Hayden Roulston. Photo / APN
Sir Peter Snell is the latest sporting great diagnosed with heart problems.
Although sports physicians say there is no established link between exertion and heart problems, there is emerging evidence that extreme exercise endured by athletes in events like ironman races may be harmful.
Rower Rob Waddell has atrial fibrillation
and cyclist Hayden Roulston has arrhythmogenic right ventricular dysplasia.
Sir Richard Hadlee was born with an abnormal heart beat and had surgery in 1991, a year after he retired from playing cricket.
Sports physician Dr Dale Speedy said yesterday there would be no connection between Waddell's and Roulston's disorders and the punishing exertion of rowing and cycling.
"There's no published evidence of an association between hard exercise and those conditions."
But both Dr Speedy and Professor Harvey White, the director of coronary care at Auckland City Hospital, point to emerging evidence of tiny areas of cell death in the heart during prolonged, extreme exercise. The consequences are unclear.
"They may be sites for abnormal heart rhythms in later years," said Professor White. "It's a hypothesis."
Dr Speedy said only one study was published, relating to ultra-triathlons.
The Taupo ironman involves a 3.8km swim, 180km cycle ride and 42km run. Some competitors take 10 to 15 hours to complete it.
Another study, not yet published, found the heart arteries of long-term marathon runners in the US had increased calcified plaque, putting them at more risk of a heart attack.
