PHOENIX, Arizona, February 7. THE University of Portsmouth released news of an interesting ongoing study that investigates why apparently healthy athletes die during open water swimming competitions.
The death statistics are staggering in triathlon competitions: 30 of the 38 deaths that happened during American triathlons (between 2003-11) happened during the swim portion. No pre-existing health conditions were recorded amongst those who died.
One theory being tested by Professor Mike Tipton at the University states that the deaths were caused by a phenomenon called Autonomic Conflict. When the body's cold shock and diving responses are activated at the same time, the effect can cause cardiac arrest. Cold shock causes hyperventilation by speeding up heart rate, whereas diving response conserves oxygen by slowing down heart rate.
“Normally the two responses don't happen at the same time, but when they do, the heart can go into abnormal rhythms,” Tipton wrote in an online commentary for the British Journal of Sports Medicine.
These two opposing responses are highly likely to happen during open water swimming competitions. Anxiety and competitiveness heighten the chances of cold shock when a person is submerged in cold water. Extended breath holding, facial wetting and water entering the nasal passage activates the diving response.
In a stressful competitive situation — like the “crowd” in open water swimming events — athletes are more likely to experience situations that may trigger the two responses happening simultaneously.
Read the full story at: University of Portsmouth News