Overview
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.
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
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)