NCT06667193

Brief Summary

An interest in cold-water immersion (CWI) to elicit diverse physiological effects has been prevalent for centuries. CWI typically consists of bodily exposure to water at temperatures ranging from 5-10º C for various durations. CWI has profound cultural significance in different areas of the world, such as in Scandinavian countries, and has emerged as a popular modality for its purported health-promoting effects. Individuals on social media have repeatedly advocated for CWI as a method to improve muscular recovery, enhance sleep, and increase immune and cognitive function. Because of this, companies that specialize in cold tub production have become popularized; however, individuals who are seeking a more cost-effective option are drawn toward cold showers for their preferred method of cold exposure. Despite the scarcity of rigorous research investigating the difference in effects of cold tub versus cold shower CWI, individuals on social media promoting CWI via a shower continue to praise its comparable benefits to that of a tub. Therefore, investigations of chronic CWI (utilizing both a cold tub and a cold shower) is vital. Thus, the purpose of the proposed study is to explore the varying effects of chronic CWI on neural and cognitive function using a cold tub and a cold shower. Further, the study aims to investigate performance measures and immune measures to create a comprehensive understanding of CWI's implications on human physiology over time. The investigators hypothesize measures relating to mental performance and health will improve after 4-weeks of CWI, and there will be no difference between tub and shower immersion groups.

Trial Health

55
Monitor

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Trial has exceeded expected completion date
Enrollment
75

participants targeted

Target at P50-P75 for not_applicable

Timeline
Completed

Started Oct 2024

Geographic Reach
1 country

1 active site

Status
enrolling by invitation

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

October 10, 2024

Completed
Same day until next milestone

Study Start

First participant enrolled

October 10, 2024

Completed
21 days until next milestone

First Posted

Study publicly available on registry

October 31, 2024

Completed
10 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

September 1, 2025

Completed
1 month until next milestone

Study Completion

Last participant's last visit for all outcomes

October 1, 2025

Completed
Last Updated

October 31, 2024

Status Verified

October 1, 2024

Enrollment Period

11 months

First QC Date

October 10, 2024

Last Update Submit

October 29, 2024

Conditions

Keywords

Cold Water ImmersionCold TubCold Shower

Outcome Measures

Primary Outcomes (11)

  • Sustained Attention to Response Task (SART)

    The SART is a task used to evaluate sustained attention and inhibitory control. Participants will complete the SART task on a laboratory computer. The computerized test will display 225 randomly selected numbers ranging between 1 and 9; these numbers appear in different sizes throughout the duration of the test and are displayed in white on a black screen. Participants will be instructed to respond when each number appears by pressing the space bar on the computer's keyboard while refraining from pressing the space bar when the number 3 appears. Total error score will be calculated by assessing the number of space bar presses when no key should've been pressed as well as absent presses when a key should've been pressed.

    Visit 1B (Week 1) and Visit 2B (Week 4)

  • Alternate Use Task (AUT)

    The Alternate Use Task is used to evaluate creativity and divergent thinking. The task will be derived from the original paper version of the AUT, in which an everyday object will be randomly selected and presented to the participant, and the participant will be tasked with thinking of a possible use for the presented object. Participants will be instructed to think of novel and unique uses that would deviate from traditional uses of the presented object. Participants will be given a blank sheet of paper and be granted 2-minutes to write down as many uses as possible. In this modified version of the original test, participants will be screened for originality, fluency, and flexibility.

    Visit 1B (Week 1) and Visit 2B (Week 4)

  • Piper Fatigue Scale (PFS)

    Participants will be asked to complete the Piper Fatigue Scale (PFS), a 27-question questionnaire that utilizes a Likert scale (1-10) to assess subdomains of behavioral, affective, sensory, and cognitive/mood attributes of fatigue. This version of the PFS is a subjective measure of fatigue using a 10-point Likert scale ranging from 0 - 10 with 0 indicating "No Distress" and 10 indicating "A Great Deal", "Mild" to "Severe", "Pleasant" to "Unpleasant", "Agreeable" to "Disagreeable", "Protective" to "Destructive", "Positive" to "Negative", "Normal" to "Abnormal", "Strong" to "Weak", "Awake" to "Sleepy", "Lively" to "Listless", "Refreshed" to "Tired", "Energetic" to "Unenergetic", "Patient" to "Impatient", "Relaxed" to "A Great Deal", "Exhilarated" to "Depressed", "Able to Concentrate" to "Unable to Concentrate", "Able to Remember" to "Unable to Remember", and "Able to Think Clearly" to "Unable to Think Clearly".

    Visit 1B (Week 1) and Visit 2B (Week 4)

  • Perceived Stress Scale (PSS)

    Participants will be asked to complete the Perceived Stress Scale (PSS), a classic stress assessment tool used to gauge how different situations affect feelings and perceived stress. This version of the PSS is a subjective measure of stress using a 5-point Likert scale ranging from 0 - 4 with 0 indicating "Never", 1 indicating "Almost Never", 2 indicating "Sometimes", 3 indicating "Fairly Often", and 4 indicating "Very Often".

