What travel asks of an athlete before competition even begins.
As anyone who travels knows, our digestive systems do not recognize TSA PreCheck. Change time zones, food, sleep schedule, and bathroom routine, and the body can become surprisingly opinionated about the whole experience.
Annoying when you're traveling for pleasure, but potentially much more consequential when you're expected to perform at an elite physical level a few hours after landing.
In the first article in this series, I wrote about how sophisticated professional sports has become at measuring recovery. Teams can monitor sleep, heart rate variability, training load, hydration, blood biomarkers, and a remarkable number of other physiological signals.
But travel? That adds another variable. An athlete doesn't necessarily arrive at an away game in the same biological condition in which they left home. I'm not an athlete and even I could figure that out. I just hadn't thought beyond my own body before. Still, the more I read, the more interesting it became.
Travel Is More Than Transportation
I always thought about travel in sports pretty much the way any casual fan does. Home game. Away game. Get on the plane. Get off the plane. Play. I clearly underestimated what happens in between.
Sports researchers distinguish between travel fatigue, the normal fatigue associated with a trip, and jet lag, which occurs when crossing enough time zones to disrupt the body's internal clock. Even without significant jet lag, travel can change sleep, hydration, meal timing, food choices, physical activity, and routine. Long distance travel can also add circadian disruption to the list.
A comprehensive 2026 review of athlete travel describes exactly how complicated this can become. The authors examined sleep, circadian rhythm, nutrition, hydration, environmental changes, and gastrointestinal issues as interconnected considerations rather than isolated problems. In other words, travel isn't simply transportation for an athlete. It's a biological event.
Excuse me. What did that say?
The Body Has More Than One Clock
Most of us understand the basic idea of a body clock. If you fly across several time zones, your brain may know you've landed in a new city while your body remains quite convinced it's somewhere else.
Long travel can throw you off even when you never cross a time zone. That's travel fatigue. Cross enough time zones, and now the body's internal clock has to catch up too. That's where jet lag enters the picture. Either way, the disruption goes well beyond sleep.
Our circadian system helps organize hormone secretion, metabolism, immune activity, digestion, and other physiological processes across roughly 24 hours. And the gut, my friend and yours, appears to participate in that rhythm too.
Gut microbial communities and their functions can fluctuate throughout the day, influenced in part by eating and fasting patterns. Meal timing is one of the signals that helps coordinate these rhythms. A 2025 review of chrononutrition and gut health describes growing evidence connecting meal timing, circadian disruption, microbial balance, gut barrier function, and metabolic health.
Now put an athlete on a plane. Breakfast may suddenly be offered when the body thinks it should be sleeping. Dinner hour moves. The time for sleep changes even more. Light exposure may change. The kinds of foods the athlete eats may change. Practice times may change. Then competition arrives according to the clock on the wall, whether the athlete's internal biology has caught up or not.
The Microbiome Travels Too
So what does all of that mean for professional athletes? This is the cool part, at least for me.
A 2026 review published in Nutrients looked specifically at travel induced circadian disruption and the gut microbiota in athletes. The authors describe travel as a combination of stressors that can include circadian misalignment, dehydration, dietary changes, psychological stress, and altered sleep. Those factors may also affect the composition and function of the gut microbiome.
Another 2026 review on athlete travel notes that international travel has been associated with changes in microbial diversity and composition, even in people who do not become obviously ill. At the same time, the authors are pretty cautious. Research specifically demonstrating that probiotic supplementation protects traveling athletes is still limited, and responses can depend heavily on the strain, dose, diet, and individual athlete. I appreciate that distinction.
I would love nothing more than telling you that a product like Original Biome saves the day. But this isn't a story about discovering a magic probiotic that eliminates jet lag. And, unfortunately for us, biology is rarely that cooperative. Instead, it's a story about acknowledging the idea that another biological system that may be affected by travel, and it opens a lot of discussion doors.
What Happens When the Gut Isn't Happy?
So how do we go from biology to practical performance?
