Cold Water ImmersionNCT06667479
Cold Water Exposure and Immune Function Study
A study testing Cold Water Immersion (CWI) - Cold Tub Immersion (CI) and Cold Water Immersion (CWI) - Cold Shower (CS) in people with Cold Water Immersion and Immune Function, run by University of Northern Colorado at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Cold Water Immersion, Immune Function, Muscular Strength
- What is being tested?
- Cold Water Immersion (CWI) - Cold Tub Immersion (CI) and Cold Water Immersion (CWI) - Cold Shower (CS)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 37 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Oct 2024to 1 Mar 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Males and Females
- Aged 18-45
Who cannot join
- 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
Show all 9Show fewer
- Cancer
- Raynaud\'s Disease
- Severe and untreated anxiety or depression
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Northern Colorado - Gunter Hall
Greeley, Colorado, 80631
About this study
Official title: Effects of a 4 Week Cold Tub vs Cold Shower Immersion Intervention on Immune Function, Sleep Quality, Mental Health and Well-being, Gut Health, and Muscular Strength in Healthy, Physically Active Adults
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?
Read more
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
- Being tested
- Cold Water Immersion (CWI) - Cold Tub Immersion (CI), Cold Water Immersion (CWI) - Cold Shower (CS), Control Group (CO)
- Keywords
- Cold Water Immersion, Cold Tub, Cold Shower, Immune Function, Mental Health, Muscular Strength, Healthy Adults, Inflammation, Gut Health
- Medical subject headings
- Psychological Well-Being, Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
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 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
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.
| Study group | Role | What they receive |
|---|---|---|
| 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). Receives: 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). Receives: Other: Cold Water Immersion (CWI) - Cold Shower (CS) |
| Control Group (CO) | Other | Participants will not undergo any cold tub or cold shower intervention. Receives: Other: Control Group (CO) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Depression Anxiety and Stress Scales (DASS-21)
Participants will be asked to complete a paper version of the 21-item Depression Anxiety and Stress Scale (DASS-21). The DASS-21 consists of 21 questions using a 0-3 Likert scale assessing the participant's subjective mental health and stress state with a "0" indicating "Did not apply to me at all" and "3" indicating "Applied to me very much or most of the time." The DASS-21 contains 3 sub scales assessing Depression, Anxiety, and Stress consisting of 7 questions for each sub scale, where a high score of 28+ indicates "Extremely Severe" levels of Depression, a high score of 20+ indicates "Extremely Severe" levels of Anxiety, and a high score of 34+ indicates "Extremely Severe" levels of Stress, while low scores of 0-9 indicates "Normal" levels of Depression, scores of 0-7 indicates "Normal" levels of Anxiety, and scores of 0-14 indicates "Normal" levels of Stress.
Measured: Visit 1A (Week 1) and 2A (Week 4): 10 minutes each
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.
Measured: 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.
Measured: Visit 1A (Week 1) and Visit 2A (Week 4): 15 minutes for blood draw. The assay itself takes 3 hours.
Secondary outcomes (2)
Pittsburgh Sleep Quality Index (PSQI)
Participants will be asked to complete a paper version of the Pittsburgh Sleep Quality Index (PSQI). The PSQI is a 19-question self-reported sleep quality tool broken up into 7 subcategories for scoring, such as subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. There are also 5 additional questions directed to the respondent's roommate or bed partner not used in the scoring, but utilized for clinical purposes.
Measured: Visit 1A (Week 1) and 2A (Week 4): 10 minutes each
Handgrip Dynamometry
Isometric grip strength will be measured by a Baseline 12-0286 Electronic Smedly Hand Dynamometer (Fabrication Enterprises, White Plains, NY). To begin the test, participants will stand upright in a relaxed position; their upper extremity peak isometric grip strength will be assessed with the shoulder in 180º of flexion, elbow at full extension, and wrist and forearm in a neutral position. When prompted, participants will squeeze the device with their dominant hand, delivering a maximal effort for 3-seconds, followed by relaxation. After 30-seconds, the test will be run again. Three sets are completed for this test, and the highest value (kg) will be recorded for analysis.
Measured: Visit 1B (Week 1) and Visit 2B (Week 4): 10 minutes each
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Oct 2024
- Study start10 Oct 2024
- Primary completion1 Feb 2026
- Study completion1 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cold Water ImmersionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Parallel, randomized design, matched for biological age
- Masking
- None (open label)
- Enrolment
- 37 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Northern Colorado
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Laura Stewart, University of Northern Colorado
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06667479
- Sponsor's protocol ID
- 2404058883
- Status last verified
- Nov 2025
- First submitted
- 10 Oct 2024
- Last updated
- 7 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All study documents will be made available upon reasonable request (Laura.stewart@unco.edu).
