ANXIETY and competitiveness could be behind the deaths of athletes swimming in triathlons, according to scientists in Portsmouth.
A study is being launched to establish why more healthy competitors die during the swim than the cycling and running sections of the sport.
Of 38 athlete deaths in American triathlons between 2003 and 2011, 30 occurred during the swim.
Professor Mike Tipton, of the University of Portsmouth’s department of sport and exercise science, believes the deaths could be caused by a phenomenon called autonomic conflict, where the body’s cold shock response and diving response are activated at the same time.
The cold shock response speeds up the heart rate and causes hyperventilation, while the diving response slows the heart rate down to conserve oxygen.
The cold shock response can be caused by anxiety, competitiveness and the body entering cold water.
Writing for the British Journal of Sports Medicine, Prof Tipton said: ‘Normally the two responses don’t happen at the same time, but when they do, the heart can go into abnormal rhythms, which can cause sudden cardiac death.’