Here’s why.

The right amount of anxiety can improve performance.

Anxiety is an uncomfortable emotion, often fueled by uncertainty. It can create intense, excessive and persistent worry and fear, not just about stressful events but also about everyday situations. There are usually physical symptoms too, like fast heart rate, muscle tension, rapid breathing, sweating and fatigue.

Too much anxiety can be debilitating. But a normal amount is meant to help keep us safe, experts say.

“The emotion of anxiety and the underlying physiological stress response evolved to protect us,” Wendy Suzuki, a neuroscientist and the author of “Good Anxiety,” said.

In her book, Dr. Suzuki explains that managing stress may be more useful than banishing it. According to the Yerkes-Dodson Law, a theory that originated in the early 20th century from experiments on mice, increasing amounts of cognitive arousal, or stress, can improve performance — but only up to a certain point. The theory, represented by a curve shaped like a mountain, shows that after the curve peaks, greater levels of stress cause performance to suffer.

When anxiety is turned up too high, Dr. Suzuki added, it tends to become less useful. The first step in taming anxiety that holds you back is to recognize when you’re feeling overly anxious and try to dial it down.

“My No. 1 tip is to activate the parasympathetic nervous system — the neurons that can slow heart rate and help people feel more calm — by deep breathing,” she said. “It’s a very powerful tool to have in your back pocket.”

Deep breathing can take place anytime or anywhere, she said, whether standing in a line, sitting in class, or, in my case, driving.