How Boot Camp Training Changes Your Gut Reactions

Boot camp training programs claim to help you get fit, and the fact that you push your body to its limits of endurance indicate that the boot camp training can get results. But at what cost?

Military-style boot camp training programs are all the rage these days. You can’t walk into a gym or fitness center without seeing a half-dozen flyers for all sorts of boot camps, each with their own unique approach to fitness through prolonged periods of physical exercise.

They offer a week or weekend of pushing your body to its limits to get the results you want. Sounds pretty good, right? But what you may not know is that military-style/boot camp training programs can actually be harmful to your body.

A study published in the American Journal of Physiology — Gastrointestinal and Liver Physiology detailed how military-style training programs could have seriously negative effects on the gut microbiota (the beneficial bacteria living in your intestines).

The researchers gathered 73 Norwegian Army soldiers and subjected them to four days of military-style training: skiing 31 miles while carrying a 99-pound pack. Blood, urine, and stool samples were taken before and after the training in order to determine the effects of the prolonged physical exercise.

The soldiers were given sucralose, which the body doesn’t digest but excretes via urine. The sucralose excretion levels rose sharply by the end of the test, indicating an increase in intestinal permeability. Simply put, intestinal permeability indicates that more bad materials are passing out of the intestines. This leads to a higher risk of diarrhea, illness, and inflammation.

Not only did intestinal permeability increase, but the researchers also found significant changes in the gut bacteria after the training. The concentrations of fat-digesting and protein-digesting bacteria were affected negatively by the intense, prolonged physical exercise. This indicates that digestion and absorption of nutrients are very likely compromised by the military-style training.

Boot camp training programs claim to help you get fit, and the fact that you push your body to its limits of endurance and strength indicate that the military-style training can get results. But at what cost? According to this study, the hardcore training programs may strain your digestive system, interrupt the absorption of vital nutrients, and potentially lead to inflammation and illness.

Does that mean you should avoid boot camp/military-style training programs? Not necessarily, but it’s important you undertake them with your eyes open. You need to understand the cons as well as the pros, and what the hardcore training can do to your body. That way, you won’t be surprised if you notice digestive changes, inflammation, or illness after the training is completed. More important, you can take steps to prevent health problems.


1. J. Philip Karl, Lee M Margolis, Elisabeth H Madslien, Nancy E Murphy, John W. Castellani, Yngvar Gundersen, Allison V Hoke, Michael W Levangie, Raina Kumar, Nabarun Chakraborty, Aarti Gautam, Rasha Hammamieh, Svein Martini, Scott J. Montain, Stefan M. Pasiakos. “Changes in intestinal microbiota composition and metabolism coincide with increased intestinal permeability in young adults under prolonged physiological stress.” American Journal of Physiology – Gastrointestinal and Liver Physiology, 2017; ajpgi.00066.2017. 

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