(CNN)Jessica Rudd has been running for 10 years and says she gets rude comments or some other form of harassment from men at least once a week.
The Atlanta Ph.D student runs 30 to 35 miles a week -- more if she's training for a big race -- and often while alone. When someone harasses her, she grits her teeth and tries to ignore them.
"It's hard to always tell if it's meant to be funny ... but almost always it comes off as sketchy," Rudd, 33, told CNN.
There's a world of difference between catcalls or wolf whistles and the fatal violence that befell Mollie Tibbetts, who disappeared last month after going out for an evening run in Brooklyn, Iowa. Authorities say her suspected killer, Cristhian Bahena Rivera, followed her in his car as she ran along a country road before assaulting her.
But Tibbetts' case has raised safety questions for women runners, a startling number of whom say they have faced harassment, or worse, from men who seem to view an athletic woman in shorts or jogging pants as an invitation for lewd or frightening behavior.
Survey finds widespread harassment
In 2016 Runner's World asked its readers, "How often, if ever, does a stranger whistle at you, comment on your body, needlessly honk at you, or give you other similar unsolicited sexual attention?"
Forty-three percent of women runners said they sometimes, often or always experienced such behavior. Only 4% percent of men did.
According to court documents, Rivera said in an interview that when he approached Tibbetts, she pulled out her cell phone and said she was going to "call the police" and that made him get angry.
CNN contributor Symone D. Sanders argued this week that the main safety issue in the Tibbetts case was not Rivera's status as an undocumented farm worker from Mexico but his "toxic masculinity" and the suspect's unwillingness to take no for an answer.
The Runner's World survey found that violence against women joggers is rare. Only 3% said they had been grabbed, groped, or otherwise physically assaulted -- but that doesn't make the other behavior less frightening.
-- 30% of women said they have been followed by a person in a car, bicycle or on foot
-- 18% said they have been sexually propositioned
-- 5% said they have been flashed
And 54% of women said they were concerned at least sometimes while running, or getting ready to run, that they could be physically assaulted or have unwanted physical contact.