Thermodynamic Exposure and Sleep in Military Cadets

Not Applicable

Not yet recruiting

• Conditions: Cold-water Immersion; High Heat Sauna; Combination of Cold-water Immersion and High Heat Sauna

• Registration Number: NCT07201935
• Lead Sponsor: Medical University of South Carolina

Brief Summary

This pilot study investigates the effects of cold-water immersion, traditional sauna use, and their combination on sleep architecture, glymphatic clearance, and psycho-affective health in military cadets. The study uses wearable technologies including the Oura Ring and the Applied Cognition Glymphatic Monitor to collect objective sleep and physiological data.

Detailed Description

The study will enroll 45 military cadets from The Citadel Military College, randomized into three groups: Cold-Water Immersion (CWI), High Heat Sauna (HHS), and Combined (COM). Participants will undergo a 7-day baseline period followed by a 14-day intervention. Sleep architecture, glymphatic function, and psycho-affective health will be assessed using validated wearable devices and questionnaires. The study aims to identify intervention-specific improvements in sleep and glymphatic clearance.

Study Timeline

• Status Verified: 2025-09
• Study First Submitted: 2025-09-12
• Study First Submitted QC: 2025-09-23
• Last Update Submitted: 2025-09-23
• Study Start: 2025-10-01
• Study First Posted: 2025-10-01
• Last Update Posted: 2025-10-01
• Primary Completion: 2026-10
• Study Completion: 2026-10-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 45

Inclusion Criteria

• 18 - 30 years of age
• Member of the Ranger Challenge group at The Citadel.
• Access to a smartphone with access to appropriate app marketplace (Apple iOS 15, Android 8.0 or newer) and reliable data access.
• Ability to access and operate Oura Ring application

Exclusion Criteria

• Medical contraindications to continuous wearing of the Oura Ring.
• Current diagnosis of neurological, cardiovascular, and/or sleep disorder.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Glymphatic clearance	End of baseline monitoring phase (Day 7), end of intervention week 1 (Day 14), and end of intervention (Day 28)	Changes in parenchymal resistance during sleep
Sleep Efficiency	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Percentage of sleep period spent asleep measured by the Oura Ring (percentage, %)
Pittsburgh Sleep Quality Index	At the end of the baseline monitoring phase (Day 7), end of intervention week 1 (Day 14), and end of intervention phase (Day 28)	Self-reported sleep quality
Profile of Mood States: Total Mood Disturbance	At the end of the baseline monitoring phase (Day 7), end of intervention week 1 (Day 14), and end of intervention phase (Day 28)	Self-reported mood disturbance used by summing all negative profiled mood sub-scores (tension, depression, anger/hostility, fatigue, and confusion) and subtracting the positive profiled mood sub-score (vigor). (score -32 - 200, higher equals greater mood disturbance)

Secondary Outcome Measures

Name	Time	Method
REM Sleep Duration	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Duration of sleep period spent in REM sleep measured by the Oura Ring (seconds, s)
Deep Sleep Duration	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Duration of sleep periods spent in deep (N3) sleep (seconds, s)
Total Sleep Duration	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Total duration of sleep period measured by the Oura Ring (seconds, s)
Light Sleep Duration	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Duration of sleep period spent in light (N1 or N2) sleep (seconds, s)
Profile of Mood States: Confusion	End of baseline monitoring period (Day 7), end of intervention week 1 (Day 14), and end of intervention (Day 28)	Confusion sub-score from the POMS (score 0 - 28, higher equals more confusion)
Wake After Sleep Onset (WASO) Duration	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Total time spent awake after falling asleep (seconds, s)
Profile of Mood States: Tension/Anxiety	End of baseline monitoring period (Day 7), end of intervention week 1 (Day 14), and end of intervention (Day 28).	Tension/Anxiety sub-score computed from the POMS (score 0 - 36, higher equals more tension/anxiety)
Restless Sleep Duration	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Duration of sleep period with increased registered movements as measured by the Oura Ring (seconds, s)
RMSSD	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Root mean squared of temporal latency between successive heart beats throughout sleep period measured by the Oura Ring (milliseconds, ms)
Nighttime Skin Temperature	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Skin temperature (degrees Celsius, C°) throughout sleep period measured by the Oura Ring.
Sleep Time Heart Rate	Each night of the baseline monitoring period (7days) and intervention phase (14days)	Average heart rate during sleep (beats per minute, bpm)
Profile of Mood States: Depression	End of baseline monitoring period (Day 7), end of intervention week 1 (Day 14), and end of intervention (Day 28)	Depression sub-score from the POMS (score 0 - 60, higher equals greater depression)
Profile of Mood States: Anger/Hostility	End of baseline monitoring period (Day 7), end of intervention week 1 (Day 14), and end of intervention (Day 28)	Anger/Hostility sub-score from the POMS (score 0 - 48, higher equals greater anger/hostility)
Profile of Mood States: Vigor	End of baseline monitoring period (Day 7), end of intervention week 1 (Day 14), and end of intervention (Day 28)	Vigor sub-score from the POMS (score 0 - 32, higher equals more vigor)
Profile of Mood States: Fatigue	End of baseline monitoring period (Day 7), end of intervention week 1 (Day 14), and end of intervention (Day 28)	Fatigue sub-score from the POMS (score 0 - 28, higher equals more fatigue)

Trial Locations

Locations (1)

The Citadel Military College; 🇺🇸 Charleston, South Carolina, United States