Exercise is a very effective way of preventing a heart attack, but can it also cause one?

It is called the exercise paradox. A wealth of studies prove that regular exercise reduces your risk of a heart attack and yet every time that you exercise, your risk of a heart attack is higher than had you stayed on the couch.  Christine Albert and her colleagues in Boston, USA reported that the risk of dying during a single bout of strenuous exercise was exceedingly low (1 death per 1.5 million bouts of exercise) but that the risk was 17 times higher than had the person not exercised1. However, the most important statistic was that the risk of dying during exercise increased 74-fold in those who rarely did any exercise as compared with a 10-fold risk in those who did regular exercise.

This ‘paradox’ can be hard to get your head around but it needs to be considered when we see the rare cases of high profile people having heart attacks during sport.  The simple truth is that these events are massively outnumbered by the unfit people who die when having to hurry to catch the bus.

The secret is to get fit in a gradual and incremental manner and avoid exercise which is ‘out of the blue’ in terms of intensity or duration. With a sensible training program you can get the massive benefits of exercise (fewer heart attacks, fewer cancers, lower blood pressure and diabetes) whilst minimising the very small risks.  Exercise is perhaps the only treatment that makes you feel better and live longer, as former Boston Marathon winner Amby Burfoot nicely summarised “I run to add life to my years, not just years to my life”.

Is there any way that we can reduce the risk of an exercise-induced heart attack even lower?  This is an area of active research interest at the Baker IDI Heart and Diabetes Institute.  There is a test in which calcium can be measured in the heart arteries (“coronary calcium scoring”) which is showing promise in identifying those people who may be at higher risk of a heart attack. We are currently investigating whether using this test can select people who are more likely to benefit from more intensive preventative therapies. Contact us to see if you quality to participate in the  Caught-CAD study.

Associate Professor Andre La Gerche
Head, Sports Cardiology
Baker IDI Heart and Diabetes Institute

References:

  1. Albert CM, Mittleman MA, Chae CU, Lee IM, Hennekens CH, Manson JE. Triggering of sudden death from cardiac causes by vigorous exertion. N Engl J Med 2000;343:1355-61.

The information in this post is brought to you by our partner Baker IDI Heart and Diabetes Institute. Found out more about this study at https://www.bakeridi.edu.au/health_services/clinical-trials/CAD/

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