"It appears that if your team is playing there is a higher risk of heart attack. If you are hosting a tournament there is a greater risk, and if the game is close there is greater risk as well," Dr Olsen said.
Dr Elliott said a small number of people had gone to Christchurch Hospital with heart problems during RWC games.
In 1999, the Herald tracked a reporter's heartbeat as he watched an All Blacks-Springboks test. From a resting rate of 79 beats a minute, the reporter's heart shot to 115 beats a minute when Pita Alatini scored a try - and to 130 beats a minute when Jonah Lomu fumbled a scoring opportunity.
"I felt exhilarated, but I wasn't conscious that my pulse was racing," the reporter said later.
Tucking into a halftime feed might not be helping either.
"Factors such as diet are also being assessed because dietary habits can change during the World Cup, and probably not for the best either," Dr Olsen said.
The data had not been fully analysed but once it had been, it would reveal if there were differences between men and woman watching the games, and those watching at the ground as opposed to at home.
The research will also assess the national database of cardiac events, including heart attacks, to look for increases in national rates when the All Blacks play.
