NCT06667479

Cold Water Exposure and Immune Function Study

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

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 37 (actual)
• Sponsor: University of Northern Colorado · Academic / Other
• Sex: All
• Age: 18 Years – 45 Years
• Healthy volunteers: Accepted

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

Interventions

Type	Name	Description
OTHER	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 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	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.

Timeline

• Start date: 2024-10-10
• Primary completion: 2026-02-01
• Completion: 2026-03-01
• First posted: 2024-10-31
• Last updated: 2026-03-10

Locations

1 site across 1 country: United States