"The emotional stress of loss and/or the intensity of a game played in a high profile rivalry such as the Super Bowl can trigger total and cardiovascular deaths," ABC Online quoted Dr Robert Kloner, a professor of medicine at the University of Southern California, as saying.

"In contrast, a win in a lower intensity game may actually have a favourable effect on mortality," he added.

According to Kloner, fans who get excited during sporting events and have risk factors for heart disease should consult their doctor before a big game.

Drugs such as beta-blockers, aspirin or anti-anxiety drugs could help them, as could relaxation exercises, such as deep breathing, he says.

"I'm not suggesting that people not watch the Super Bowl. People should be aware of this and I suspect it applies to other sports as well," he added.

To reach the conclusion, researchers analysed data on all-cause death rates from Los Angeles County for the day of the game and the following two weeks after the game, and compared deaths for similar periods in January and February for 1980 to 1983 and from 1984 to 1988.

Researchers found a 22 percent increase in circulatory deaths and a 17 percent increase in overall deaths in the Super Bowl-losing year compared to control years.

Kloner says the 1980 game was a particularly intense game with the lead changing seven times. The Rams also were in their first Super Bowl.

"These factors may have made the fans more emotionally involved," Kloner says.

In contrast, Los Angeles County saw a 6 percent decrease in deaths the year the Raiders won, the study found.