Cold Water Exposure and Immune Function Study

NCT06667479 | Completed

• 1 other identifier: 2404058883
• Study Type: interventional
• Target: 37
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this clinical trial is to explore the effects of a 4 week cold-water immersion (CWI) intervention on measures of immune function, sleep quality, mental health and well-being, and muscular strength. The main questions it aims to answer are:

• Does a 4 week CWI intervention improve measures of immune function, sleep quality, mental health and well-being, and muscular strength?
• Are there any differences in these measures when comparing cold tubs versus cold showers? Researchers will compare chronic use of cold tubs to cold showers to see if cold water immersion may improve overall immune health and well-being. Participants will:
• Undergo 4 weeks of Cold Tub or Cold Shower interventions at a frequency of 3 times a week for 4 minutes, if placed in the CWI intervention groups
• Undergo testing measures at the two pre- and post- intervention time points, if placed in the healthy control group or the CWI intervention groups

Conditions

Cold Water Immersion; Immune Function; Muscular Strength; Mental Health

Keywords

Cold Water Immersion; Cold Tub; Cold Shower; Immune Function; Mental Health; Muscular Strength; Healthy Adults; Inflammation; Gut Health

Outcome Measures

Primary Outcomes (2)

• C-Reactive Protein

  Approximately 60mL of whole blood will be collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA), allowed to clot for 30-min at room temperature, then centrifuged at 2000 RPM for 15 min. The serum will be pipetted into 1.5 mL microcentrifuge tubes (Eppendorf AG, Hamburg, Germany) and immediately stored in a -80 °C freezer. Serum concentrations of CRP will be determined with a commercially available enzyme-linked immunosorbent assay (ALPCO Diagnostics, Salem, NH, USA). Microplates will be read with an ELx800 BioTek microplate reader (BioTek Instruments, Inc., Winooski, VT, USA) at the recommended wavelength of 450 nanometers.

  Visit 1A (Week 1) and Visit 2A (Week 4): 15 minutes for blood draw. The assay itself takes 3 hours.

• Interleukin-6 (IL-6)

  Approximately 60mL of whole blood will be collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA), allowed to clot for 30-min at room temperature, then centrifuged at 2000 RPM for 15 min. The serum will be pipetted into 1.5 mL microcentrifuge tubes (Eppendorf AG, Hamburg, Germany) and immediately stored in a -80 °C freezer. Serum concentrations of IL-6 will be determined with a commercially available enzyme-linked immunosorbent assay (Thermo Fisher Scientific, Waltham, MA, USA). Microplates will be read with an ELx800 BioTek microplate reader (BioTek Instruments, Inc., Winooski, VT, USA) at the recommended wavelength of 450 nanometers.

  Visit 1A (Week 1) and Visit 2A (Week 4): 15 minutes for blood draw. The assay itself takes 3 hours.

Secondary Outcomes (3)

• Pittsburgh Sleep Quality Index (PSQI)

  Visit 1A (Week 1) and 2A (Week 4): 10 minutes each

• Depression Anxiety and Stress Scales (DASS-21)

  Visit 1A (Week 1) and 2A (Week 4): 10 minutes each

• Handgrip Dynamometry

  Visit 1B (Week 1) and Visit 2B (Week 4): 10 minutes each

Other Outcomes (6)

• Lean Body Mass

  Visit 1A (Week 1) and Visit 2A (Week 4): 20 minutes each

• Body Fat Percentage

  Visit 1A (Week 1) and Visit 2A (Week 4): 20 minutes each

• Immune Status Questionnaire (ISQ)

  Visit 1A (Week 1): 5 minutes

Study Arms (3)

Cold Tub Immersion Group (CI)

EXPERIMENTAL

Participants will utilize the research cold tub (10 ºC, 4-minutes, 3 times a week), following a standardized protocol (see intervention description).

Other: Cold Water Immersion (CWI) - Cold Tub Immersion (CI)

Cold Shower Group (CS)

EXPERIMENTAL

Participants will utilize the research shower area (10 ºC, 4-minutes, 3 times a week), following a standardized protocol (see intervention description).

Other: Cold Water Immersion (CWI) - Cold Shower (CS)

Control Group (CO)

OTHER

Participants will not undergo any cold tub or cold shower intervention.

Other: Control Group (CO)

Interventions

Cold Water Immersion (CWI) - Cold Tub Immersion (CI) OTHER

Once thermoneutral procedures are complete, participants in the CI group will be seated in the cold tub and submerged into the water (10º C). The sternal notch of each participant will be used as the anatomical marker to mark submersion point. Participants will sit with both arms outstretched underwater with their backs not touching the sides of the tub. Participants with a shorter stature will be provided an underwater cushion to meet the submersion requirements. The 4-minute timer will begin once confirmation of the participants submersion level and posture is determined. Once completed, the participant will be instructed to slowly exit the tub and allowed to dry and change as necessary.

Cold Tub Immersion Group (CI)

Control Group (CO) OTHER

Participants will be encouraged to maintain their current diet and exercise across the duration of the 4 week intervention. Participants will still be subjected to the pre- and post-intervention data collection session.

Control Group (CO)

Cold Water Immersion (CWI) - Cold Shower (CS) OTHER

Once thermoneutral procedures are complete, participants in the CS group will be instructed to enter the research shower area. Within the shower area, the walls of the shower will be numbered from 1 to 4, with 1 defined as facing the faucet, 2 defined as 90° to the right of side 1, 3 defined as 180° from the faucet, and 4 defined as 270° to the right or 90° C to the left from side 1. Participants will be instructed to turn 90° to the right cycling through sides 1 to 4 and then back to 1 every 15 seconds prompted by the researcher. This will allow the participant to complete four full rotations in the shower during the 4-minute intervention time. The shower faucet is modified and oriented in a way where it only produces cold water (10º C) when turned on. Once completed, the participant will be instructed to slowly exit the shower and is allowed to dry and change as necessary

Cold Shower Group (CS)

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Males and Females
• Aged 18-45

You may not qualify if:

• Currently practices CWI for \[\>3 times in the last month\]
• Pregnant or planning to become pregnant
• Chronic use of anti-inflammatory medication
• Prior history of chronic disease conditions:
• Cardiovascular Disease
• Diabetes
• Cancer
• Raynaud\'s Disease
• Severe and untreated anxiety or depression

Sponsors & Collaborators

• University of Northern Colorado: lead

Study Sites (1)

University of Northern Colorado - Gunter Hall

Greeley, Colorado, 80631, United States

Location

MeSH Terms

Conditions

Psychological Well-Being; Inflammation

Interventions

Control Groups

Condition Hierarchy (Ancestors)

Personal Satisfaction; Behavior; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Epidemiologic Research Design; Epidemiologic Methods; Investigative Techniques; Research Design; Methods

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Parallel, randomized design, matched for biological age

Study Record Dates

• First Submitted: October 10, 2024
• First Posted: October 31, 2024
• Study Start: October 10, 2024
• Primary Completion: February 1, 2026
• Study Completion: March 1, 2026
• Last Updated: March 10, 2026

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will share
• Time Frame: Oct 1, 2025 - Oct 1, 2028
• Access Criteria: Individuals will email Laura.stewart@unco.edu with a request for study materials.

Locations

US (1)