Are gut bacteria the secret to qualifying for Kona?

Researchers are looking for competitors at the 2022 Ironman World Championship to take part in a study that will investigate the role the gut microbiome plays in endurance performance

KAILUA KONA, HAWAII - OCTOBER 10: In this handout photograph provided by Ironman, Athletes compete in the 112-mile (180.25 km) bicycle rides during the IRONMAN World Championship presented by GoPro on October 10th 2015, Kailua Kona, Hawaii. (Photo by Nils Nilsen/IRONMAN via Getty Images) IRONMAN Triathlon consists of a 2.4-mile (3.86 km) swim, a 112-mile (180.25 km) bicycle ride and a marathon 26.2-mile (42.2 km) run. IRONMAN is considered one of the most difficult endurance events in the world.

This October, researchers from all over the world will be teaming up for a first-of-a-kind study on probiotics and the gut microbiome of triathletes at the Ironman World Championship in Kona, Hawaii.


The highly competitive field combined with the gruelling conditions on the Pacific island of Hawaii will serve as the perfect venue for this project, which is being led by scientists from Liverpool John Moores, Georgia Southern University, and The University of Illinois at Urbana-Champaign.

How hot can it get at the Ironman World Championship?

Widely regarded as one of the toughest triathlons on the planet, the Ironman Worlds sees the world’s top long-distance triathletes competing in temperatures that can exceed 40°C (104°F) on certain parts of the course, and in sometimes 90% humidity.
These unique conditions will enable the researchers to examine the relationship between exercise and the gut microbiome at the peak of physiological extremes.

Are gut bacteria the secret to qualifying for the Ironman World Championship?

By examining how the gut microbiota respond to such a stimulus, how this response is influenced by probiotic supplementation, and the relationship between our gut microbiota and race performance and GI distress, this study will answer a number of important questions that will be essential in optimising human performance, and possibly your future spot in Kona.

Our digestive tract contains ~40 trillion bacteria (also known as our gut microbiota) that play an important role in many aspects of our health and wellbeing.

Relevant to athletes, our gut microbiota can influence race performance by regulating energy production and utilisation as well as modifying our risk for gastrointestinal distress (e.g., bloating or nausea).

How to take part in the study

If you are competing at this year’s Ironman World Championship in Kona, Hawaii, and would like to get involved, please complete this brief survey:

If you have any questions, please contact study coordinators Dr. John Molphy ( or Dr. Greg Grosicki (

Top image: Nils Nilsen/Ironman via Getty Images