Clinical trial NCT06908447: Cold Water and Decision-Making
Official title: Voluntary Cold-Water Immersion Effects on Value-Based Choice
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: Behavior
Stress
Quality of Life
Psychological Wellbeing
Keywords: Decision-Making
Psychology
Stress
Cold-Exposure
Cold-Water Immersion
Lead sponsor: German Institute of Human Nutrition
Sponsor class: OTHER
First posted: 2025-04-03
Enrollment: 40
Sex: ALL
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: The behavioral within-subject cross-over design study "CoVa" aims to investigate the effect of a short-term full-body cold-water immersion vs. warm-water immersion control on value-based choice, psychological well-being, and peripheral physiology.

Detailed description: This randomized within-subject cross-over design behavioral study in cognitive neuroscience will employ an acute peripheral physiological intervention, i.e., a 10-minute full-body cold-water (10-16°C) immersion vs. a control condition (10 min @ 30- 36°C water) on two visits separated by approx. 30 days.

Forty eligible female and male participants will be subject to a head-out full-body cold-water immersion or a warm-water condition (control) on two visits. Participants will perform resting-state and task-based non-invasive electrophysiological recordings of the heart, pulse, respiration, skin conductance, and pupil, will undergo thermographic imaging, pre- and post-immersion blood sampling (4 time points), engage in two computer-based decision-making tasks (reinforcement learning task, risk decision-making task), a brief food choice task, and receive a battery of psychometric questionnaires. The visits are separated by approximately 30 days and do not differ in their timeline except for the primary intervention, i.e., cold vs warm-water immersion, and the medical screening on visit 1.

Eligibility criteria: Inclusion Criteria:

* 18-40 years of age
* Consent to participate
* Fluency in German
* Physically and mentally healthy
* BMI 18-30 kg/m2
* Normal day-night rhythm

Exclusion Criteria:

* Raynaud syndrome
* Cold urticaria
* High resting heart rate (\>160 beats per minute)
* Acute infection
* Diagnosed current or former illnesses of

  * Brain and mind
  * Heart and blood circulation
  * Gastrointestinal system
  * Endocrine system
  * Other serious past or present medical conditions
* Wearing of medical devices (e.g., pacemaker)
* Fear of blood, needles, or phlebotomy
* Allergies to plasters, gels, and other medical equipment
* Allergies to commercially available liquid meals (e.g., shakes, yfood Labs GmbH)
* Recurrent intake of medication which affect metabolism
* Regular nicotine consumption (e.g., vaping, cigarettes)
* Excessive alcohol consumption (\>14 servings/week)
* Recent illegal drug consumption (within 2 weeks prior)
* Strong mental or physical stress
* Excessive exercise (\>2 h high-intensity exercise/day)
* Pregnancy or breastfeeding
* Inability to wear skin-exposing swimwear, e.g., for religious reasons
* Affinity for winter swimming, cryotherapy, breathwork (\>3 times/year)

Primary outcomes:
measure: Risk propensity
timeFrame: On day 1 and after 30 days
measure: Behavioral range adaptation
timeFrame: On day 1 and after 30 days
measure: Food choice
timeFrame: On day 1 and after 30 days
measure: Heart-rate variability
timeFrame: On day 1 and after 30 days
measure: Heart rate
timeFrame: On day 1 and after 30 days
measure: Respiration rate
timeFrame: On day 1 and after 30 days
measure: Relative amplitude of the respiratory signal
timeFrame: On day 1 and after 30 days
measure: Event-related skin conductance responses
timeFrame: On day 1 and after 30 days
measure: Tonic skin conductance
timeFrame: On day 1 and after 30 days
measure: Pupil dilation
timeFrame: On day 1 and after 30 days
measure: Skin temperature
timeFrame: On day 1 and after 30 days
measure: Plasma concentration of large neutral amino acids
timeFrame: On day 1 and after 30 days
measure: Plasma concentration of catecholamines
timeFrame: On day 1 and after 30 days
measure: Plasma concentration of cortisol
timeFrame: On day 1 and after 30 days
measure: Identification of epigenetic markers associated with acute cold exposure
timeFrame: On day 1 and after 30 days
measure: Perceived control
timeFrame: On day 1 and after 30 days
measure: Perceived freedom
timeFrame: On day 1 and after 30 days
measure: Perceived stress
timeFrame: On day 1 and after 30 days
measure: State of flow
timeFrame: On day 1 and after 30 days
measure: Self-efficacy
timeFrame: On day 1 and after 30 days
measure: Perceived pain
timeFrame: On day 1 and after 30 days
measure: Emotions
timeFrame: On day 1 and after 30 days
measure: Positive affect and negative affect questionnaire
timeFrame: On day 1 and after 30 days
Secondary outcomes:
measure: Trait autonomy questionnaire
timeFrame: On day 1 and after 30 days
measure: Emotion regulation questionnaire
timeFrame: On day 1 and after 30 days
measure: Causality orientation questionnaire
timeFrame: On day 1 and after 30 days
measure: Delay discounting questionnaire
timeFrame: On day 1 and after 30 days
measure: Interoceptive awareness questionnaire
timeFrame: On day 1 and after 30 days
measure: Generalized self-efficacy questionnaire
timeFrame: On day 1 and after 30 days
measure: Trait and state anxiety questionnaire
timeFrame: On day 1 and after 30 days
measure: Well-being questionnaire
timeFrame: On day 1 and after 30 days
Other outcomes:
Locations:
city: Nuthetal
country: Germany
facility: German Institute of Human Nutrition Potsdam-Rehbruecke
Study officials:
affiliation: German Institute of Human Nutrition Potsdam-Rehbruecke
name: Soyoung Q Park, Prof. Dr.
role: PRINCIPAL_INVESTIGATOR
References: