Exercise is good for your guts – especially the microbiome!

The health benefits of regular exercise are well established, but the latest research has identified new and unexpected advantages, and it’s all about the gut.

Researchers from Australian Catholic University and Hudson Institute of Medical Research have established that many gut disorders can be added to the list of things that physical activity is good for.

Lead author, Professor John Hawley, said exercise imparts many of its whole-body health benefits by releasing small proteins from the exercising muscles, which communicate with other organs and tissues throughout the body.

“The exciting part is that we now realise that skeletal muscles don’t just “talk” to fat and bone tissue, but they also “communicate” with the gut microbiome,” Prof Hawley said.

“I can’t think of anything that exercise is not good for, but the link between exercise and the gut microbiome is new and the more we find out about it, the more exciting it is.”

Exercise, the microbiome and the gut-muscle axis

He believes research into the muscle-gut axis is an area which will really explode in the next decade, much as people are now exploring the link between exercise, the gut microbiome and brain health.

The key to these connections is the release of myokines from contracting skeletal muscles, which create interorgan communication which, in turn, confers protection against numerous disease states. A seminal discovery in this area over two decades ago was the work of a Melbourne researcher, Professor Mark Febbraio.

Working with paediatric gastroenterologist, Associate Professor Edward Giles and microbiome specialist, Associate Professor Sam Forster, Prof Hawley now aims to understand why exercise is so powerful in modifying the gut microbiome and thereafter, possibly some of the diseases and conditions that are linked to the gut.

“We know the benefits of exercise are widespread, but we’ve recently discovered, for example, that athletes have greater diversity in their gut microbiome than the general population.” he said.

“The exact amount and type of exercise required to induce favourable changes in the microbiome and enhance host immunity is currently unknown, but it’s all relative – for people who are just beginning to exercise, the dose is probably quite small to induce beneficial alterations.” 

Keep up the exercise

But the news is not all good!

“As soon as you stop training,” Prof Hawley cautioned, “…you start to lose the gut microbiome diversity, so the point is it’s very transient, and the benefits are only maintained with regular exercise.”

“Of course, you have to take into consideration a person’s diet in all of this and, as the saying goes, you can’t outrun a bad diet.”

A/Prof Giles believes this study offers hope for the many people who suffer gut diseases, such as Inflammatory Bowel Disease (IBD).

“We know there is huge variation in the human gut microbiome, but it’s equally true that reduced microbial diversity is a factor in several diseases of the gastrointestinal (GI) tract, systemic immune diseases, and cancers,” he said.

“Physical activity boosts host immunity, facilitates a more diverse gut microbiome and functional metabolome, and plays a positive role in energy homeostasis and metabolic regulation.”

But he cautioned that there are limits to these benefits: “Heat appears to be a limiting factor – beyond a certain temperature the body sends less blood to the muscles and any time there’s this “fight for bloodflow” the gut tends to lose out, so exercising in the heat is bad for GI disorders.”

But the final word goes to Prof Hawley: “The bottom line is if you’re not exercising you should be. Will it have a beneficial effect on the gut microbiome? Absolutely. Will it have a beneficial effect on almost everything else? Absolutely.“