Tuesday, 19 May 2009

My aching heart

Feeling as I do at the moment which is to say as fit as a fiddle and happy as I can remember I thought it worthwhile to look ahead at what to expect post raceday and specifically at some of the science on what racing an ironman does to your body.

Obsessed as I am I recognise the impact an ironman race has on my body in the days after. Lets face it you cant help but notice as you struggle down the stairs (and if you dont know what I mean are you sure your racing hard enough?).

There is quite a lot of evidence that, at least in the short term IM has a potentially quite serious impact on your health and hence the very serious advice that you should not race if you have a bad cold. Some colds are caused by viruses that can cause myocarditis (inflammation of the heart) and this is something you really want to avoid. It also reflects the stress doing this event can put your body under thereby making you susceptible to the risk of serious harm from a virus you would normally shrug of after a few days.

So what is the evidence for harm following an IM race. There are two principle effects. The first is that an Ironman reduces the function of your neutrophils (so called white cells that help fight acute infections) and at the same time is associated with quite a marked inflammatory response as part of your immune function response. This inflammatory reaction is what classically happens when we get a serious injury, have an operation or have some other stress put on the body (and can be induced by heat stroke, alcohol poisoning and may other things). The effects of this can be to cause tissue swelling (odema) and pain. It almost certainly occurs in response to the micro trauma associated with 10 odd hours of continuos exercise and the muscle damage associated with this exercise. It will probably be exacerbated by dehydration, heat stress and getting you nutrition so wrong you race prolonged on empty and hence catabolise your muscle a bit more than is strictly necessary. There is alot of science to suggest this state can last up to and beyond 2 weeks post race.

The other principle effects are on your heart. Tests that are typically used to determine whether someone is having a heart attack work by detecting enzymes and proteins released into the blood stream from damaged heart muscle cells. Perhaps the most common of these tests is a test for Troponin T a protein found specifically in cardiac muscle. While it can be raised as a consequnece of other things it is typically raised in response to damage to heart muscle cells. Worryingly this is found to be raised in nearly all IM finishers and when present in what are termed clinically significant levels are usually associated with significant abnormalities of heart function when studied using an echocardiogram. In fact nearly all IM finishers demonstrate some mild impairment of heart function in the first 24 hrs post race. The significance of all of this is not clear. Troponin T levels can also be raised in association with muscle injury and perhaps this is the cause but this would not explain the abnormal heart function.

On a happier note we are no more likely to have knee problems than a non Ironman age matched population.

So in summary ironman takes a toll on your body but this is largely recovered from by 3 weeks. To reduce this train well, race well and recover well.

Finally we will also live longer and find the path to secret super powers foregone by our mortal colleagues.

(sorry but I made that last bit up)

1 comment:

Jevon said...

Bugger the heart, what about my bad back...