Your Gut, Your Immune System, and Movement: Why They’re More Connected Than You Think
Written by Sarah Colston - Physiotherapist -
Have you ever noticed that your stomach seems to react to everything?
Stress.
Poor sleep.
A busy week.
Even changes in activity levels.
One day everything feels calm and settled. The next day your tummy feels bloated, uncomfortable, or unpredictable.
It can feel frustrating… but there’s a fascinating reason this happens.
Your gut isn’t just a digestive tube. It’s actually one of the largest immune organs in your body — and it’s constantly communicating with your immune system and inflammatory responses. When those systems fluctuate, your gut often feels it first.
Let’s unpack why.
Your Gut and Your Immune System Are Constantly Talking
Around 70% of the body’s immune system is linked to the gut. That means your digestive system isn’t just responsible for absorbing nutrients — it’s also helping regulate how your body responds to inflammation, infection, and stress.
Inside your gut live trillions of microbes (your gut microbiome). These bacteria interact with your immune system and influence how strongly your body reacts to potential threats.
When things are balanced, the gut lining stays strong, and the immune system responds appropriately.
But when inflammation increases — due to illness, stress, diet changes, or inactivity — the gut can become more sensitive.
This can lead to symptoms like:
bloating
cramping
unpredictable bowel movements
food sensitivities
general abdominal discomfort
Researchers are increasingly recognising that gut symptoms are often a reflection of immune activity and inflammation in the body.
The Role of Inflammation
Inflammation gets a bad reputation, but it’s actually an essential process.
It’s how the body repairs tissue, fights infection, and adapts to stress.
The challenge occurs when inflammation becomes chronic or poorly regulated.
When inflammatory molecules (like cytokines such as IL-6, CRP, and TNF-α) stay elevated, they can influence many systems in the body — including the gut.
This can affect:
gut motility (how quickly food moves)
gut sensitivity
the balance of gut bacteria
the integrity of the gut lining
That’s why periods of higher inflammation often coincide with digestive symptoms.
But here’s where things get interesting…
Your body has powerful ways to regulate inflammation naturally.
And one of the most effective is movement.
How Exercise Helps Regulate Gut Inflammation
Exercise isn’t just good for muscles and joints.
It actually acts like a powerful regulator of the immune system.
When we move, contracting muscles release signaling molecules called myokines. These molecules communicate with the immune system and help shift the body toward an anti-inflammatory state.
In practical terms, regular movement can:
reduce chronic inflammation
improve immune regulation
support healthy gut bacteria
strengthen the gut barrier
Moderate exercise has been shown to increase beneficial anti-inflammatory signals while lowering pro-inflammatory markers in the body.
Over time, this can help stabilise the immune system and reduce the fluctuations that often trigger gut symptoms.
Exercise Also Strengthens the Gut Barrier
Your gut lining acts like a protective filter.
It allows nutrients to pass into the bloodstream while keeping harmful substances out.
Moderate exercise has been shown to improve the proteins that maintain this barrier, strengthening the gut lining and supporting microbial diversity.
When the gut barrier is stronger, the immune system doesn’t need to react as aggressively — which means less inflammation and often fewer digestive symptoms.
Finding the Right Balance
Interestingly, more exercise isn’t always better.
Very intense or prolonged exercise can temporarily increase gut permeability and inflammatory responses, particularly if recovery, hydration, or nutrition are poor.
For most people, the sweet spot is consistent, moderate movement.
Think:
walking
swimming or hydrotherapy
cycling
gentle strength training
mobility work
These types of exercise help train the immune system to respond appropriately without overwhelming it.
What This Means for Your Gut
If your digestive system feels unpredictable, it may not just be about what you’re eating.
It may also be about how your immune system and inflammation are behaving.
Movement helps regulate that whole system.
Not by forcing the gut to behave…
…but by creating the internal environment that allows it to settle.
The Takeaway
Your gut, immune system, and inflammation are deeply connected.
When inflammation rises, the gut often feels it first. When the immune system is balanced, digestion usually feels calmer too.
Regular movement is one of the most powerful ways to support that balance.
Small, consistent exercise helps your body regulate inflammation, strengthen the gut barrier, and support the microbiome that keeps everything running smoothly.
And sometimes, the best thing you can do for your tummy…
is simply move a little more
References:
J. Álvarez‐Herms and J. Álvarez‐Herms, “Microbiome and physical activity,” Advances in Genetics, pp. 409–450, Jan. 2024, doi: 10.1016/bs.adgen.2024.01.002
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