Intense workouts could add more than muscle to the list of physical benefits brought about by getting your sweat on. A new study shows that hard training can also positively affect the balance of your gut bacteria, leading to better digestive systems, and greater potential as far as making a PR. The latest science certainly adds new meaning to the term “gut check!”

Regular exercise is already encouraged for lean mass gains and mental health benefits, but these new findings, resulting from a study by Edith Cowan University in Australia suggest that the intensity of our training could promise even more, influencing the configuration of our gut microbiome. “Based on previous research, it appears that athletes have a different gut microbiota when compared with the general population,” explains Ph.D. candidate Bronwen Charlesson, who served as lead on the paper. “This includes greater total short chain fatty acid concentrations, alpha diversity, and an increased abundance of some bacteria and a lower abundance of others.”

Scientists at ECU wanted to find out the specific effects of exercise, so they designed separate training volume loads, and checked them against other gut health factors, such as diet, to see the if training related scenarios like oxygen uptake could influence the results.

How was the Study Carried Out?

Twenty-three highly trained, national level rowing athletes (11 male, 12 female) were studied during two, 3-day periods separated by one month. The first period included around 5 hours of rowing, cycling, and cross training over 3-days, while the high-intensity load asked for the same training, but for more than seven hours over three days, resulting in greater intensity as recorded by heart monitors.

What the Study Found

The higher training load was linked with a shift in multiple gut health markers:

  • Greater Short-Chain Fatty Acids For colon health, better metabolism and less inflammation.
  • Better Bacterial Composition Improving digestion and the breaking down of nutrients

“Another observation made during the research was the significant slowing of gut transit times in athletes during low training loads,” says Charlesson. While both groups ate the same amount of carbohydrates and fiber, they tended to choose less healthy foods during the low intensity training phase, perhaps further influencing the results. “This decline was related to increases in processed fast foods, decreases in fresh fruit and vegetables and a moderate increase in alcohol intake,” she explains. “These changes did impact the composition of the gut microbiome.”

Can Intense Workouts Improve Gut Health?

In terms of the benefits of gut health as relates to hitting our PRs, scientists have a working theory that the gut may develop a superior ability to process lactate and balance pH levels. Both benefits are known to improve an athlete’s performance and recovery. While the study did not prescribe a sweet spot for the number of hours that you should work out, or how many hours per week you should hit in total, gut health gains could well be made by upping the intensity of your own sessions and avoiding processed foods.