All in - 03/02/2026
When we think about the benefits of exercise, most of us picture stronger muscles, a healthier heart, or a calmer mind. But over the past decade, scientists have discovered another powerful effect of moving your body—exercise changes your gut microbiome, the vast community of trillions of bacteria, fungi, and other microorganisms living in your digestive system.
And the health of that community is far more important than many of us realise.
Here’s a fun fact: your gut microbiome weighs around 1–2 kilograms—about the same as your brain. That’s a lot of life working away inside you.
These microbes don’t just help you break down food. They also:
Produce vitamins and essential compounds your body can’t make on its own
Regulate fat metabolism and blood sugar control
Support your immune system and influence inflammation throughout your body
Communicate with your nervous system, affecting mood, energy, and even brain function
When your microbiome is diverse and balanced, it supports resilience and wellbeing. But when it becomes less diverse—something seen in obesity, autoimmune conditions, and cardiometabolic disease—it can contribute to poor health. One important bacterium, Faecalibacterium prausnitzii, is known to produce an anti-inflammatory compound called butyrate. People with low levels of this “good bug” are more prone to inflammatory bowel disease, obesity, and depression.
This is where movement comes in. Exercise has been shown to:
Increase diversity of gut microbes, a key marker of health
Boost butyrate-producing bacteria, including Faecalibacterium prausnitzii
Lower harmful bacteria linked with bowel disease and chronic inflammation
Increase short-chain fatty acids (SCFAs), compounds that strengthen the gut barrier, fuel gut cells, and regulate the immune system
One fascinating study showed that after just six weeks of moderate exercise three times a week, sedentary adults increased the number of butyrate-producing bacteria in their gut. Even more interesting? When participants stopped exercising, their microbiome quickly returned to its original state. Just like muscles, your gut microbes thrive on consistency.
Other research has found that both moderate continuous exercise and high-intensity interval training can shift the microbiome toward a healthier balance, increasing bacteria that support metabolism and reducing those that trigger inflammation.
The gut is sometimes called the body’s “second brain” for good reason. A healthier microbiome has been linked with:
Reduced inflammation and stronger immune function
Lower risk of chronic conditions such as type 2 diabetes and heart disease
Better energy metabolism and healthier weight management
Improved mood and mental health through the gut–brain axis
Exercise doesn’t just keep your heart and muscles strong—it builds a more resilient internal ecosystem that protects you for years to come.
The good news is that you don’t have to be an elite athlete to see the benefits. Studies show that 30–60 minutes of moderate aerobic exercise, three times per week, can already make a difference to your microbiome. Pairing this with resistance training and a diet rich in plant fibre gives your gut the fuel and stimulus it needs to thrive.
And just like strength training, variety matters. Different forms of movement stimulate your body in different ways, and that variety can also support a more diverse and adaptable microbiome.
As scientists continue to uncover the fascinating connections between exercise and the trillions of organisms living within us, one thing is clear: moving your body is one of the most powerful ways to nurture your inner ecosystem—and in doing so, to support your long-term health.
All in - 03/02/2026
