Episode 174. Volume Exercise and the Heart with Dr Maria Brosnan
The Greek messenger Pheidippides famously ran 42 kilometres from Marathon to Athens delivering news of victory in battle before dropping dead, still a young man. Pheidippides was undoubtedly fit and an accomplished runner as he had been a Greek herald messenger his entire life. Was his untimely death due to excessive exercising or unforeseen preexisting cardiac risk factors? This stand-out story mirrors the sad death last year of champion athlete and Queensland iron man Dean Mercer, aged 47 years, from an acute cardiac event after an early morning swim session. Was his death a consequence of his extraordinary training schedule or preexisting cardiac disease? The famous Australian Carney sisters were both forced to retire from world triathlon competition and their elite standing with life-threatening cardiac disease, similar to world champion triathlete Greg Welch. Notable athletes such as American marathon runner Ryan Shay succumbed from a fatal cardiac event at 28 years during Olympic Marathon trials and athlete authors Christopher McDougall known for his book ‘Born to Run’ died alone on a trail run in New Mexico aged 58 years similar to Jim Fixx who wrote ‘The Complete Book of Running’ and died in 1984 at the age of 52 from an acute cardiac event. These notable cases raise questions about the insidious impact of elite endurance sport and volume exercise and raise concerns about cardiac rhythm disturbances and coronary arterial plaque rupture, as well as chronic inflammation in a condition some refer to as “Athletes’ Heart”.
As compelling as this diagnosis may seem, the proposed condition “Athletes’ Heart”, however, is not widely accepted and indeed, quoting Andre La Gerche, who is an expert sports cardiologist at the Baker Heart and Diabetes Institute, there is no proven link between endurance sport and sudden death. To the contrary, Athletes live longer. Endurance athletes and gold medallists live the longest; however, endurance athletes are about 2-5 % more likely than the general population to develop heart problems, including rhythm disorders such as Atrial Fibrillation”.
Dr La Gerche urges us to remember the importance of separating public health from individual risk and reminds us that exercise in all forms reduces the risk of cardiovascular disease and diabetes and extends life. Any individual can have a heart attack; there are 20,000 deaths from heart disease per year in Australia -one every 10 minutes. Common things happen commonly, and about 1 per 100,000 people die of heart attacks during marathons; no conclusion can be drawn as a preexisting condition in such cases was likely.
The question remains whether moderate exercise should be the goal with caution for those entering elite high-volume endurance training regimes. As noted, studies are progressing, but to answer some of these questions, I was joined by cardiologist Dr Maria Brosnan. Maria is an elite athlete herself, having competed widely, and has a strong interest in arrhythmias as well as cardiac physiology in elite athletes. She works at St Vincent's Heart Centre and The Baker Institute as well as the National Centre for Sport Cardiology. She serves as a consultant for Tennis Australia, The AFL draft, Rowing Australia and several professional cycling teams. Please welcome her to the podcast.
References:
D Maria Brosnan: St Vincent’s Heart Centre, www.stvheart.com and nationalsportscardiology.com
Competitive Sports and the Heart: Benefit or Risk ?. https://pmc.ncbi.nih.gov
Athletes and Heart Disease: Why Does It Happen? www.mountelizabeth.com