Bill Bucklew rode his bike into Colorado on Tuesday, watching as the Rocky Mountains grew ever closer, bringing him just over halfway to San Diego from Virginia in his 4,000-mile quest.

Already a feat in itself, Bucklew’s bike ride has an added element of challenge: he and the three other bikers on his trip have Parkinson’s disease.

Bucklew and his two teammates, Li Jiang from China, who was diagnosed when she was 21, and Steve Iseman from Canada, are on Day 38 of their ride across the county, spreading awareness of the disease and raising money through donations for a cure.

Parkinson’s disease is a brain disorder that affects 10 million people worldwide, according to the Parkinson’s Foundation. It can cause tremors, stiffness and other movement-related symptoms, as well as depression, anxiety, apathy, hallucinations and other cognitive symptoms.

There is no cure for the disease, which is not fatal in itself, but causes symptoms that can be, the foundation’s website says. The U.S. Centers for Disease Control and Prevention rates Parkinson’s disease complications as the 14th cause of death in the U.S.

The disease has various treatment options that can help slow or mitigate the onset and symptoms, which include dietary changes and exercise, Bucklew said.

For Bucklew, exercise has been a huge factor in helping slow his disease progression since he was diagnosed with young onset Parkinson’s in 2012 after seven years of misdiagnosis, he said.

Instead of giving in to his diagnosis, Bucklew was determined to embrace the difficulties and to challenge the idea that a diagnosis meant lower quality of life.

Shortly after his diagnosis, Bucklew completed an Ironman, which led to a “cascade” of active feats for him. Since then, he has walked across the United States and Great Britain, completed the longest ski ultramarathon, run 45 marathons, climbed Mt. Kilimanjaro and Mt. Rainier, completed 11 triathlons and is now biking The Long Ride from Virginia to San Diego.

In total, the group’s ride will take 65 days and cover 4,000 miles, with their current route segment taking them up to Georgetown and then on a six-day adventure through the Rockies.

He recalled the first time he saw the Colorado mountains from Kansas, saying that, as they peaked over the horizon, the beauty is “unbelievable.”

They crossed into the state on Tuesday and have loved the views, the people and the beer in Colorado, he said.

The ride hasn’t been easy, Bucklew said, but it’s been worth every moment.

During a section of gravel riding through Illinois, their group had eight flat tires in one day, he said.

Despite the hardships, the ride has “reinvigorated” his belief in the goodness of people, he said.

“We’ve had hotel rooms given to us, lunches and dinners, people just going out of their way to help us,” he said. “The people have just been so awesome.”

Bucklew is riding a tricycle ridden by Davis Phinney, a retired professional road bike racer who was diagnosed with young onset Parkinson’s at age 40. The tricycle allows for cycling even when balance is a challenge, he said.

Phinney had started the Davis Phinney Foundation, based in Boulder, to promote and fund research for the disease.

Donations Buckew’s team receives will be split between the Davis Phinney Foundation and the Michael J. Fox Foundation, which also funds research and awareness.

Riding the tricycle has inspired others with his disease to look at methods of adaptive exercise, Bucklew said. He recalled talking to a man with Parkinson’s who didn’t realize he would still be able to ride a bike due to his mobility, but immediately starting looking into tricycle’s like Bucklew’s.

The community of people helping over the course of the ride is key, Bucklew said. For people with Parkinson’s, having a connection to a community of others with the same disease makes it feel less isolating.

“It’s so amazing to be connected with other people who have (Parkinson’s) because you can share ideas and work through problems when you feel comfortable with each other,” he said. “Some of these people had no connection to the community at all before and now they have a community for life.”

More information about the bikers, their ride and the cause can be found on the website for Bucklew’s nonprofit: UnCorked Adventures.