Breathing and Decision-Making (ProlEx-Context) | NCT07505641

NCT07505641

Protocol Section

Identification Module

Results Section

No data available

No data is available for this block.

Annotation Section

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No data is available for this block.

Document Section

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No data is available for this block.

Derived Section

Miscellaneous Info Module

ID	Type	Description	Link
88/2025 107/2025	Other Identifier	Ethics Committee of the University of Potsdam

Status Module

Description Module

Detailed Description

The ProlEx-Context study explores how a slow breathing technique with prolonged exhalation can restore decision-making processes after exposure to acute social stress.

Method Overview:

The methods of the study include a guided breathing exercise (prolonged exhalation vs normal breathing rhythm), exposure to acute social stress, peripheral electrophysiology (respiration, pulse, gastric and cardiac rhythms, skin conductance, pupillometry), salivary cortisol sampling, psychological questionnaires, behavioral tasks and functional brain imaging with fMRI.

Participant Overview:

An estimated 50 participants will be invited to this within-subject fMRI study and will be blinded to the stress induction component of this study.

Time frame:

One appointment of approx. 4 hours per person.

Procedure Overview:

Participants will be invited to the testing site at approximately 4 PM. Upon completion of the preparations and placement inside the MRI, the participants will undergo an adapted virtual Trier Social Stress Test (TSST). After completing the TSST, the participants are asked to perform a risk decision-making task inside the MRI, during which they are displayed a visual cue to assist during guided breathing. The participants perform blocks of either normal breathing or prolonged exhalation breathing during performance of the decision-making task in a randomized cross-over-design. During the task, brain activity and peripheral physiological signals, such as the respiration rate, heart rate, skin conductance and pupil dilation are measured. After completion of the first breathing condition (three blocks) and before the second breathing condition, participants will undergo a second TSST. Before and after each TSST, at baseline and after completion of the decision-making task, salivary samples for cortisol assessment are taken. After completion of the decision-making task, participants will be asked to fill out a battery of psychometric questionnaires and reimbursed for their time.

Arms/Interventions Module

Arm Groups

Label	Type	Description	Intervention Names
Prolonged Exhalation Breathing	Experimental	Participants are required to perform a specific voluntarily controlled breathing pattern directed by visual cues. The core characteristic is a systematic lengthening of the expiratory phase relative to the inspiratory phase. Specifically, participants are instructed to inhale for 2 seconds and prolong their exhalation to 8 seconds	Behavioral: Instructed Prolonged Exhalation
Eupnea Breathing (Normal)	Experimental	Eupnea (Normal breathing) condition: In this control condition, participants maintain their spontaneous respiratory rhythm. The pacing for eupnea is individualized for each participant, based on their natural breathing frequency sampled during representative non-interventional intervals of the session (e.g., baseline or post-stress recovery periods). This ensures the control condition reflects the participant's characteristic physiological state within the experimental context.	Behavioral: Instructed Individualized Eupnea

Interventions

Name	Type	Description	Arm Group Labels	Other Names
Instructed Prolonged Exhalation	Behavioral	Participants are required to perform a specific instructed breathing pattern directed by visual cues. The core characteristic is a systematic lengthening of the expiratory phase relative to the inspiratory phase. Specifically, participants are instructed to inhale for 2 seconds and prolong their exhalation to 8 seconds.

Outcomes Module

Primary Outcomes

Measure	Description	Time Frame
Risk propensity	The dependent variable will be trial-wise gamble acceptance (accept vs. reject of a 50% gamble), which will be mainly analyzed using a binomial generalized linear mixed-effects model (GLMM) to compare the Prolonged Exhalation and Eupnea conditions under acute stress.	On day 1.
Task-related BOLD Signals	Task-related changes in blood-oxygen-level-dependent (BOLD) signals measured using functional magnetic resonance imaging (fMRI).	On day 1.
Structural T1-weighted MRI	High-resolution T1-weighted structural images measured using magnetic resonance imaging (MRI).	On day 1.
Relative amplitude of the respiratory signal	Task-based and resting-state relative respiratory amplitude, measured via a respiratory belt and nasal airflow sensor.	On day 1.
Respiration rate	Task-based and resting-state relative respiratory amplitude, measured via a respiratory belt and nasal airflow sensor.	On day 1.
Heart rate	Task-based and resting-state heart rate, measured with ECG	On day 1.
Heart-rate variability	Task-based and resting-state heart-rate variability, measured with a three-point electrocardiogram (ECG)	On day 1.

Secondary Outcomes

Measure	Description	Time Frame
Response Times	The average time (in milliseconds) taken by participants to make a choice in each trial.	On day 1.
Self-reported levels of stress	Self-reported levels of stress will be measured via a Visual Analog Scale (VAS) ranging from 0 to 100. A score of 0 represents "not at all" and 100 represents "extremely high."

