Trial Outcomes & Findings for The Effect of Cold Water Immersion on Recovery and Performance in NCAA Division I Athletes (NCT NCT06565468)
NCT ID: NCT06565468
Last Updated: 2026-08-04
Results Overview
As measured by WHOOP 4.0 wrist device.
COMPLETED
NA
75 participants
Four week time period
2026-08-04
Participant Flow
Rolling enrollment occurred across fall 2024 and spring 2025 team cohorts at UCLA.
The final audited crossover schedule used for results included 60 athletes with participant specific CWI and control windows, with 20 assigned CWI first and 40 assigned control first. Participants without confirmed schedule windows or usable final outcome linkage were excluded from paired outcome analyses. Denominators are outcome specific.
Participant milestones
| Measure |
CWI-first Sequence
Participants assigned to begin with scheduled cold water immersion windows followed by control windows in the participant-specific crossover schedule.
|
Control-first Sequence
Participants assigned to begin with control windows followed by scheduled cold water immersion windows in the participant-specific crossover schedule.
|
|---|---|---|
|
Overall Study
STARTED
|
20
|
40
|
|
Overall Study
COMPLETED
|
20
|
40
|
|
Overall Study
NOT COMPLETED
|
0
|
0
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
Race and Ethnicity were not collected from any participant.
Baseline characteristics by cohort
| Measure |
CWI-first Sequence
n=20 Participants
Participants assigned to begin with scheduled cold water immersion windows followed by control windows in the participant-specific crossover schedule.
|
Control-first Sequence
n=40 Participants
Participants assigned to begin with control windows followed by scheduled cold water immersion windows in the participant-specific crossover schedule.
|
Total
n=60 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Categorical
<=18 years
|
1 Participants
n=20 Participants
|
0 Participants
n=40 Participants
|
1 Participants
n=60 Participants
|
|
Age, Categorical
Between 18 and 65 years
|
19 Participants
n=20 Participants
|
40 Participants
n=40 Participants
|
59 Participants
n=60 Participants
|
|
Age, Categorical
>=65 years
|
0 Participants
n=20 Participants
|
0 Participants
n=40 Participants
|
0 Participants
n=60 Participants
|
|
Sex: Female, Male
Female
|
8 Participants
n=20 Participants
|
18 Participants
n=40 Participants
|
26 Participants
n=60 Participants
|
|
Sex: Female, Male
Male
|
12 Participants
n=20 Participants
|
22 Participants
n=40 Participants
|
34 Participants
n=60 Participants
|
|
Race and Ethnicity Not Collected
|
—
|
—
|
0 Participants
Race and Ethnicity were not collected from any participant.
|
|
Region of Enrollment
United States
|
20 participants
n=20 Participants
|
40 participants
n=40 Participants
|
60 participants
n=60 Participants
|
PRIMARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 WHOOP data in both cold water immersion and control conditions for this outcome.
As measured by WHOOP 4.0 wrist device.
Outcome measures
| Measure |
Cold Water Immersion
n=58 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=58 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Heart-rate Variability
|
96.627 milliseconds
Standard Deviation 36.067
|
95.272 milliseconds
Standard Deviation 36.555
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 WHOOP data in both cold water immersion and control conditions for this outcome.
As measured by WHOOP 4.0 wrist device.
Outcome measures
| Measure |
Cold Water Immersion
n=58 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=58 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Resting Heart Rate
|
51.507 beats per minute
Standard Deviation 8.287
|
51.947 beats per minute
Standard Deviation 8.135
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 WHOOP data in both cold water immersion and control conditions for this outcome.
Total sleep time measured by WHOOP 4.0 wrist device and reported in minutes.
Outcome measures
| Measure |
Cold Water Immersion
n=58 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=58 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Total Sleep Time
|
395.401 minutes/night
Standard Deviation 64.419
|
404.132 minutes/night
Standard Deviation 50.216
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 WHOOP data in both cold water immersion and control conditions for this outcome.
Slow-wave sleep time measured by WHOOP 4.0 wrist device and reported in minutes.
Outcome measures
| Measure |
Cold Water Immersion
n=58 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=58 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Slow Wave Sleep Time
|
88.702 minutes/night
Standard Deviation 23.439
|
89.035 minutes/night
Standard Deviation 23.472
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 WHOOP data in both cold water immersion and control conditions for this outcome.
WHOOP Sleep Consistency score on a 0 to 100 scale; higher scores indicate more consistent sleep timing.
Outcome measures
| Measure |
Cold Water Immersion
n=58 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=58 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Sleep Consistency
|
65.328 score on 0-100 scale
Standard Deviation 10.460
|
62.041 score on 0-100 scale
Standard Deviation 9.257
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 REDCap survey data in both cold water immersion and control conditions for this outcome.
Lower-extremity muscle soreness on a 0 to 6 Likert scale; higher scores indicate greater soreness and worse symptoms.
Outcome measures
| Measure |
Cold Water Immersion
n=54 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=54 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Likert Scale of Muscle Soreness
|
2.272 score on 0-6 scale
Standard Deviation 1.007
|
2.323 score on 0-6 scale
Standard Deviation 1.018
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 REDCap survey data in both cold water immersion and control conditions for this outcome.
Total Quality Recovery scale from 6 to 20; higher scores indicate better perceived recovery.
Outcome measures
| Measure |
Cold Water Immersion
n=54 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=54 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Total Quality Recovery Scale
|
14.464 score on 6-20 scale
Standard Deviation 1.716
|
14.476 score on 6-20 scale
Standard Deviation 1.299
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired participants with final June 2026 REDCap survey data in both cold water immersion and control conditions for this outcome.
Single Item Sleep Quality scale from 0 to 10; higher scores indicate better perceived sleep quality.
Outcome measures
| Measure |
Cold Water Immersion
n=54 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=54 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Single Item Sleep Questionnaire
|
6.513 score on 0-10 scale
Standard Deviation 1.352
|
6.445 score on 0-10 scale
Standard Deviation 1.078
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired athletes with final June 2026 ForceDecks counter-movement jump data mapped to both cold water immersion and control windows.
Countermovement jump height measured with ForceDecks and reported in inches using the flight-time method; higher values indicate better jump performance.
Outcome measures
| Measure |
Cold Water Immersion
n=51 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=51 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Counter Movement Jump
|
14.530 inches
Standard Deviation 3.336
|
14.467 inches
Standard Deviation 3.514
|
SECONDARY outcome
Timeframe: Four week time periodPopulation: Paired athletes with final June 2026 ForceDecks drop-jump data mapped to both cold water immersion and control windows.
Drop-jump reactive strength index calculated as flight time divided by contact time from ForceDecks; higher values indicate better reactive jump performance.
Outcome measures
| Measure |
Cold Water Immersion
n=39 Participants
Outcomes measured during the cold water immersion condition. CWI consisted of 10 minutes of cold water immersion at approximately 53 degrees F within 1 hour after training during assigned CWI weeks.
|
Control/Baseline
n=39 Participants
Outcomes measured during the control or baseline comparison condition without cold water immersion.
|
|---|---|---|
|
Drop Jump
|
1.633 ratio
Standard Deviation 0.431
|
1.656 ratio
Standard Deviation 0.437
|
Adverse Events
Cold Water Immersion
Control
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Joshua T. Goldman, MD, MBA
University of California, Los Angeles
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place