Summary: Researchers analyzed the complex bidirectionality of the gut-brain axis under rapid time zone changes. When sleep schedules, light exposure, and meal timings shift abruptly, communication across the gut-brain-immune axis breaks down.
This temporal misalignment compromises intestinal barrier integrity, reduces the synthesis of beneficial short-chain fatty acids (SCFAs), and temporarily shifts microbial balance toward less beneficial strains. To combat these symptoms, the authors advocate for chrononutrition, pre-travel light management, and targeted synbiotic protocols to entrain peripheral tissue clocks alongside the brain.
Key Facts
- Gut-Brain Rhythm Desynchronization: Trillions of gut microbes operate on daily circadian oscillations synchronized with host feeding patterns. Rapid time zone shifts cause the host’s brain clock and peripheral intestinal clock to run on conflicting schedules.
- Intestinal Barrier & SCFA Compromise: Trans-meridian travel decreases the microbial production of short-chain fatty acids (acetate, propionate, butyrate) while compromising tight junctions in the intestinal barrier, increasing systemic inflammation.
- Altered Gastrointestinal Dynamics: Abrupt changes in meal times alter bile acid production, digestive enzyme secretion, and gut motility, promoting transit delays, constipation, and dysbiosis.
- Chrononutrition Strategy: Aligning meal times with the destination’s daytime hours before and during flight entrains peripheral metabolic clocks, preventing feeding during biological nighttime hours.
- Broader Occupational Impact: Beyond long-haul travelers and athletes, gut jet lag mechanisms chronically affect shift workers, airline personnel, and individuals living under severe “social jet lag”.
Source: Wroclaw Medical University
A dream holiday, an exotic destination, a long-haul flight, and finally some well-deserved rest. The problem is that many travelers arrive at their destination only to spend the first days of their vacation struggling with fatigue, sleep disturbances, low energy levels, and digestive issues.
Researchers from Wroclaw Medical University point out that these symptoms may be caused by more than just classic jet lag. A growing body of evidence suggests that time zone changes also affect the trillions of bacteria living in our intestines.
This phenomenon, known as “gut jet lag,” describes a disruption in synchronization between the human biological clock and the rhythms of the gut microbiota. Although the concept is relatively new, researchers agree that our intestines may need just as much time as our brains to adapt to a new time zone.
Gut jet lag is a relatively new concept describing a state of desynchronization between the human biological cycle and the rhythms of gut bacteria. A short trip within Europe is unlikely to cause such major disruptions, but the problem becomes significant during long-haul flights that involve crossing multiple time zones ,- explains co-author Karol Biliński. – Under these conditions, fatigue and dietary changes can compromise intestinal barrier integrity and reduce the production of beneficial short-chain fatty acids.
Why do we feel worse after a long-haul flight?
Intercontinental travel means much more for the body than simply changing the time on a watch. Within a matter of hours, sleep schedules, meal times, light exposure, and stress levels all change dramatically. For the body, it is a major upheaval.
Our digestive system is extremely sensitive to these changes because the entire gut-brain axis operates according to a tightly regulated circadian rhythm. When biological signals become misaligned, communication between the intestines, immune system, and brain is temporarily disrupted ,- explains co-author Kacper Wiśniewski. – This temporary dysregulation is responsible for digestive complaints, poorer sleep quality, and reduced energy levels in many people during the first days after arrival.
This helps explain why the first days of a vacation are often the least comfortable. While the body is trying to adapt to new environmental conditions, gut bacteria may still be operating according to the schedule of the departure location.
When your gut cannot keep up with your journey
Many travelers experience constipation, bloating, a feeling of heaviness, or changes in appetite after arrival. Although local cuisine is often blamed, the underlying cause may be much more complex.
A sudden shift in meal timing directly affects the secretion of digestive enzymes, bile production, and gastrointestinal motility, says co-author Laura Rafner. – As a result, the balance of the gut microbiome may temporarily shift in favor of less beneficial bacterial strains. This can slow intestinal transit and lead to constipation and digestive discomfort.
The researcher notes that disruptions in the microbiota may also impair sleep quality, thereby worsening fatigue. This creates a vicious cycle that makes recovery from travel more difficult.
How not to waste the first days of your holiday
The good news is that the effects of jet lag can be reduced. Proper preparation before departure is crucial.
The key is to gradually adjust your biological clock to the destination time zone. This process should ideally begin several days before departure through appropriate management of light exposure and sleep schedules,- emphasizes co-author Paweł Witko.
Researchers also highlight the importance of chrononutrition, which means eating in alignment with the body’s biological rhythms. In practice, this means adopting the destination’s meal schedule before arrival.