Eligibility Module

Eligibility Criteria

Inclusion Criteria:

18- to 40-year-old men and women
Consent to participate
Fluent in German
Right-handed
Physically and mentally healthy without regular medication
Body-mass index of 18-25 kg/m2
Alcohol consumption of less than 15 glasses a week (equivalent to one glass of wine/beer, a glass of higher-percentage alcohol counts as two glasses of beer)
No illegal drug consumption in the week previous to the experiment
No smoking
No competitive athletes
Normal day-night rhythm (no shift work)
Normal vision without required vision correction (i.e., glasses, contact lenses; ability to clearly read texts at a distance of up to 50 cm without vision aids)

Exclusion Criteria:

Former or current illnesses of:
Brain or mind (including anxiety disorders, depression, eating disorders, personality disorders, alcohol, drugs or drug dependence, neurological disorders other than occasional headache, psychiatric or neurological abnormalities)
Heart or blood circulation
Lung Diseases
Other serious past or present medical conditions (for example, metabolic syndrome, diabetes)
Current medication and medication over a period of two weeks prior to the examination
Other serious health problems or present strong mental or physical stress
Current infection or excessive stress
Missing consent to receive information about incidental findings from the MRI
Tendency to claustrophobia, dizziness, or panic attacks
Wearing a non-removable pacemaker, defibrillator, hearing aid, drug pump, neurostimulator or implant with solenoid valve (e.g., artificial bowel outlet)
Metal parts or implants inside the body, for example, due to surgery or injury with a metallic foreign object (e.g., hip replacements, artificial joints, heart valves, vessel occlusions or dilatations, surgical clips, bone screws or plates, coil, shunts, catheters, electrodes, coils, radiation sources, shrapnel, projectiles, stents)
Having non-removable metal parts or metal-containing devices on or in the body
Having ferromagnetic metal parts or implants inside the body (e.g., hip replacements, artificial joints, heart valves, vessel occlusions or dilatations, surgical clips, bone screws or plates, coils, shunts, catheters, electrodes, coils, radiation sources, shrapnel, projectiles, stents)
Wearing magnetically fixed implants (e.g. amalgam fillings, glass eye)
Professionally or privately being involved in the processing of ferromagnetic metals
Large tattoos (whole limbs)
Pregnancy
Wearing an intra-uterine device
Having tinnitus
Extensive lung function (e.g. apnoe diver, singer, professional musician with lung-involving instruments)
Previous participation in the ProlEx-MRI study (the precursor to the current study)

Name	Role	Phone	Extension	Email
Soyoung Q Park, Prof. Dr.	Contact	+49 033200 88 2510		soyoung.park@dife.de
Wenhao Huang	Contact			Wenhao.Huang@dife.de

Name	Affiliation	Role
Soyoung Q Park, Prof. Dr.	German Institute of Human Nutrition Potsdam-Rehbruecke	Principal Investigator

References Module

Citations

PubMed Identifier	Type	Citation	Retractions
	Background	Freitag, C. M., Retz-Junginger, P., Retz, W., Seitz, C., Palmason, H., Meyer, J., ... & von Gontard, A. (2007). Evaluation der deutschen version des Autismus-Spektrum-Quotienten (AQ)-die Kurzversion AQ-k. Zeitschrift für klinische Psychologie und Psychotherapie, 36(4), 280-289.
	Background	Döring, N., & Bortz, J. (1993). Psychometrische Einsamkeitsforschung: Deutsche Neukonstruktion der UCLA Loneliness Scale. Zeitschrift für Klinische Psychologie, 22(3), 224-233.
	Background	Lang, G. & Bachinger, A. Validation of the German Warwick-Edinburgh Mental Well-Being Scale (WEMWBS) in a community-based sample of adults in Austria: a bi-factor modelling approach. J Public Health 25, 135-146 (2017).
	Background	Grimm, J. State-trait-anxiety inventory nach Spielberger. Deutsche Lang- und Kurzversion. Methodenforum der Universität Wien: MF-Working Paper (2009).
	Background	Schwarzer, R., Bäßler, J., Kwiatek, P., Schröder, K., & Zhang, J. X. (1997). The assessment of optimistic self-beliefs: comparison of the German, Spanish, and Chinese versions of the general self-efficacy scale. Applied Psychology, 46(1), 69-88.
	Background	Fliege, H., Rose, M., Arck, P., Levenstein, S. & Klapp, B. F. (2001). Validierung des "Perceived Stress Questionnaire" (PSQ) an einer deutschen Stichprobe. Diagnostica, 47, 142-152.

IPD Sharing Statement Module