Run for Your Life!

by Lewis Shi, MD

Sudden unexpected death during road races is usually due to underlying and often unsuspected heart disease.  Such catastrophes often attract substantial public attention, and there is some uncertainty about the risk associated with training and competition.  One study estimated that the incidence of sudden cardiac death in unscreened men during exercise is 1 in 280,000 per year. Another study looked at all US marathon finishers from 2000 to 2009, and found 28 people died during or within 24 hours of the race, out of 3.7 million participants (0.75 per 100,000 people). (Matthews et al in AJSM 2012).

Some possible causes of death include:

  • Coronary artery disease – Coronary arteries provide blood supply to the heart muscles.  Abnormalities due to coronary plaques or congenital differences can decrease blood flow and oxygen supply during exercises.
  • Hypertrophic cardiomyopathy – Patients with this genetic disease have larger than normal left ventricle, or in particular the septum that divides the ventricles.  The hypertrophied septum can obstruct blood flow, leading to sudden death. 
  • Cardiac arrhythmias – Abnormalities of the heart electrical conduction system can lead to fatal arrhythmias; causes include genetic abnormalities or viral inflammation of the heart muscle (myocarditis).
  • Drugs – Some deaths can be linked to performance enhancing agents such as anabolic steroids, diet medications, and erythropoietin. 

Notably under-training does NOT increase one’s risk of cardiac event during a race.  There is no significant evidence that pre-screening is useful at preventing sudden cardiac death at the population level; however, physical exam by a primary care physician and possible referral to a cardiologist can detect anomalies.  Runners with family history of cardiac disease, or sudden cardiac death, and those with symptoms (chest pain, shortness of breath, etc) during training or racing are certainly recommended to speak to a physician.

Exercising (running in particular) is still far better for one’s health than being sedentary.  Active individuals are much healthier and have better chance of surviving a cardiac event than sedentary individuals.  

Lewis Shi, MD, is an orthopaedic surgeon who specializes in shoulder and elbow injuries. He is also an ironman and has completed 18 marathons.