While on the plane and after landing, meals should be consumed only during the daytime hours of the destination time zone, while eating during your biological night should be strictly avoided,- explains Paweł Witko. – It is also important to stay well hydrated and consider starting individualized probiotic and prebiotic supplementation before travel.
Melatonin may also be helpful, although the authors stress that its effectiveness depends heavily on the timing of administration.
The problem is not limited to travelers
Although the publication focuses on athletes traveling to competitions, its conclusions have much broader implications.
Studies involving shift workers and airline personnel suggest that ‘living against nature’—through shift work and irregular eating patterns—can significantly affect our microbiome, – says Dagmara Beata Gaweł-Dąbrowska, PhD, Professor at Wroclaw Medical University and head of the research team. – Maintaining good sleep hygiene, regular meal schedules, and appropriate exposure to daylight is not only important for athletes but forms the foundation of health for all of us.
In practice, similar mechanisms may affect millions of people who live in a constant state of time pressure, work shifts, or regularly disrupt their circadian rhythms.
Start your vacation by taking care of your biological clock
According to the researchers, preparing for a trip should involve more than booking flights, reserving hotels, and packing luggage.
To fully enjoy a vacation, we need to take care not only of our travel plans but also of our health,- summarizes Dr. Dagmara Beata Gaweł-Dąbrowska. – Long-distance travel is a major stressor for the body and can disrupt our internal clock. A conscious approach to our physiology may help us avoid spending the first days of a holiday battling fatigue and digestive problems, allowing us to enjoy our time away from the very beginning.
Vacations are meant to provide new experiences and renewed energy. However, growing scientific evidence suggests that to make the most of our travels, we should also remember the unseen passengers who accompany us wherever we go—the trillions of bacteria living in our intestines.
Key Questions Answered:
A: Gut jet lag is the state of desynchronization between the human master circadian clock in the brain and the peripheral biological clocks of the gut microbiota. It occurs when travel shifts environmental cues faster than intestinal microbes can adapt, leading to digestive distress and metabolic fatigue.
A: While light exposure primarily resets the master clock in the brain (the suprachiasmatic nucleus), meal timing serves as the primary synchronizer for peripheral clocks in organs like the liver and intestines. Eating during your biological night confuses peripheral tissues and disrupts microbial rhythms.
A: Travelers should shift light exposure and sleep schedules toward the destination time zone several days in advance, adopt destination meal times immediately (avoiding meals during biological night), remain hydrated, and consider pre-departure prebiotic or probiotic support.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this microbiome and circadian rhythm research news
Author: Dorota Sikora
Source: Wroclaw Medical University
Contact: Dorota Sikora – Wroclaw Medical University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Travel-Induced Circadian and Microbiota Disturbances: Implications for Athlete Health and Performance: A Narrative Review” by Karol Biliński, Kacper Wiśniewski, Laura Rafner, Paweł Witko, Dagmara Gaweł-Dąbrowska. Nutrients
DOI:10.3390/nu18101523
Abstract
Travel-Induced Circadian and Microbiota Disturbances: Implications for Athlete Health and Performance: A Narrative Review
High-performance athletes are increasingly exposed to frequent trans-meridian travel, leading to profound circadian desynchronization and gastrointestinal distress. This review examines the complex interplay between the host’s central circadian system and the gut microbiota (GM), both of which exhibit synchronised daily oscillations essential for homeostasis.
Rapid time-zone transitions, such as those anticipated for the 2026 FIFA World Cup, induce a state of “gut jet lag,” characterised by the loss of rhythmic microbial functions and impaired intestinal barrier integrity. Circadian misalignment is associated with increased systemic inflammation and disrupted metabolic regulation, which may contribute to impairments in cognitive performance, sleep quality, and muscle recovery.
Critically, travel-induced dysbiosis may reduce the production of microbial metabolites, specifically short-chain fatty acids (SCFAs) like acetate, propionate, and butyrate. These SCFAs serve as energy substrates that may enhance glucose uptake, lipid oxidation, and glycogen storage in skeletal muscle. Evidence suggests that travel-related stressors—including dehydration, psychological stress, and shifts toward highly processed diets—further exacerbate the loss of beneficial taxa.
To mitigate these effects, this article proposes evidence-informed strategies: timed light exposure to reset the master clock, chronobiotic meal timing to entrain peripheral tissues, and targeted symbiotic supplementation to restore SCFA-producing populations. Integrating these personalised, evidence-informed protocols may support the optimisation of physiological resilience and performance.
