Fighting Cancer With Exercise: One Woman's Story.

April 3, 2000 (Nederland, Colo.) -- Of the hundreds of bike races Karen Hornbostel has entered, the memory of a certain competition in the mountains of Colorado is especially vivid. "The course climbed up and over a high pass," she says. "About the time we started descending -- still 15 miles from the finish line -- a horrible storm swept in and started spitting marble-sized hail at us. I was soaked to the bone and shivering." The only way to escape the storm was to put her head down and keep pumping toward the finish line and shelter.

Hornbostel is tanned and brawny, with a head full of silver curls and a seemingly perpetual smile. Since she was diagnosed with breast cancer seven years ago at the age of 40, she has kept the memory of that race in her mind like a talisman. "That's what fighting cancer is like," she says, "You reach the breaking point, but your only option is to keep going."

The diagnosis launched Hornbostel, a Littleton, Colo., exercise physiologist and top amateur bike racer, onto an emotional roller coaster. Her doctors recommended surgery followed by chemotherapy. "Once I knew what I was dealing with, I geared up," she says. "In 20 years of bike racing I learned what it was like to push my body, to test its limits. I told myself, OK, I can handle this. I won't feel great, but I can get through it."

Hornbostel bolstered her strength during cancer treatments with weight lifting, bicycling, and cross-country skiing. "I didn't pressure myself to keep up a high intensity," she says. "When I felt terrible I'd back off. But those days where I just felt sort of bad were the days when exercise was most important. Once I got out on my bike or my skis, I'd be energized."

Hornbostel tolerated chemotherapy better than most people, and she's certain that exercise was the key. She believes that staying active gave her the stamina to keep working at her job as a health educator at an aerospace company. Her workouts, she says, also helped her cope with anxiety.

Two years after being diagnosed, Hornbostel was back on the racing circuit. She pledged her winnings to a cancer research fund, and other racers followed suit. The following year, Hornbostel beat everyone else in her age group at the U.S. Nationals competition. "I was finally back to my old form," she says. "It felt really good."

But in December of 1997, Hornbostel learned that the disease was back, and this time it had infiltrated her bones. Her best bet was a radical stem-cell transplant, a procedure that would decimate her immune system. To prepare, Hornbostel trained for the race of her life. "I knew I needed to have my body in top shape. I needed to do everything I could to get strong and get my immune system ready," she recalls. She lifted weights, biked, and cross-country skied as much as she could in the time leading up to procedure.