INDIANAPOLIS, Ind. — Runners have grabbed their headphones and trained for the CarmelFest Freedom run for months. But does listening to music while running outside put you in danger?
We looked into the science behind your senses.
“There [are] a few different factors–one is attention, of course,” said Dr. Hannah Block with IU School of Public Health. “If you’re distracted by your music or whatever you’re listening to, you’re paying less attention to your environment.”
That could be a recipe for disaster.
While many runners use headphones to motivate them during their workouts, they also understand the dangers that come with doing that.
“I definitely have had some close calls with traffic before even without headphones in,” said Jesse Davis, a local elite runner and president of Indy Runners. “So I’m very alert at every intersection. Especially on the Monon, there are a lot of blind intersections where you can’t see traffic until you get right up on the intersection.”
“I’m kind of paranoid about somebody jumping out and getting me,” said runner Mark Erdosy. “So I like to keep my music just loud enough that I can still hear but low enough so that I can still hear what’s around me.”
According to Block, once you put your headphones in and play music, your sense of hearing can no longer react or get information about where you are or what’s around you. It also shortens your reaction time. She says your reaction time is going to be best when you have both vision and hearing.
“So, if like a car is coming up behind you and you need to jump out of the way, you’re going to be fastest if you can both see and hear the car,” said Block. “That’s because the brain is specialized for multi-sensory perception. So having multiple senses actually gives you better reaction time than either sense alone.”
To demonstrate, Block performed a yardstick test. It’s used to show the difference between reaction time from just hearing something and just seeing something.
First, Block had us hold our hand at a certain point on the yardstick. Then she would randomly drop it and we had to pinch our fingers to catch it as quickly as we could. Next, she had us close our eyes.
Block then used a crumpled piece of paper so we could hear the drop of the yardstick. We had to do the same thing and catch it as quickly as we could. In our experiment, reaction time was quicker when we could just hear the yardstick drop.
“[People] might think that because your ears and your eyes are both stuck to your head, they should be equally close to your brain, so they should be similarly fast,” explained Block. “But what actually affects the speed is the neural pathway itself.”
“So for a signal to get to one place to another place in the nervous system, it goes through nerve cells, or neurons and there’s two kinds of signal transmission,” she continued. “To get a signal from one neuron to the next neuron you have to rely on chemical transmission. So what affects the time delay is how many of those connections between neurons you have in the pathway.”
We also performed our own controlled experiment to see how the yardstick test worked in the real world.
We measured out an area of 120 feet and put a marker at every 30 feet.
Erin Miller is a runner, and she says she always runs with headphones listening to music.
For our test, we had Miller stand still and listen to music at her normal volume. Then we had a driver, honk their horn at each marker. Erin didn’t hear the horn until the car was about 10 feet away from her.
“No way, I heard that clear when you were right there,” said Miller. “[I] didn’t hear anything else.”
Next, we had her perform the test while running. Our driver honked about every 30 feet and again, Miller didn’t hear the horn until the car was about 10 feet away from her.
“I’d like to think I’m aware of this, but obviously this kind of concerns me,” said Miller.
Then we wanted to see how the reaction time is affected if someone is texting or using their phone without listening to music. We performed the same test with Miller standing still and just texting on her phone.
Our driver went 120 feet away and honked their horn at every marker, about every 30 feet. Like with the first test, Miller didn’t hear the car or its horn until it was about 10 feet away.
According to Block, the average reaction time difference between seeing something and hearing something is about a tenth of a second. That’s long enough for a car to pump the brakes about 10 times, a car driving at 50 miles per hour to move 7 feet, or the blink of an eye.
Cars aren’t the only issue out there. There are also people—some who want to do harm. We had our driver switch gears and randomly follow Miller while she was running with her headphones. Her reaction time was significantly slower. She didn’t see our driver until they were less than 10 feet away.
“The only reason I knew that she was behind me was because I had to cross the street,” said Erin.
With our test and the studies, that means in any given scenario, in a blink of an eye a car could’ve hit our test subject, or a person could’ve done harm.
The National Highway Traffic Safety Administration found in 2015, more than 5,000 pedestrians were killed. That means, on average, one person was killed nearly every two hours. That’s not to say they were all distracted by their phones or listening to music, but the study also found since the invention of the MP3 player and smart phone, the number of pedestrian deaths has gone way up.
Distracted walking is a big deal in some places. A town in New Jersey banned texting while walking and those that do could get fined. At one point, streets in London padded some of their lamp posts in case distracted walkers ran into them.
Experts say the safest thing for you to do when you’re outside is to make sure your focus is just getting from point A to point B. This way, you’re not putting yourself or others in danger.