headerphoto

Overdose of Exercise May Be Fatal

video




Thanks to my cousin Jeremy Tan for sharing this. As the saying goes "Too much of a good thing can be bad".


NARRATION
The endurance athlete represents the pinnacle of elite fitness: extraordinary stamina, extreme willpower and a grim determination to push the body past its pain barrier. But disturbing new evidence suggests such extreme levels of exercise may be damaging to the heart, and in some cases, fatal.

Emma Carney
I was a bit of a notoriously hard trainer in a week I'd be swimming 30/35 km . . . biking 350/400 km and running around 100 km.

NARRATION
Two time world champion triathlete, Emma Carney, was virtually unbeatable until an unexplained drop in her performance.

Emma Carney
I dropped out of the top three, dropped out of the top five and then I started dropping out of races altogether.

NARRATION
But it was a brush with death which finally brought Emma's career to a standstill.

Emma Carney
It was a swim training session, I was finishing the session off and I suddenly felt really tired and fatigued. I felt my heart racing in my chest and I thought I was having a panic attack to cut a long story short I was actually going into cardiac arrest.

NARRATION
Emma was diagnosed with an exercise induced heart disorder.

Tanya Ha
Exercise has remodelled her heart to the point where it beats abnormally, putting her at risk of sudden cardiac arrest.

Prof Richard Harper
This was obviously a very unusual case, because here's a very fit, healthy young person who's been an elite athlete and she's got a very serious ventricular arrhythmia which usually occurs in much older people. We did an echocardiogram which showed that the right ventricle was enlarged and not contracting as well as it should that led us to do a cardiac biopsy.

NARRATION
Professor Harper was looking for signs of fatty infiltration, which occurs in the genetic version of Emma's condition but instead he found evidence of scar tissue, which indicated some kind of damage to the heart.

Prof Richard Harper
There was clearly something going on in the right ventricle, perhaps related to intense athletic activity.

NARRATION
At the same time Dr Andre La Gerche, a marathon runner himself, was starting to uncover evidence the heart could be damaged by endurance racing.

Dr Andre Le Gerche
We were able to take blood tests very soon after the athletes had crossed this finish line. We found that there were increases in troponin a marker of injury to the heart muscle. We also did a heart ultrasound. To our surprise we found that the left ventricle was minimally affected.

NARRATION
But the right ventricle showed big changes. Swollen and beating weakly, the longer the race, the more abnormal it became.

Dr Andre Le Gerche
Almost simultaneously a paper came out of Europe suggesting that athletes presenting with serious arrhythmias had serious right ventricular abnormalities.

NARRATION
The study looked at 46 athletes with abnormal heart rhythms in all but one athlete the arrhythmia arose from the right ventricle. Within five years, nine of the athletes had died suddenly.

Dr Andre Le Gerche
Up until that point we thought that these arrhythmias, even though they looked serious, could never be life threatening. We've also found a number of athletes that in the year prior to the onset of arrhythmia's have reported quite a decline in performance and we think the two are linked.

NARRATION
Andre's team is trying to work out why the right ventricle is affected by extreme exercise.

Dr Andre Le Gerche
Intriguingly what we've found is that the wall stress in the right ventricle increases dramatically during exercise.

NARRATION
It's most likely due to what's happening in the lungs. While large blood vessels can open up in the body to allow increased blood flow during exercise, vessels in the lungs are less able to adapt and pressures rise.

Dr Andre Le Gerche
That blood pressure has to be provided by the right ventricle the work increase in the right ventricle doubles, and so it works much harder.

NARRATION
For an elite athlete like Emma who pushed herself to the limit this could have been fatal. Emma now wears a defibrillator which can shock her heart back into normal rhythm.

Dr Andre Le Gerche
We believe very strongly that moderate exercise and normal exercise are of very established and proven benefit. So if we can establish what it is that can be a problem in a minority of athletes then we can make exercise truly safe for everyone.

NARRATION
So in case you are thinking this research is a good excuse to be lazy well The National Heart Foundation still recommends at least 30 minutes of moderate exercise each day so exercise is still important for a healthy heart.


Source: http://www.abc.net.au/catalyst

People who read this post also read :



0 comments: