It may seem no more than a catchphrase, but scientifically speaking, Red Sox fever is real.
And with the team returning to Fenway tonight after two losses against the Yankees, the effects are growing more unpleasant. Research shows that the dread of repeated disappointment -- a feeling familiar to even casual Sox fans -- can turn an iron stomach queasy, a cheery person into a grouch, and can trigger such strong waves of shuddering apprehension that the most sedate fan may impulsively jump up and flick off the television.
Perhaps worse news: It's contagious. Emotions can spread quickly from person to person, so it's only a matter of time before the tense, drawn faces in coffee lines or on the T spread to those who think they are immune.
''If you see someone who suddenly looks very much afraid, that will sort of go to your emotional brain and suddenly you'll have a little twinge," said David H. Barlow, director of the Center for Anxiety and Related Disorders at Boston University. ''When you get a number of people increasingly uptight and focused on future threat . . . it will get others' attention."
Researchers have long known that fans react dramatically to sports events, but the social psychology of sports fans has recently evolved into an academic field of its own, giving scientists a clear picture of what could happen to Sox fans next.
If the Red Sox win tonight's game, the emotional high could temporarily wipe out the effects of Tuesday's and Wednesday's crushing defeats. A third straight loss might contribute to a psychological condition known as ''learned helplessness," which affects people whose hopes have been repeatedly dashed, causing them to sink into fatalism or resignation -- ''a state that may describe some of the Red Sox fans," Barlow said. If tonight's game is rained out, fans' anxiety will simply be delayed, possibly increasing stress levels.
These sports-triggered responses have their root in human evolution, says Dr. Michael Craig Miller, editor in chief of the Harvard Mental Health Letter. An individual's survival once hinged on being identified with a group of people, and on that group's ability to recognize the enemy clearly. And being part of that group, even if it's a losing one, can make people feel better.
''We join groups to enhance our self-esteem and decrease isolation. It's a way to connect . . . it's tribal," said Miller. Even the anticipation and anxiety fans are feeling have their root in evolution, as bodies prepare to either confront or run from a threat -- a response known as ''fight or flight."
In some circumstances, this kind of apprehension can be eased by taking action. For instance, voters feeling anxiety as the presidential election approaches can redirect their energy by joining a campaign, giving them a sense of accomplishment and evolutionary usefulness.
But that option doesn't exist for Sox fans -- whose worry, researchers say, is ''nonproductive." Though fans can sink their energy into studying the game and players, Miller points out, they have no influence on a game's outcome and can't effectively work out that anxiety, save for letting loose with a cheer or a boo. ''We shouldn't fool ourselves to think it's our personal victory [if they win] or our failure if they lose," he says.
In slow periods during playoff season, when there are no Red Sox games, fans may begin to feel sad, fatigued, anxious, or irritable, as their body gets worn down with anxiety or anticipation. They may have trouble digesting food or sleeping. Then once a game starts, people undergo intense physical changes as they react to the scene before them.
By monitoring fans watching a variety of sports events, scientists have documented a range of physical reactions. Fans sweat. Muscles tense. Blood pressure increases and, if things get really heated, spectators' breathing becomes rapid and shallow. Len Zaichkowsky, head of the sport psychology program at Boston University, says he once measured a fan during a hockey game whose pulse reached 180 -- the heart rate of a professional runner during a competitive race. While such bursts of reaction and longer-term sports anxiety tend to be harmless, some doctors note it may exacerbate existing heart problems.
The intensity can also play out in less measurable ways. In the Cambridge apartment of Liz Tempesta, a Yankee fan, and Jay Cannava, a Red Sox diehard, tension is rising. During Tuesday's game there was virtually no conversation between them: Tempesta uttered one sentence and Cannava didn't respond. Instead, he clutched his lucky bat and methodically beat a couch cushion as the Red Sox slid into defeat.
''He's very mild-mannered," said Tempesta. ''But the last two years during playoff season have been tough, and this year is worse."
Other research shows that even if the Red Sox were to win the pennant in four straight games, their fans' happiness would probably be fleeting. First there would be the World Series to worry about, and even if the team were to win that -- delivering a burst of short-term euphoria -- people's long-term happiness will remain largely unaffected. ''Happiness has a much shorter half-life than disappointment," says Miller, although he admits that he is hoping for that euphoric burst.
Given the Red Sox' history -- and the level of grousing every time another season ends in defeat -- perhaps fans should get busy practicing a different emotional coping strategy: forgiveness.
''The value of forgiveness is after you feel pain you let it go," said Frederic Luskin, author of Forgive for Good and head of the Stanford University Forgiveness Project. By forgiving, he says, fans can then become optimistic about the next year's prospects.
Luskin also offered a lesson for fans: ''Never need something for your happiness that you have no control over," he said. ''It's a very vulnerable position."
Beth Daley can be reached at email@example.com.