Study at a glance
From the registry record, last updated by the sponsor on 7 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of a 4 Week Cold Tub vs Cold Shower Immersion Intervention on Immune Function, Sleep Quality, Mental Health and Well-being, Gut Health, and Muscular Strength in Healthy, Physically Active Adults
- ClinicalTrials.gov ID
- NCT06667479
- Acronym / sponsor ID
- 2404058883
- Keywords
- Cold Water Immersion, Cold Tub, Cold Shower, Immune Function, Mental Health, Muscular Strength, Healthy Adults, Inflammation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 37 participants (actual)
- Lead sponsor
- University of Northern ColoradoUniversity, hospital or other
- Study start
- 10 Oct 2024 (actual)
- Primary completion
- 1 Feb 2026 (actual)
- Study completion
- 1 Mar 2026 (actual)
- First posted
- 31 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- Parallel, randomized design, matched for biological age
| Arm | Type | Receives |
|---|---|---|
| Cold Tub Immersion Group (CI) | Experimental | Other: Cold Water Immersion (CWI) - Cold Tub Immersion (CI)Participants will utilize the research cold tub (10 ºC, 4-minutes, 3 times a week), following a standardized protocol (see intervention description). |
| Cold Shower Group (CS) | Experimental | Other: Cold Water Immersion (CWI) - Cold Shower (CS)Participants will utilize the research shower area (10 ºC, 4-minutes, 3 times a week), following a standardized protocol (see intervention description). |
| Control Group (CO) | Other | Other: Control Group (CO)Participants will not undergo any cold tub or cold shower intervention. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Males and Females
- Aged 18-45
Key exclusion criteria (9 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Cold Water Immersion (CWI) - Cold Tub Immersion (CI)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. | Other | Cold Tub Immersion Group (CI) |
| Cold Water Immersion (CWI) - Cold Shower (CS)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 | Other | Cold Shower Group (CS) |
| Control Group (CO)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. | Other | Control Group (CO) |
Primary outcome
Depression Anxiety and Stress Scales (DASS-21)
Time frame: Visit 1A (Week 1) and 2A (Week 4): 10 minutes each
Participants will be asked to complete a paper version of the 21-item Depression Anxiety and Stress Scale (DASS-21). The DASS-21 consists of 21 questions using a 0-3 Likert scale assessing the participant's subjective mental health and stress state with a "0" indicating "Did not apply to me at all" and "3" indicating "Applied to me very much or most of the time." The DASS-21 contains 3 sub scales assessing Depression, Anxiety, and Stress consisting of 7 questions for each sub scale, where a high score of 28+ indicates "Extremely Severe" levels of Depression, a high score of 20+ indicates "Extremely Severe" levels of Anxiety, and a high score of 34+ indicates "Extremely Severe" levels of Stress, while low scores of 0-9 indicates "Normal" levels of Depression, scores of 0-7 indicates "Normal" levels of Anxiety, and scores of 0-14 indicates "Normal" levels of Stress.
C-Reactive Protein
Time frame: Visit 1A (Week 1) and Visit 2A (Week 4): 15 minutes for blood draw. The assay itself takes 3 hours.
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.
Interleukin-6 (IL-6)
Time frame: Visit 1A (Week 1) and Visit 2A (Week 4): 15 minutes for blood draw. The assay itself takes 3 hours.
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.
2 secondary outcomes
Pittsburgh Sleep Quality Index (PSQI)
Time frame: Visit 1A (Week 1) and 2A (Week 4): 10 minutes each
Handgrip Dynamometry
Time frame: Visit 1B (Week 1) and Visit 2B (Week 4): 10 minutes each
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Oct 2026.
- Individual participant dataSharing planned: Yes. All study documents will be made available upon reasonable request (Laura.stewart@unco.edu).
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Cold Water Immersion (CWI) - Cold Tub Immersion (CI) and Cold Water Immersion (CWI) - Cold Shower (CS) in people with Cold Water Immersion and Immune Function, run by University of Northern Colorado at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Depression Anxiety and Stress Scales (DASS-21) (time frame: Visit 1A (Week 1) and 2A (Week 4): 10 minutes each). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Oct 2026.