BEND, Ore. – In the cool of a red-sun morning, Johanna Olson effortlessly ran through Farewell Bend Park, legs floating as if unshackled from gravity.

Out here is where Olson, 33, feels her best. Here it’s just the rhythm of her breath, her mind unburdened by what’s happening in her head.

“It sounds so cheesy,” she said, “but running is the one thing in my life that’s always there and always good.”

A tenacious tumor lurks inside Olson’s brain, a shadow that has stalked her since she was 18 years old.

It first made itself known when Olson was in her first season as a star cross country runner at Luther College in Decorah, Iowa. Over the course of two years, she had a brain surgery and a round of radiation treatments.

Her good health returned, Olson quickly racked up cross country accolades such as league most-valuable player, seven-time All-American and, finally in 2000, NCAA Division III women’s individual cross country champion. After college, she twice competed in the U.S. Olympic trials.

But in 2009, after more than a decade of quiet, Olson’s annual CT scan showed the tumor had returned.

Since then it’s been a journey of treatments and surgery and doctors. She regularly feels tired, her once muscular body now so thin. She will find out this month if the latest treatment – a drug meant to arrest the tumor’s growth – is working, and what comes next.

Not that all of this is Olson’s focus. She ran the Medtronic Twin Cities Marathon on Sunday in Minnesota.

The downturn in her health came on fast.

One day she started seeing spots. She couldn’t see well enough in class to take notes later that same day. Then came headaches.

She went to a hospital. After a CT scan, doctors advised her to go quickly to the Mayo Clinic in Rochester, Minn. Specialists operated on the tumor by the end of the week.

Even today, doctors don’t know why she has it, and say it had probably been slowly growing for years before the day she began seeing spots.

They also told her the tumor would someday come back.

Brain tumors always return, said Dr. Stephen Kornfeld, Olson’s attending physician at St. Charles Cancer Center in Bend.

“It can be – and in Johanna’s case it has been – managed like a chronic illness,” he said. “But ultimately, brain tumors are incurable.”

After graduation, Olson headed west. She wanted to train at a higher elevation for the 2004 Olympic trials and fell for the beauty and charm of Ketchum, Idaho.

Olson qualified for and competed in the 2004 and 2008 Olympic marathon trials. She didn’t make the team but still was considered among the best distance runners out there. Even today, Olson is sponsored by Brooks, the running shoe and gear brand.

In that decade of respite from cancer, Olson regularly moved, from Ketchum to Spokane, Wash., and then to Corvallis, Ore., to earn a master’s degree in exercise and sports science.

She returned once a year to the Mayo Clinic for a CT scan. It was the only time of year she got anxious. For years, it was clean.

Then in 2009, the scan showed what doctors had said: The tumor was back.

It prompted a second surgery, plus time recuperating in Minnesota. The surgery also showed that the tumor was now more virulent.

“I hoped I would have at least another five years,” Olson said. “I hoped that it would be gone again for a while.”

With that mindset, she left home for Bend in 2010 to take a job at the Exercise Physiology Lab at Central Oregon Community College. She immediately worked to connect with local runners.

Bend resident Kari Strang said one of the first days they spent much time together was at the Peterson Ridge Rumble, an annual trail race outside Sisters, Ore.

The news has been tough in the past year. Six months into chemotherapy, Olson’s white blood cell and platelet counts dropped to the point that doctors said she had to give her body a break.

In August, Olson learned that within two months of stopping the chemo, the tumor doubled in size.

Olson has started another treatment since. It isn’t chemotherapy. Rather, it’s a drug geared toward keeping blood vessels from feeding the tumor. She will learn in several weeks if it’s working.

Since the tumor growth, Olson has noticed changes. Nothing that a new acquaintance would notice: A slight pause here, a forgotten phone number there. But a regular conversation can now take a lot of energy. She forgets a word and then searches in her mind for a way around it.

Throughout it all, Dr. Kornfeld said he has admired Olson’s optimism and resilience. It’s so important, he noted, for patients not to let fear poison their daily lives.

“She’s such a cool kid,” he said. “She certainly embodies that idea to live in the present.”