The gut barrier is critical for human health, balancing nutrient absorption while protecting against harmful luminal antigens. Both physiological stressors (e.g., intense exercise, heat, hypoxia) and psychological stressors (e.g., anxiety, sleep disruption) can disrupt barrier integrity, resulting in gut discomfort, inflammation, and systemic responses. Importantly, barrier dysfunction can influence mood and cognition via the gut-brain axis and physical performance and recovery via the gut-muscle axis.

Stress-induced barrier dysfunction arises through multiple mechanisms, including disruption of tight junctions, hypoxia- and ischemia-related injury, and oxidative and inflammatory stress, with the gut microbiota acting as a modulator of these processes. Nutrition, including dietary components, supplements, and probiotics, provides opportunities to protect and restore barrier integrity and reduce discomfort in stress-exposed populations. Exercise also plays a dual role: while intense activity can act as a barrier stressor, regular, moderate exercise can strengthen and maintain gut barrier function, highlighting its complex contribution to resilience.

This Research Topic places gut barrier function at the centre of stress, nutrition, and exercise research. We seek to bring together studies exploring how stressors compromise barrier integrity, how dietary and microbial interventions can improve barrier function, and how exercise acts both as a challenge and a protective factor for the gut. We are interested in how barrier dysfunction contributes to local gastrointestinal discomfort and exerts systemic effects via the gut-brain axis (impacting mood, cognition, and mental wellbeing) and the gut-muscle axis (influencing physical performance, recovery, and fatigue).

The goal is to synthesise knowledge of the mechanistic underpinnings (e.g., tight junction regulation, immune responses, hypoxia-induced injury) alongside the modulatory role of the gut microbiota, and link these to functional outcomes including gut discomfort, impaired wellbeing, and reduced performance. By integrating in vitro studies with human intervention and performance studies, this collection will provide a comprehensive view of how to preserve gut barrier integrity and improve health outcomes in stress-exposed groups such as athletes, military personnel, and ageing individuals.

We welcome contributions that address:

- Physiological and psychological stressors that disrupt gut barrier integrity (e.g., intense exercise, heat, hypoxia, inflammageing, sleep deprivation, chronic stress, anxiety).

- Nutritional and microbial strategies (nutrients, supplements, probiotics, functional foods) to prevent or mitigate dysfunction.

- Exercise as both a barrier stressor and a protective factor through regular, moderate activity.

- Mechanistic drivers of barrier dysfunction, including tight junction regulation, immune responses, and hypoxia-related damage, as well as the modulatory role of the gut microbiota.

- Downstream consequences of barrier dysfunction in the gut, particularly gut discomfort and inflammation.

- Systemic effects via the gut-brain axis (mood, cognition) and the gut-muscle axis (physical performance, recovery).

- Studies in key populations: athletes, military personnel, and ageing individuals.

- Methodological advances in in vitro and human models for gut barrier research.

We invite original research, reviews, mini-reviews, perspectives, and methodological papers, spanning molecular to translational research.

Are you interested in contributing a manuscript to this Research Topic?

Gut Barrier Function in Stress and Health: Nutrition, Exercise, the Microbiome, and Gut-Brain-Muscle Interactions