Australian researchers have discovered that extreme exercise can cause intestinal bacteria to leak into the bloodstream, leading to blood poisoning.
Experts at Melbourne-based Monash University monitored people participating in a range of extreme endurance events, including 24-hour ultra-marathons and multi-stage ultra-marathons, run on consecutive days.
Blood samples taken before and after the events, compared with a control group, proved that exercise over a prolonged period of time causes the gut wall to change, allowing the naturally present bacteria, known as endotoxins, in the gut to leak into the bloodstream. This triggers a systemic inflammatory response from the
body’s immune cells, similar to a serious infection episode.
People taking part in extreme endurance events especially in the heat and with little training, put their bodies under enormous strain over the body’s protective capacity. With elevated levels of endotoxins in the blood, the immune system’s response can be far greater than the body’s protective counter-action. In extreme cases, it leads to sepsis induced systemic inflammatory response syndrome, which can be fatal if it is not diagnosed and treated promptly.
The study is led by Ricardo Costa from Department of Nutrition and Dietetics. Costa says, “anything over four hours of exercise and repetitive days of endurance exercise is considered extreme”.
Significantly, the study found that individuals who are fit, healthy and follow a steady training programme to build up to extreme endurance events, develop immune mechanisms to counteract this, without any side effects.