    Visit 1B (Week 1) and Visit 2B (Week 4)

  • Mindful Attention Awareness Scale (MAAS)

    Participants will be asked to complete the Mindful Attention Awareness Scale (MAAS), a 15-item scale designed to assess the core characteristics of mindfulness. This version of the MAAS is a subjective measure of mindfulness using a 6-point Likert scale ranging from 1 - 6 with 1 indicating "Almost Always", 2 indicating "Very Frequently", 3 indicating "Somewhat Frequently", 4 indicating "Somewhat Infrequently", 5 indicating "Very Infrequently", and 6 indicating "Almost Never".

    Visit 1B (Week 1) and Visit 2B (Week 4)

  • Heart Rate Variability (HRV)

    Heart rate variability (HRV) will be analyzed to determine the fluctuation in the time intervals between adjacent heartbeats to assess autonomic regulation of the heart. Resting HR and HRV were measured using the electrocardiograph (GE CASE Exercise Testing System Version 6.0, Chicago, Illinois). To measure HRV, the root mean square successive difference method (RMSSD) was used with the 10-second electrocardiogram reading. Based on the outcome of this assessment, participants with SDNN values below 50 ms will be classified as unhealthy, 50-100 ms will be classified as having compromised health, and above 100 ms will be classified as healthy.

    Visit 1B (Week 1) and Visit 2B (Week 4)

  • 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 is run again. Three sets will be completed for this test, and the highest value (kg) is recorded for analysis.

    Visit 1B (Week 1) and Visit 2B (Week 4)

  • Pittsburgh Sleep Quality Index (PSQI)

    Participants will be asked to complete the Pittsburgh Sleep Quality Index (PSQI). The PSQI is a 19-question self-reported sleep quality screening 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.

    Visit 1A (Week 1) and Visit 2A (Week 4)

  • Serum Analysis - Brain-Derived Neurotrophic Factor (BDNF)

    Approximately 40mL of whole blood will be collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA), allowed to clot for 30-minutes 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 BDNF (Sigma-Aldrich, St. Louis, MO, USA) will be determined with a commercially available enzyme-linked immunosorbent assays. 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)

  • Serum Analysis - Cortisol

    Approximately 40mL of whole blood will be collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA), allowed to clot for 30-minutes 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 cortisol (ALPCO Diagnostics, Salem, NH, USA) will be determined with a commercially available enzyme-linked immunosorbent assays. 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)

  • Serum Analysis - Nerve Growth Factor (NGF)

    Approximately 40mL of whole blood will be collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA), allowed to clot for 30-minutes 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 NGF (RayBiotech, Norcross, GA, USA) will be determined with a commercially available enzyme-linked immunosorbent assays. 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)

Secondary Outcomes (7)

  • Anthropometric Measures - Height

    Visit 1A (Week 1) and Visit 2A (Week 4)

  • Anthropometric Measures - Weight

    Visit 1A (Week 1) and Visit 2A (Week 4)

  • Anthropometric Measures - Lean Body Mass

    Visit 1A (Week 1) and Visit 2A (Week 4)

  • Anthropometric Measures - Body Fat Percentage

    Visit 1A (Week 1) and Visit 2A (Week 4)

  • Hydration

    Visit 1A (Week 1) and Visit 2A (Week 4)

  • +2 more secondary outcomes

Study Arms (3)

Cold Tub Immersion Group (CI)

EXPERIMENTAL

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

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

Control Group (CO)

NO INTERVENTION

Participants will not participate in any cold water immersion.

Interventions

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)

Once thermoneutral procedures are complete, participants in the CS group will be instructed to enter the research shower area in Gunter 1610. 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 three 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

Age18 Years - 45 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

  • Healthy volunteers
  • Aged 18-45

You may not qualify if:

  • Current holds a cold water exposure routine (≥3 sessions in the last month, consisting of ≥4 minutes per immersion)
  • Currently pregnant of planning to become pregnant
  • Chronic use of anti-inflammatory medication
  • Prior history of chronic disease conditions: Cardiovascular Disease, Diabetes, Cancer, Raynaud's Disease, or severe/untreated anxiety or depression

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

University of Northern Colorado

Greeley, Colorado, 80639, United States

Location

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
OTHER
Intervention Model
PARALLEL
Model Details: Parallel, randomized design, matched for biological age
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Professor

Study Record Dates

First Submitted

October 10, 2024

First Posted

October 31, 2024

Study Start

October 10, 2024

Primary Completion

September 1, 2025

Study Completion

October 1, 2025

Last Updated

October 31, 2024

Record last verified: 2024-10

Data Sharing

IPD Sharing
Will share

We will make all study documents available by reasonable request (Laura.stewart@unco.edu) up to 3 years after data collection is complete.

Time Frame
Start: Oct 1, 2025 - Oct 1, 2028
Access Criteria
Anyone who contacts Laura.stewart@unco.edu with a reasonable request.

Locations