Brazil's cataclysmic World Cup loss to Germany broke the heart of a nation.
But for some fans, the emotional anguish may have felt all too real – resulting in heart attacks that not even the U.S.'s star goalie Tim Howard could stop.
A 2008 analysis published in the New England Journal of Medicine found that cardiac events skyrocketed during World Cup matches.
Researchers looked at data from hospitals around Munich during the 2006 games held in Germany. They found that the number of cardiac emergencies more than doubled on days when Germany was playing in World Cup matches compared with days when the German team was idle and also a control period when no matches were played. About 43 cardiac events were seen on German match days compared with 18 on the non-match days and 15 daily during the control period.
The emotional stress during matches, the paper argues, increases a fan's risk of suffering a heart attack.
"Soccer is engaging, but if you're on the losing side you can feel helpless," says Dr. David Spiegel, a psychiatrist from Stanford University who specializes in stress and wasn't involved in the 2008 study. "That combination of a time limit and the difficulty of overcoming being behind makes it a stressful sport to watch."
Stress, Spiegel tells Shots, changes what's circulating in the bloodstream.
When someone watches a particularly exciting or emotional match, such as the United States' defense in the net against Belgium's onslaught, the body releases adrenaline and other hormones into the bloodstream.
The plaques can rupture. The body creates blood clots to patch the damaged arteries. But the clots can block oxygen-rich blood from reaching the heart, causing a cardiac attack.
"It's not like this could happen suddenly in anybody," Martin tells Shots. There has to be underlying disease, such as high blood pressure and diabetes. Unhealthful habits, such as sitting in front of the TV or computer for too long, could exacerbate the chances of suffering a cardiac attack during a game.
"We don't know what day someone will have a heart attack," Martin tells Shots. But heart attacks are more likely to happen in people with risk factors for them.
Already in Brazil, a 69-year-old man suffered a heart attack in a bar while watching the nail-biting penalty kick duel between Brazil and Chile. The man, who had diabetes, died two hours after being brought to the hospital.
Martin said he wasn't surprised that soccer matches could trigger cardiac events in fans. He was surprised however by the magnitude of the trigger reported in the paper about the German World Cup experience.
Still, some researchers are skeptical about any connection between soccer games and cardiac events.
Epidemiologist Francesco Barone-Adesi says that any evidence of soccer-induced heart attacks disappears at the population level. He authored a 2010 meta-analysis titled, "It is just a game: lack of association between watching football matches and risk of acute cardiovascular events."
He analyzed 10 previous papers that looked at associations between heart attacks and World Cup games in people living in Belgium, France and Australia. In his analysis, which had included the German study, he found no link between World Cup matches and heart attacks.
"The German study was an outlier and inconsistent with all those other studies," he says. "It's telling a different story."
He also conducted his own study that looked at death certificates in Italians during the 2006 World Cup and found no connection between watching soccer games and heart attacks.
If the results obtained by the German study are accurate, then Barone-Adesi says that "would mean that watching a football match is the strongest cardiac event trigger found so far," he says, adding, "that's just not plausible."
But cardiologist Robert Kloner, of the University of Southern California, says that the triggers that the German study found can't be totally ignored.
"Look, there's a signal here in this study," Kloner tells Shots. "You're not going to see it in all games. It depends on the patient. If he says, 'I feel my heart racing,' then that's concerning."
In 2010, Kloner published a paper titled, "Sporting Events Affect Spectators' Cardiovascular Mortality: It Is Not Just a Game." His study looked at Super Bowl games in Los Angeles in much the same way that previous studies looked at soccer games. He found a small, but statistically significant, increase in heart attack-related deaths following the games.
After reviewing the scientific literature, Kloner says that watching sporting events, such as soccer matches and Super Bowls, may trigger heart attacks in people prone to them. But, he cautions, "These are correlations, you cannot call them causative."