Diane says running in the mountains gives her a feeling of security
In 1997, Diane Van Deren decided to have brain surgery in a bid to stop the epileptic seizures that were dominating her life.
Twelve years on, Diane, from Sedalia in the US state of Colorado, is a champion long-distance runner - an ultra-runner - and free from seizures.
In February, she was the first woman to complete 430 miles (690km) on the Yukon Arctic Ultra.
The race is known as the coldest, most difficult and extreme race in the world.
She pulled a sled with over 20kgs of food, clothing and equipment and slept just two or three hours a night.
Given her medical history, her achievement was even more staggering.
At the age of 16 months, Diane had a very high fever and was taken to hospital, where she was packed in ice for three days in an attempt to reduce the fever.
During that time she had a seizure that lasted more than 50 minutes.
She was released from hospital days later, seemingly recovered.
However, 24 years later Diane began to have regular seizures and was diagnosed with epilepsy.
The seizures grew worse and over time she felt her role as a mother was suffering.
"It got to the point where my children were starting to care for me and worrying about me," she told the BBC World Service.
"Every time I took a bath I would have to tell my kids or husband to come check on me, because people do die of seizures in bathtubs," she says.
Diane even had to teach her children how to drive, so that if she did have a seizure they would know how to turn the car off and how to get help.
Diane trains four to eight hours a day
Diane would always have a premonition before the onset of a seizure.
"Before my seizures I would get this tingling sensation in my body, and the feeling of this rising in my stomach," she says.
"Basically what happens when a seizure occurs, your brain is just fried.
"And when I had come out of the seizure then I'd have this horrendous headache and my body would be aching and sometimes I actually had blood coming out of the side of my mouth from biting on my tongue.
"Sometimes it would take hours to recover from a seizure and sometimes even days."
Diane eventually developed a way to cope.
Whenever she felt a seizure coming on she would run to the front door, put on her shoes and go running in the nearby Pike National Forest.
She would run for hours and never had a seizure while running.
But after 10 years of seizures which medication failed to control, she began to consider brain surgery.
"I was really at more of a risk of dying from a seizure at this point than from the surgery itself."
Tests found that the area of the brain the seizures were stemming from was her right temporal lobe, so she underwent a procedure known as a right temporal lobectomy.
Doctors first sawed the side of her head open and placed electrodes on to her brain to induce a seizure, to make sure they had found the right area. They then removed the damaged tissue.
Diane has not had a seizure since the operation and is now running races of 100 miles (160 km) or more, running all day and all night without sleep.
"Having the side of my head sawn open was excruciatingly painful," she says, "but then when I'm out on the trail I can reflect on that pain... and the pain that maybe I'm feeling on the trail. It's nothing compared to what I've been through."
Diane does have to deal with the effects of the surgery: short-term memory loss, problems with organisational skills, time management, and visual cues.
For example, when running she can forget which direction she came from.
She trains four to eight hours a day and will typically run 20-25 miles (32-40km) a day.
"She is more like a fine-tuned machine than just an athlete," says her doctor, Barb Page.
"Her brain surgery and the effect that it's had on her has allowed her to excel to a point few people in the world could excel. I think Diane is an exception to practically every rule you could look at."
Her next big plan is to attempt a speed record, racing 20 miles (32km) from the base of Mount Anconcagua, the largest mountain in the Americas.
She says: "My life for 10 years was full of 'what ifs'. Now it's not the 'what ifs', it's the 'I cans'."