More than half of young female runners suffer harassment, usually from men.

No wonder so many women are running scared — or outraged.

More than half of female joggers over 30 have been harassed, often sexually, according to a Runner’s World report shared exclusively with the Daily News.

The survey comes on the heels of the high-profile murders of three female joggers last summer: Queens resident Karina Vetrano, 30, near Howard Beach; Google employee Vanessa Marcotte, 27, in Princeton, Mass.; and Alexandra (Ally) Brueger, 31, shot in the back in Rose Township, Mich.

The violence has brought the vulnerability of women runners into the spotlight. But beyond anecdotes shared among joggers, there were few hard statistics until now to show just how many women are harassed while running.

Vanessa Marcotte, 27, a Google employee from New York City, was found dead after going jogging in Princeton, Mass.

“That discussion became a safety discussion in a lot of ways, and one tip we had seen going around frequently is that women shouldn’t run alone,” Runner’s World editor Meghan Kita told The News.

“But you wouldn’t give that advice to a man, so why is that appropriate to say to a woman?” she added.

The survey also feeds into the heightened awareness of sexual harassment after a dozen women accused GOP presidential hopeful Donald Trump of lewd behavior toward women — accounts unverified by The News. And many women came forward through social media, sharing very personal stories of being sexually assaulted — after Trump’s hot mic “locker room” tape — using the hashtag NotOkay.

Urban joggers report more harassment than those in rural and suburban areas.

The summer murders led Runner’s World to survey how different a woman’s running experience is from a man’s. Dangerously different, it turns out.

The report found 43% of all women have endured harassment while running, but the number of incidents jumps the younger the runners get. About 58% of those under 30, and half of those 30 to 35, suffered abuse.

And 94% said their harassers were men, the survey found. It’s a stark contrast to just 4% of men reporting being honked at, cat-called, followed or grabbed while on a run.

The New York Daily News published this front page Oct. 27, 2016.

Jogger Kristen Souza, 40, from North Attleboro, Mass., explained to The News that the actions of some men may seem innocent, but, “it is startling, and it forces me to constantly assess my surroundings, looking for possible dangers, instead of truly enjoying my run.”

New Yorker Jae Cameron, 30, told Runner’s World that the whistles and stares make her so uncomfortable, she pauses before every run to ask, “Do I really want to go out there? Do I really want to go deal with this?”

What’s even more frightening is how often the verbal assaults escalate into threatening behavior.

Now many women alter their routes or avoid trails if they are running alone.

One in three women runners reported being followed by a person in a vehicle, on a bike or on foot.

Jennifer Herr, 36, from Brooklyn, told the magazine, “A police car rolled up behind me and blared on the megaphone, ‘Stop running!’ When I turned around, I discovered that they were calling to a man that had been chasing me.”

Juliet Nuss told The News that a stalker followed her in his car for three mornings in a row while she was jogging in Mineola years ago.

(New York Daily News) (New York Daily News)

The Daily News has closely covered the brutal murder of Karina Vetrano since the summer killing.

“He had his pants undone and slowly drove alongside me,” said Nuss, who scared him off by taking down his license plate number and threatening to call the cops. “It was scary, but also made me so angry.”

Erin Bailey, a 25-year-old from Boston, recalled one man who “slowed down his car and followed me for about 30 seconds to a minute, yelling out the window about how I needed to stop running and (have sex with) him.”

This leads to 21% of women toting pepper spray on runs — and 1% even packing a loaded gun. Some 60% will only run in daylight. And 27% tried switching to a treadmill — although they still get tormented indoors. Boston runner Bailey stopped going to her gym after a man said her workout tights would look better off of her.

Women are targeted no matter where they break a sweat. While ladies are harassed more often in urban areas because they literally run into more people, they enjoy relative anonymity over those jogging in small towns, who run the risk of being sexually harassed over and over by the same man. More isolated rural runners also have fewer places or people to turn to for help.

So what happens now?

“The knee-jerk reaction is to share safety tips, which we have learned was the wrong reaction, because women already do know how to ‘stay safe,’ and they follow the recommended behaviors,” Kita said. “This is a much more complex societal problem that doesn’t only affect women who run — it affects women who go outside for any reason.”

She hopes this survey will spark a conversation to help male runners understand what their female training counterparts experience, and for the public at large to become aware of the dangers dogging women joggers’ steps.

SHARE YOUR STORY: Have you been harassed on the run? Tweet your encounter at #WomenRunningScared or email runners@nydailynews.com to tell us your story.