I just thought I would share this question we were asked recently:
“Do you have any data on the incidence of AFib in people who say competed in the Tour de France in past years to see how the risks in this population compare with the public as a whole.”
There is no doubt that I see a lot of people with atrial fibrillation (AFib, AF). Most of the people I see are cyclists. And that makes me think that there is something about cycling that leads to AF. But, it could be a sampling error – all the people who get AF from other sports might go and see someone else. It doesn’t feel like that though. As I supervise the nurse led AF clinic. There are plenty of people who run too in Somerset – I only see a few of those.
Tour De France cyclists are an unusual breed. They may well be genetically different to you and I. Or at least me. And remember, at least (hopefully) until recent times, these riders were (probably) systematically doped. There were probably teams in France doping kids from the age of 11 (according to some of my French contacts), and many domestiques had to take drugs or be dropped. It started with amphetamines in the 1900s.
There are descriptions of arrhythmias in former cyclists (e.g. Europace. 2015 Mar;17(3):387. doi: 10.1093/europace/euu399. Epub 2015 Feb 12.); A left atrial tachycardia is often the start of AF. But, there are no systematic studies that I am aware of. Overall, however, being a TdF cyclist seems beneficial to health however – they seem to live longer at least. See Eur Heart J. 2013 Oct;34(40):3145-50. doi: 10.1093/eurheartj/eht347. Epub 2013 Sep 3 and Int J Sports Med. 2011 Aug;32(8):644-7. doi: 10.1055/s-0031-1271711. Epub 2011 May 26.
That doesn’t mean it’s the cycling though. It could be the diet, the genes, or even the drugs. We perceive drugs as harmful, but that doesn’t mean they are. When the stigma dies down, we should probably try them in the elderly. It might improve the quality of their life – sarcopenia (a loss of muscle) and a loss of cardiovascular fitness really hits the elderly hard in a variety of ways.
I’m afraid that endurance exercise does appear to predispose to AF – at least in men. The paradox is that those who exercise appear to live longer, which can get lost in all the concerns.
So AF may need to be reconsidered as one of those things that happens – like tendonitis, stress fractures and muscle strains (although a bit more serious, in my view).
If I don’t get AF this year, I’ll be doing the Dublin Marathon again in October.