The following report by medical editor Marilyn Brooks first aired on Channel 4 Action News at 5 p.m. on Jan. 13, 2006.

---

As a college athlete, Allison Bertke said she knows all about performing under pressure.

Tests really make her feel the heat. There's a lot riding on her grades and when the exams begin, her stomach turns to butterflies.

"I know if I don't score well on my exam, it will drop my grade in my class, and the grade dropping will drop my overall GPA," said Bertke.

While it's all too common to get stressed out over things such as tests or public speaking, researchers say it's also common that stress can do more harm than good.

In fact, stress can actually make it harder to think on your feet, researchers say.

"What we found was that the stressor, again, significantly impaired their ability to solve problems flexibly," said neurologist Dr. David Beversdorf.

Beversdorf's study, presented at the annual Society for Neuroscience meeting, measured how stress affects our problem-solving abilities.

He found that the scores of people who took tests after doing something stressful, such as giving a speech or watching a violent movie, dropped nearly 15 percent.

A related study suggests that in extreme situations, a beta-blocker medication used to treat high blood pressure may help some people.

"Propranolol eliminated the effect of stress. If they were under stress, but had taken propranolol, then they performed as if they had no stressor," said Beversdorf.

But the drug is no magic bullet. Beversdorf said more research is needed to know exactly how stress affects thinking and how medication may help.

Meanwhile, people like Allison have to beat it the old fashioned way -- block out enough time to study before an exam, and distractions during that exam.

Chronic stress is considered by doctors to be a major destroyer of health in the western world.

In the United States, at least three out of four visits to the doctor's office are stress-related, ranging from heart attacks to nervous breakdowns.