Is extreme exercise bad for you?

We can all get on board with the idea that exercise is good for you and that Netflix marathons with a regular beer and pizza diet isn't, but is there a point where exercise can actually cause you harm? Research conducted by Monash University has discovered that extreme exercise can cause intestinal bacteria to leak into the bloodstream, leading to blood poisoning and so we ask how much exercise is good exercise? The research, published in the International Journal for Sports Medicine1 compared the blood samples of athletes before and after a 24 hour endurance event with a control group and found that exercise over a prolonged period causes the wall of the gut to change, allowing bacteria to enter the bloodstream. This triggers an inflammatory response in the body similar to a serious infection and can be potentially fatal. However, the study also found that individuals who are fit, healthy and steadily build up to endurance events develop immunity to this with no side effects. Those who compete with little training or in extreme temperatures can put their body under a massive amount of strain however and may be at risk to sepsis induced systematic inflammatory response syndrome which can be fatal. The lead researcher Dr Ricardo Costa from the Department of Nutrition and Dietetics stated that; "Nearly all of the participants in our study had blood markers identical to patients admitted to hospital with sepsis"2 and the research reinforces the current guidelines for endurance athletes of getting a health check, then steadily progressing an endurance tailored training program. Those that were fitter with training over a longer period of time leading up to an ultra-endurance event were found to have higher levels of `Interleukin 10`, an anti-inflammatory agent which helps to lessen the effect of immune response. The number of people entering into ultra-endurance events is on the increase with people wanting to see how far they can push themselves. As the name suggests however, these are endurance events and shouldn't be entered into lightly or, as the research suggests, you could be putting your health at risk in the long run. The vast majority of people won't enter into an ultra-endurance event without at least a year of dedicated training towards it, and so this research, although interesting in terms of seeing how ultra-exercise affects us physiologically is not exactly a massive panic for the fitness community and the fact remains that if you want to enter endurance events, train or you'll hurt yourself! Exercise may eventually be bad for you, bit it's about listening to your body, and some exercise is always better than no exercise at all, especially for beginners who can slowly build their fitness levels up to improve general health and perhaps one day compete.
1- https://www.thieme-connect.de/DOI/DOI?10.1055/s-0034-1398535
2 - http://www.sciencedaily.com/releases/2015/06/150616093646.htm