Heat can make road rage worse. Here's how you can pump the brakes on it.

WASHINGTON — It's summer. The sun is blazing and behind the wheel, some tempers are flaring. It doesn't take much on the road to get horns honking, especially when it's hot outside. Research has long linked a correlation between violence and heat. 

In a classic study from the 1980s, researchers found that drivers get more aggressive on hotter days. In the study, a car would stop and sit through a green light cycle without moving. Who wouldn't honk at that? But it's the type of honk that researchers were looking at. 

When temperatures were below 80 degrees, drivers gave a light short honk to nudge the other driver along. But when temperatures were above 90 degrees, drivers really leaned on the horns. They honked longer and made unfriendly hand gestures. This was especially true for drivers with the windows down, and presumably didn't have air conditioning. 

Another study published by the National Institutes of Health found that deadly crashes in the U.S. increased 3.4% on heatwave days between May and September. 

How Our Bodies Respond to Stress Like Road Rage

So what's going on? When we are stressed by experiences like road rage, we go into "Flight or Fight" mode. Harvard medical experts say our hearts pound faster, we breathe faster, muscles tense up, heart rate and blood pressure also go up. More oxygen flows to the brain so you're more alert. Our bodies also get an extra boost of cortisol, a stress hormone to help us stay on high alert. All of this is designed to get us out of a life-or-death situation, not necessarily a traffic jam. 

Chronic stress can increase the risk of heart attack and stroke and lead to other health problems like high blood pressure, anxiety, depression, addiction, and obesity. Experts at Wharton found that high levels of cortisol may also impact our ability to make good choices. 

Create A Calm Car Climate 

So what can we do? Cool off and pump the breaks on road rage. Some experts recommend creating a stress-free car climate by playing calming music, put a picture of a loved one on your dashboard, hang a peppermint or cinnamon scented car freshener in your car as these scents have been shown to lower driver frustration.   Deep breathing was also recommended.