Hikers set off on extreme treks for all kinds of reasons - everything from building endurance to seeking solitude or reaching remote sites in the wild.
Tim Bowden will tackle a supertough trail Saturday motivated by something else: Parkinson's disease.
Bowden, 67, who was diagnosed with the degenerative disease in March 2007, plans a grueling 15-mile hike from Catalina State Park to the pine-topped heights of the Catalina Mountains.
There's a point to the long, hard plod.
Bowden's hike, with a punishing elevation gain of 5,000 vertical feet, is aimed at showing the power of intense exercise in dealing with Parkinson's - and also raising money to help others with the disease.
Bowden says rigorous exercise at the Parkinson Wellness Recovery Gym in Tucson mitigates the severe stability and balance problems caused by the disease.
"It takes dedication - a willingness to devote a lot of time and effort," says Bowden, crediting neuroscientist and gym founder Becky Farley for critical guidance. "But I feel better when I do the exercises, and the symptoms of Parkinson's are much less."
Here's evidence that something very positive is going on: Bowden's trek Saturday - with his wife, Diane, and a few friends - will be his third trip up the 15-mile route in as many years.
Contributions in support of his trek will go to the gym to benefit other Parkinson's patients.
Bowden, a professor emeritus in cellular and molecular medicine at the University of Arizona, was diagnosed with Parkinson's after he began showing symptoms including a disturbed gait and movement problems.
"It was a devastating diagnosis," he says. "My major deficit was on my right side. My right arm did not swing when I walked, and I did not lift my right leg as high as my left leg. I also had problems with my balance."
Having a severe disease with no known cure is a blow to anyone. For Bowden, a lifelong athlete and outdoor adventurer, it seemed that Parkinson's would deprive him of the activities he so loved.
"Diane and I started hiking, backpacking and rock climbing in about 1967," a year after the two - who grew up in Cincinnati - were married, Bowden says. "We started running in 1974 - doing marathons and half-marathons. We cross-country skied, sea kayaked, fly fished and climbed mountains."
Most of those activities slipped out of the Bowden lifestyle when he was struck with the severe balance and movement problems brought on by the disease.
"We thought our lives would have to become much more sedentary," says Diane Bowden.
Medications offered promise.
"Soon after diagnosis, I started to take Parkinson's disease medications" - including Levodopa, Bowden says.
The drug helps, but it has limitations.
"Parkinson's is a degenerative disease in which cells in the brain start dying and you start running out of dopamine - and your brain can't tell your muscles what to do," Bowden explains.
Levodopa, in a somewhat complex process, is converted to dopamine and improves the brain-muscle connection.
"It's effective but unfortunately, with time, you have to start taking more of the drug," which can bring on unwanted side effects, Bowden says.
The troubling bottom line: "The medications helped with some of the symptoms," Bowden says, "but I could not pursue many of these strenuous activities."
He needed some other kind of medicine.
That medicine turned out to be something already familiar to Bowden: intense physical exercise.
He turned for help to neuroscientist Farley and the exercise program she was developing for Parkinson's patients.
INTO THE GYM
Bowden lauds Farley's work for "creating an exercise model" that helps people with Parkinson's to "slow their symptoms and improve the quality of their lives."
He has been a regular in the nonprofit Wellness Recovery Gym, at 134 W. Fort Lowell Road, since it opened in 2010. He also works out with a personal trainer and takes daily walks.
Farley, who says about 80 Parkinson's patients take part in group exercises at the gym, set very high goals.
"What makes the gym unique is that we're really trying to implement exercise as medicine," she says.
"In the past, the goal for a person with neurodegenerative disease was just to make their life comfortable," Farley says. "But a lot of compelling data show that exercise may slow the disease progression."
Her specialty exercises for Parkinson's patients emphasize big and fast movements.
"The primary symptoms of the disease are slow, small movements - so we work on acceleration and big movements," she says. "On top of that, you want to build complexity where the brain gets engaged. So it's not to just lift a weight with a single joint, but also to go through obstacles and use your mind to solve problems as you move. It might be reciting something out loud or doing a simple math problem as you're doing the exercises."
Farley maintains that the techniques work - and that Bowden and others are the moving, improving proof.
"Tim is an extreme example of where you can take this, but everybody has the ability to do something they have never done before," she says.
ONTO THE TRAIL
Hikers familiar with the rugged canyons and steep ridges of the Catalina Mountains will appreciate the challenge Bowden has set for himself. "It's going to be pretty strenuous - especially with the 5,000-foot elevation gain," he says.
The Bowdens and about a dozen others plan to set out at 6 a.m. Saturday and be on the trail for eight hours or longer.
The group will start at the main trailhead at Catalina State Park north of Tucson and follow the Romero Canyon Trail steeply uphill to Romero Pass. They'll finish the hike south of the Mount Lemmon village of Summerhaven.
Will Bowden make it?
"I set a goal," he says. "I'll try my best to reach it but will not do damage to myself."
In the end, the Bowdens say, it comes down to attitude and gratitude.
"Tim has such a positive attitude about dealing with Parkinson's," Diane says. "That makes all the difference."
Bowden reflects, "I couldn't do this without Diane. "Her moral support means so much."
how to contribute
• Tim Bowden's planned 15-mile hike on Saturday is not only a personal challenge, but also a fundraising event for the nonprofit Parkinson Wellness Recovery Gym.
• Go online to www.pwr4life.org and click on the PWR! Hike 2013 button to make a contribution.
"Tim has such a positive attitude about dealing with Parkinson's. That makes all the difference."
Diane Bowden, Tim's wife
Contact reporter Doug Kreutz at email@example.com or at 573-4192. On Twitter: @DouglasKreutz