Extreme Exercise May Cause Blood Poisoning

Potential Dangers of Extreme Exercise

Extreme endurance races such as ultra marathons and triathalons, as well as intense workouts such as CrossFit and P90X are attracting more and more participants, but a recent study warns that those who don’t prepare well for these extreme events risk blood poisoning.

Dr. Ricardo Costa of the Department of Nutrition and Dietetics at Monash University in Australia conducted a study published in the International Journal of Sports Medicine that tested the blood of 24-hour marathon participants before and during the race, and compared them to a control group.

The researchers found that extreme exercise causes disruptions in the walls of your intestines. As your push past your body’s limits, these gut disruptions can allow bacteria from your intestines to leak into your blood, potentially causing a dangerous and potentially fatal inflammatory response.

The tests of runners’ blood during and after the extreme exercise events showed markers that indicate sepsis – or the body’s inflammatory response to an infection. (If this condition progresses, it can cause your blood pressure to dramatically drop in what professionals refer to as “septic shock,” which can kill you.)

Interestingly, the inflammatory response was the worst in those participants who hadn’t prepared well for the extreme endurance events.


Can Running Marathons Be Bad For Your Health?


Proper Training & Preparation

The researchers found that runners who had trained properly had more anti-inflammatory agents in their blood, indicating that the body had built up a healthy immune response to the intestinal changes brought about by the extreme exercise through a gradual training regimen. These anti-inflammatory agents basically strengthened the runners’ immune systems, allowing them to efficiently fight any leaked gut bacteria.

“Extreme exercise” was defined by the researchers as four hours at a time several days in a row, but Costa emphasized that the limits and responses will be different for each individual. He noted that his team consistently began to see significant physiological changes after about two hours of steady exercise (typically running).

To avoid possibly permanent damage to your health, Costa recommends following suggested training guidelines for endurance events. Typically, that means beginning training far in advance and steadily building up to the full event in order to give your body time to adjust. Also, get a health full check before you begin training.

Looking at all the photos posted on social media of smiling marathon participants with medals can make these events look fun, and they can definitely inspire you to challenge yourself. But these are events to be taken seriously and require a lot of hard work.

It’s easy to register for a race, and it’s much harder to stick to the prescribed training regimen. Find a running group or friend to keep you accountable as you prepare for your extreme exercise event. It might also be a good idea to start by participating in a less demanding event, such as a 5K, before committing to anything as extreme as a marathon.


Bottom Line: Keep Exercising Safely

It deserves mentioning that with much of the U.S. population struggling to maintain a healthy weight and keep up any exercise routine, we don’t want to put too much emphasis on exercise being dangerous! Regular exercise has a multitude of benefits that affect not just your health and longevity, but your sleep, your mood, and your productivity, and most of us will never attempt the type of extreme ultra-marathons that researchers have analyzed in this study.

Also, as Dr. Michael Joyner, a physiologist and anesthesiologist at the Mayo Clinic, points out in this co-authored article, the dangers of too much exercise have yet to be proven in any large population-based study, and mortality or longevity rates have not risen with increased participation in these extreme competitions.

We’ll continue to follow the research on this topic as more studies are published.

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