Voluntary Cold-Water Immersion Effects on Value-Based Choice
Trial Snapshot
- Phase
- Not Applicable
- Status
- Recruiting
- Enrollment
- 40
- Locations
- 1
- Primary Endpoint
- Risk propensity
Study Overview
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to 40 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
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)
Arms & Interventions
Warm-water immersion (Control)
Intervention: Warm-water immersion (Control) (Behavioral)
Cold-water immersion
Intervention: Cold-water immersion (Behavioral)
Outcomes
Primary Outcomes
Risk propensity
Time Frame: On day 1 and after 30 days
Risk propensity, i.e., the ratio between risky and non-risky choices for each monetary value as measured in the risk decision-making task in the cold-water vs warm-water condition as described in Liu et al. (2021)
Behavioral range adaptation
Time Frame: On day 1 and after 30 days
Participants will perform a computer-based reinforcement learning task described in Gueguen et al. (2024) to assess reward sensitivity in different monetary contexts. Behavioral range adaptation, which reflects value range-dependent, relative reward valuation, may be altered if reward processing itself is changed through a potent shift in the physiological state. To test whether reward processing is altered after cold vs warm water exposure, the extent to which range adaptation and reference-point centering occurs will be quantified using computational modeling methods.
Food choice
Time Frame: On day 1 and after 30 days
Participants will be provided an ad libitum restaurant-like breakfast meal during which they can order various food items (e.g., bread, yogurts, cookies) in the desired amount. The ingested food type, nutritional value, and amount will be quantified to assess food preference after cold vs warm water exposure by linking the consumed food with a standardized food database (German Nutrient Database, Bundeslebensmittelschlüssel).
Heart-rate variability
Time Frame: On day 1 and after 30 days
Task-based and resting-state heart-rate variability, measured with a three-point electrocardiogram (ECG)
Heart rate
Time Frame: On day 1 and after 30 days
Task-based and resting-state heart rate, measured with ECG
Respiration rate
Time Frame: On day 1 and after 30 days
Task-based and resting-state respiration rate, measured via a respiration belt
Relative amplitude of the respiratory signal
Time Frame: On day 1 and after 30 days
Task-based and resting-state relative respiratory amplitude, measured via a respiratory belt
Event-related skin conductance responses
Time Frame: On day 1 and after 30 days
Phasic electrodermal activity, measured via electrodermal activity (EDA) electrodes
Tonic skin conductance
Time Frame: On day 1 and after 30 days
Tonic task-based and resting-state electrodermal activity, measured with EDA electrodes
Pupil dilation
Time Frame: On day 1 and after 30 days
Task-based and resting-state pupil dilation, measured via eye-tracking
Skin temperature
Time Frame: On day 1 and after 30 days
Thermographic imaging of the face, full-body, supraclavicular, and scapular area using a thermal camera pre-, during, and post-immersion
Plasma concentration of large neutral amino acids
Time Frame: On day 1 and after 30 days
Large neutral amino acid (LNAA) plasma concentration will be assessed via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)
Self-efficacy
Time Frame: On day 1 and after 30 days
Psychological changes in self-efficacy, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high self-efficacy.
Plasma concentration of catecholamines
Time Frame: On day 1 and after 30 days
Catecholamines via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)
Plasma concentration of cortisol
Time Frame: On day 1 and after 30 days
Cortisol via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)
Identification of epigenetic markers associated with acute cold exposure
Time Frame: On day 1 and after 30 days
Epigenetic markers (micro-RNA) via blood sampling at 4 time points (pre-immersion to 120 min post-immersion)
Perceived control
Time Frame: On day 1 and after 30 days
Psychological changes in perceived control, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived control.
Perceived freedom
Time Frame: On day 1 and after 30 days
Psychological changes in perceived freedom, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived freedom.
Perceived stress
Time Frame: On day 1 and after 30 days
Psychological changes in perceived stress, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived stress.
State of flow
Time Frame: On day 1 and after 30 days
Psychological changes in perceived state of flow, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating a high state of flow.
Perceived pain
Time Frame: On day 1 and after 30 days
Psychological changes in perceived pain, measured semi-continuously via self-reports throughout the experimental day. Measures range from 0% (not at all) to 100% (very much) with 100% indicating high perceived pain.
Emotions
Time Frame: On day 1 and after 30 days
Psychological changes in emotions and their bodily origins, measured via self-reports pre- and post-immersion. Measures will be drawn on a virtual body using an adapted version of the Nummenmaa et al. (2014) emBODY tool with red color indicating increased perception and blue indicating decreased perception.
Positive affect and negative affect questionnaire
Time Frame: On day 1 and after 30 days
Psychological changes in affect, measured semi-continuously via the Positive Affect Negative Affect (PANAS) questionnaire to be filled out pre- and post-immersion. Measures for each item range from 1 (not at all) to 5 (very much) with 5 indicating the highest feeling perceived at the moment.
Secondary Outcomes
- Trait autonomy questionnaire(On day 1 and after 30 days)
- Emotion regulation questionnaire(On day 1 and after 30 days)
- Causality orientation questionnaire(On day 1 and after 30 days)
- Delay discounting questionnaire(On day 1 and after 30 days)
- Interoceptive awareness questionnaire(On day 1 and after 30 days)
- Generalized self-efficacy questionnaire(On day 1 and after 30 days)
- Trait and state anxiety questionnaire(On day 1 and after 30 days)
- Well-being questionnaire(On day 1 and after 30 days)
Investigators
Prof. Dr. Soyoung Q Park
Prof. Dr.
German Institute of Human Nutrition