At its most basic level, “fear is a relatively normal response to situations that commonly result from a loss of control or perceived danger,” says Jon Woozley, Physician Assistant with Utah Valley Heart and Lung Surgical Associates. “It’s a response that has kept the human race alive through its entire history.”

So what causes fear?

When we are frightened, the nervous system responds with a “fight or flight” response. This causes a number of changes in the body, helping us stay alert and ready to respond to perceived or real threats to our safety.

One of the natural responses to fear is the release of two chemicals that stimulate the heart: epinephrine and norepinephrine. These chemicals result in increased blood pressure and increased heart rate, which prepares the body to perform its natural defensive role when threatened.

Is fear healthy or unhealthy?

“Fear is a normal response,” says Woozley. “All humans and most animals experience fear. This response can be paralyzing for some people. Others can learn to be super efficient and effective with this response.  Many examples are in the stories of numerous Medal of Honor recipients.”

So what’s the correct dose of fear?

Well, there’s no set standard. Just as people perceive fear and threats differently, their take on fear will vary. The goal is to remain functional without overexposure to the stress related to fear.

It’s not clear what the long-term effects of fear are, but long-term stress can take its toll on the heart and the mind. Our response to fear lasts until the danger has passed, but our bodies often respond in similar ways to stress, particularly lasting mental stress. The increased blood pressure levels and pulse rates resulting from mental stress put a strain on the heart and can be detrimental to overall health.

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So while fear may be temporary, and can get the heart pumping and the mind racing, long-term stress may cause lasting health problems.

How can I be better at responding to fear?

Because fear affects the heart, it likely won’t come as a shock that improving your body’s ability to respond to fear comes down to simple heart-healthy behaviors like proper diet, regular exercise that gets the heart pumping, and reducing stress.

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“A healthy heart will be more effective and efficient within the fear pathway,” says Woozley. “It will improve initial response to fear as well as recovery from fearful episodes.”

So go ahead and enjoy that scary movie. But maybe try getting in some exercise before.