What Fear Does to Your Eyes

There’s a reason cartoons show a character’s eyes growing saucer-size as he lies tied in the path of a train. When you’re scared, your eyes open wider so you can better see and process threats (that swervy rider to your left) and escape routes (the gap that’s opening up in front of him). A 2013 study published in Psychological Science found that people making a “scared face” versus a disgusted or neutral one enhanced their peripheral vision by 9.4 percent.

What Fear Does to Your Neck + Shoulders

Your muscles tense when you’re freaked out, which can wreak havoc on your bike handling. To reduce this, relax your shoulders – performing some shrugs or shoulder rolls should help you loosen up.

What Fear Does to Your Heart

The body releases adrenaline when you’re scared, which triggers a rise in heart rate. It’s part of the “fight or flight response,” says Margee Kerr, a sociologist and author of Scream: Chilling Adventures in the Science of Fear. “It’s meant to prepare us to be strong and fast.”

What Fear Does to Your Hands + Feet

If you’ve ever clutched the bar with clammy hands after outsprinting a menacing dog, you know that a scare can leave your extremities chilled. That’s because your body pulls blood away from the skin to aid major muscles and your heart and lungs. This prepares them to do hard work to help you flee.

What Fear Does to Your Bladder

“So scared I peed myself” is more than just a saying, says Denise Dixon, licensed psychologist with Suffolk Health Psychology Service in New York. An increase in your heart rate can trigger the kidneys to process fluids more rapidly, and voilà, you have to go. That sensation only adds to the anxiety – so maybe take a bathroom break before the jump line.

What Fear Does to Your Skin

Escaping a threat is a lot of work. Your body anticipates this by sweating to help you stay cool. But if you don’t end up sprinting, you won’t need that evaporative cooling – that’s why you may find yourself shivering after a scare.

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