Well, an athlete has to eat enough to perform and digest what they eat. They have to absorb nutrients and fluids. They need predictable gastrointestinal function. And they have to do all of that while training, competing, traveling, sleeping in unfamiliar places, eating on changing schedules, and managing stress. GI trouble isn't simply uncomfortable in that environment.It can interfere with fueling, hydration, sleep, training, and competition.
Now, I'm not trying to say every athlete has gastrointestinal problems when traveling. And I'm also not saying gut health determines whether someone performs well. I want to, but I'm not.
I'm saying the gut is participating in the travel, with all of its little microbial friends. And it's going to send messages when something is off.
Teams Already Manage Travel. Should Gut Stability Be Part of the Plan?
Here's another piece of this whole professional athlete world I have somehow smashed into. Professional teams aren't ignoring travel physiology. Far from it. Did you know that? Because I surely did not.
Performance departments already think carefully about sleep schedules, light exposure, hydration, meal timing, training, recovery, and strategies for adjusting to new time zones. Some organizations use wearable data to see how individual athletes are responding, which makes sense.
But if circadian rhythm, meal timing, stress, hydration, sleep, and the microbiome all interact, and we know that, then maybe it is time to consider gut health and gut stability as part of the travel plan. Not as a replacement for sleep strategy. Not instead of proper nutrition. And certainly not as the explanation for every poor recovery score after a road trip. But it makes sense to add it as another variable.
This is where my obsession with fermentation enters the picture again. If you know me, my company, or have read any of my articles, you know that I have become a tremendous believer in fermentation as a way to bring together beneficial microbes, the substrates they use, and the compounds they create.
Prebiotics provide substrates that beneficial microorganisms can use. Probiotics introduce specific microorganisms. Fermentation also produces postbiotics and other microbial metabolites. Research is exploring how these different components may support gut barrier function, immune activity, microbial metabolism, and gastrointestinal health. Could supporting that environment make an athlete's gut more resilient to the disruptions that come with travel?
I don't know that answer. Again, I want to say yes, but the existing evidence isn't strong enough to say that. At least not yet. But this is precisely the sort of question I think becomes interesting when sophisticated performance measurement meets microbiome science. Well, at least for gut enthusiasts like me.
Maybe the Away Game Begins at Departure
The more I've read about this, the less sense it makes to think of an away game as beginning at tipoff, kickoff, puck drop, or first pitch. The biological demands may begin when the athlete leaves home. The flight, altered sleep, different meal schedule, the hydration changes, unfamiliar environment, the circadian adjustment, and, in a real sense, changes within the gut.
Professional sports has invested enormously in understanding what happens to athletes during competition and recovery. Travel may be one of those places where looking a little further upstream could be useful.
So here's the question I'm left with: If teams are already measuring how athletes respond to travel, should they also be asking what can be done to make the gut more resilient before the trip begins?
I don't know the answer. But once again, I think it's worth measuring. And I'm here for it.
References
Bajaj P, Sharma M. Chrononutrition and Gut Health: Exploring the Relationship Between Meal Timing and the Gut Microbiome. Current Nutrition Reports. 2025;14(1):79. doi:10.1007/s13668-025-00670-z.
Biliński K, Wiśniewski K, Rafner L, Witko P, Gaweł Dąbrowska D. Travel Induced Circadian and Microbiota Disturbances: Implications for Athlete Health and Performance: A Narrative Review. Nutrients. 2026;18(10):1523. doi:10.3390/nu18101523.
Hatamiya N, Holmes KE, Grosicki GJ, Swisher J, Duffaut C, Vail J, Logan Sprenger H, Donohoe B, Fielding F, Chapman CJ, Leota J, Facer Childs ER, Goldman JT. Optimizing Athlete Travel for Performance: A Scientific Blueprint for Athletes, Coaches, and Sports Medicine Staff. Sports Medicine. 2026;56:1381–1403. doi:10.1007/s40279-026-02455-y.
