Can social support change the impact of stress on gastric functioning?

This study is a two-arm randomised controlled trial with a single intervention group. Participants will attend a single 120-minute laboratory session during which they will undergo a stressful task, as explained below. Participants will not be told that there are two different groups. They will be told that the social support components of the study involve the use of questionnaires and simulated behaviors enacted by the researcher running the session. All participants in both groups will arrive at the laboratory and physiological measures of stress and gastric activity will be set-up. These include a non-invasive Body Surface Gastric Mapping device designed by Alimetry Ltd, and non-invasive sensors that detect changes in heart rate, heart rate variability, blood pressure, electrodermal activity, and hand temperature. The Gastric Alimetry device will be used to measure gastric activity continuously throughout the study, for a period of approximately 110 minutes. The device will be applied to participants using a standardised procedure in which the skin is prepped with NuPrep gel before the adhesive electrode array is placed. Participants will fill in questionnaires about their experiences of social support in adulthood and childhood and then consume a standardised meal. The standardised meal includes a nutritional shake and protein bar, collectively consisting of approximately 482 kCal. Participants will then complete the 10-minute Maastricht Acute Stress Test to induce a stress response, and then remaining seated in a recliner during a post-stressor observation period. Participants who were randomly assigned to the intervention group will receive a supportive behaviour intervention administered by the experimenter. Throughout the procedure, the experimenter will engage in evidence-based supportive behaviours. These behaviours will be standardised across participants in accordance with a script. The intervention consists of verbal behavioural manipulations of experimenter warmth, competence, and provision of information to the participant. These manipulations are designed to produce high levels of emotional and informational support. The extent of participant engagement with the intervention will be directly observed. The experimenter is a postgraduate student in health psychology who has received training in the provision of supportive behaviours. Study-specific training will be administered by the project supervisor and an additional advisor 3-weeks prior to the first participant enrolment, and will occur face-to-face over 3 hours.