her symptoms on a 10-point visual analogue scale. Total scores range from 0 to 30, with higher scores correlating to higher levels of disability.	Baseline/Treatment (Visit 1), 1 Week Post-Treatment (Visit 2), 2 Weeks Post-Treatment (Visit 3)
Quality of Life Enjoyment & Satisfaction Questionnaire Short Form (Q-LES-Q SF)	The Quality of Life Enjoyment and Satisfaction Questionnaire - Short Form version contains 16 items assessing changes in quality of life, divided into the following sections: physical health, feelings, work, household duties, school, leisure time activities, social relations, and general activities. A total score is derived from summing the first 14 items on the scale, with the last 2 items serving as stand-alone queries. Total score ranges from 14 to 70, with higher scores correlating with higher levels of quality of life.	Baseline/Treatment (Visit 1), 1 Week Post-Treatment (Visit 2), 2 Weeks Post-Treatment (Visit 3)

Collaborators and Investigators

• Sponsor: Barry Sandler
• Collaborators: Steadman Philippon Research Institute
• Investigators: Principal Investigator: Barry Sandler, DO, Vail Health Behavioral Health

Study record dates

Study Major Dates

• Study Start (Actual): May 14, 2024
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: February 8, 2024
• First Submitted That Met QC Criteria: February 8, 2024
• First Posted (Actual): February 16, 2024

Study Record Updates

• Last Update Posted (Estimated): November 13, 2025
• Last Update Submitted That Met QC Criteria: November 11, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Depression; Mental Health; Mood Disorders; Hyperthermia; Sauna; Integrative Health; Cold Plunge
• Additional Relevant MeSH Terms: Mental Disorders; Wounds and Injuries; Behavioral Symptoms; Body Temperature Changes; Heat Stress Disorders; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Personal Satisfaction; Hyperthermia; Depression; Mood Disorders; Psychological Well-Being
• Other Study ID Numbers: 20244106

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified data including, but not limited to, demographics, questionnaires, and adverse events will be made available upon request.
• IPD Sharing Time Frame: Following publication of primary study findings.
• IPD Sharing Access Criteria: De-identified data will be made available to qualified researchers in a way that protects subject confidentiality and adheres to HIPAA policies. Both internal and external requests for data will be handled by the study team to ensure equitable access, fairness, and safeguards. After reviewing a short proposal prepared by an external investigator, the study team will approve requests with appropriate experimental design, scientific merit, and Institutional Review Board (IRB) approval and recommend revisions for proposals requiring further justification or modifications. Informed consent documents will provide sufficient detail about the intent to archive, share, and re-analyze data.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No