(CNN) For years, Julie Flygare kept her condition private. She hadn't liked people's reactions on the occasions when she had opened up and shared her story. People thought it was a joke or not important.
In 2007, Flygare, then a 24-year-old law student, was diagnosed with narcolepsy with cataplexy, a neurological disorder that causes chronic sleepiness and, in her case, symptoms of brief episodes of muscle weakness triggered by strong emotions.
But Flygare turned the situation on its head. The Ivy League grad went on to earn her law degree from Boston College, where she studied health law and health policy.
Now, Flygare is 33 and lives in Los Angeles, where she works full-time as a marketing manager and heads her nonprofit, Project Sleep, aimed at raising awareness about sleep health and sleep disorders.
"After all this studying that I did, I kind of felt like we were caught in this catch-22, where we don't like these misperceptions and these jokes that people make about narcolepsy, so then we're not sharing that we have it," Flygare said. "How do we break that cycle?"
Narcolepsy affects every decision Flygare makes: when she eats, when she drives, when she works, when she sleeps. She takes medication twice a night and stimulants during the day. This means, for example, planning meals strategically to maximize her wakefulness for important tasks, like driving, since eating can contribute to her excessive daytime sleepiness. People with narcolepsy often don't sleep through the night.
But she didn't want the disorder to define her boundaries. So Flygare went after her toughest physical challenge yet: LA's Griffith Park Trail Marathon.
"I'd say that having narcolepsy on an everyday basis is much harder than running a marathon," Flygare said.
Narcolepsy affects about one in 2,000 people in the United States, according to the Division of Sleep Medicine at Harvard Medical School. It's rare, but experts say it's probably underdiagnosed.
"What's generally said, and it's a very hard thing to prove, is that only about half of people with narcolepsy are actually diagnosed as such," said Dr. Thomas Scammell, a professor of neurology at Harvard Medical School and a physician at Beth Israel Deaconess Medical Center in Boston.
"Part of the challenge is because narcolepsy isn't a common disease and because most doctors get very little training in sleep disorders, our concern is that a lot of times, when people go to their primary care doctor, neither the patient nor the doctor may really have an appreciation of what are the right questions to ask to lead to the diagnosis," Scammell said.
There are two major types of narcolepsy: narcolepsy with cataplexy and narcolepsy without cataplexy.
Narcolepsy causes relentless sleepiness. Cataplexy is episodes of muscle paralysis triggered by emotions, like surprise or laughter. Symptoms typically start between the ages of 10 and 20, develop over several months and last a lifetime.
Cataplexy started when Flygare was 21. She consulted a few doctors about her symptoms, but they didn't know what it was.
Finally, she saw a sports therapist who asked whether her knees ever buckled. They did.
"The sports therapist said 'I think I've heard of that. It's called cataplexy,' " Flygare recalled. "As soon as I read the description of cataplexy, I knew that's what was happening, and then I found out that was a symptom of narcolepsy."
After a 24-hour sleep study, Flygare was officially diagnosed with narcolepsy with cataplexy.
"Narcolepsy has as much impact on people's lives and on their quality of life as diseases like epilepsy," Scammell said. "Many people who have narcolepsy say that they feel as sleepy as you or I would feel if we'd been up all night the night before; literally, it's a struggle to get through the day.
"It can be very limiting, especially when people are not on optimal treatments and haven't learned ways of really living with it in a healthy kind of way. The unfortunate truth is, we don't have any good ways of preventing the development of narcolepsy now," Scammell said.
But narcolepsy is manageable, and people with narcolepsy can lead "full and rewarding lives" thanks to different treatment regimens.
Flygare usually takes about a 15-minute nap every day. "I have to do that. It's one of the best ways I help treat my condition in addition to medication," she said.
Flygare also tries to let others know if she's experiencing sleepiness and not able to process or keep up with a conversation. She doesn't want people to think that she's mad or annoyed. Communicating about her symptoms is area where Flygare is trying to improve.
"Usually, when people find out I have narcolepsy, they say, 'Oh, do you know that you're having an episode?' They think they know what it is already, that I'm going to fall asleep in the middle of a sentence or while I'm standing," Flygare said.
It's an inaccurate perception of narcolepsy, one often misportrayed or played for laughs in the media. A character played by Rowan Atkinson fell asleep while running in the film "Rat Race," and one of Deuce Bigalow's dates in "Deuce Bigalow: Male Gigolo" fell asleep while bowling.
Feeling misunderstood is sometimes worse than the symptoms themselves, Flygare said. That's one of the challenges of this invisible illness.
"Cataplexy is pretty visual," Flygare said. "If you see it, it looks somewhat like fainting or like a seizure. It looks very strange, and so people do kind of pick up on that one unless it's really subtle. But it's interesting with the sleepiness of narcolepsy that can be really invisible.
"A culture that respects sleep would be so exciting, one that sees sleep as an important gateway to success."
After signing up for the marathon, Flygare created her own training plan for the 26.2-mile race with an elevation gain of 5,676 feet.
Knowing the constraints of her limited energy and time, she took a minimalist approach to training. If she ever sensed any cataplexy, she skipped training for the day.
"It's so terrifying to feel paralyzed while you're conscious," Flygare said. "I had so much frustration about that, but then I started to realize that every time I wasn't experiencing that body paralysis was really awesome and that just being able to stand and walk and run was such an amazing thing."
During the marathon, Flygare carried an ultralight running pack with water and extra medication in case there was any issue with her cataplexy, at one point dodging an episode by staying calm as she ran past a snake.
On March 4, Flygare proved that sleepiness is not laziness. She finished the marathon in 5 hours and 48 minutes.
After returning home from the challenge, she slept for about two hours -- and felt triumphant and proud.
"The marathon taught me the power of just showing up," Flygare said.