Gary Westlund was a forward-looking 18-year-old when he bought his first book about aging. Now, at 60, he sees this as a little like reading a parenting manual about 40 years before you're facing the screaming toddler.

"It's altogether different when we start experiencing it," he said. These days, Westlund faces "near constant reminders of the discomfiting, painful fact that I'm getting older."

However unwelcome, those "reminders" are symptoms with which Westlund is uniquely positioned to cope. He is the founder, president and owner of Charities Challenge Inc., a nonprofit organization that offers fitness training and hosts a series of annual 5K and indoor track races in St. Paul and Arden Hills, one or more every month. Many of the races are presented as a "challenge" to some health adversity, including obesity, diabetes, depression, addiction, cancer, arthritis -- and, of course, aging.

Westlund, a longtime runner, race walker, trainer and fitness instructor, as well as a certified health fitness specialist with the American College of Sports Medicine, designed the challenge races to encourage people with these limitations to stay active despite them. Much of Westlund's career revolves around the idea that infirmities, far from inhibiting exercise, present all the more reason to do it.

This isn't just the coach talking, it's a conviction based on hard-earned experience. Despite an impressive list of athletic accomplishments -- 37 marathons and ultramarathons, about 700 other road and track races, state and national race-walking championships -- Westlund has experienced some substantial health challenges of his own.

He was diagnosed in his mid-40s with advanced osteoarthritis, a genetic degenerative joint disease that causes increasing pain and difficulty of movement. He has undergone two total hip replacements in the past 10 years. He also suffers from metatarsalgia, a painful inflammation of the foot.

For most of his life Westlund, like many young and healthy people, presumed that he could manage to stay that way indefinitely as long as he kept active. Turned out it wasn't that simple.

"I'll always remember the doctor putting the X-rays up [when diagnosing his osteoarthritis] and saying, 'Well, you've had a nice run, Gary,'" Westlund said. He paused, then added, "I know what it is to be discouraged."

And Westlund sometimes does sound discouraged when he talks about his health, particularly the afflictions of aging. He speaks of turning 60 last winter as a daunting milestone that made him "very much aware of mortality." He likes to quote Ecclesiastes 12, a Bible passage that describes old age in decidedly non-upbeat terms, as a time when "the keepers of the house tremble, and the strong men are bent, and the grinders cease because they are few, and those who look through the windows are dimmed; when the doors to the street are closed," metaphors for the weakening of the body, loss of teeth, dimmed vision, loss of hearing.

"A lot of what goes out of life as we age is pleasure," Westlund said. Not to mention physical comfort, strength, uninterrupted sleep and so on.

Not the cheeriest of horizons.

But is that an excuse to sit around watching TV until the end comes? Not in Westlund's view. For one thing, he likes to describe sitting as "the most dangerous thing you do all day" because of health problems associated with being sedentary, even for those who also exercise. For another, having raced alongside octogenarians, double amputees with prosthetic legs, wheelchair users, people with cancer and heart disease and any number of other diseases and impairments, Westlund doesn't accept excuses.

"The person who finds an excuse is the one who suffers most," he said, because that person will be deprived of exercise's therapeutic effects.

He divides people into "usual agers" -- those who passively succumb to encroaching enfeeblement -- and "successful agers," who strive to stay active, productive and socially engaged. His own life offers evidence that physical fitness, though no shield against ailment, can enhance whatever condition one happens to be in. He points out that when an illness or accident does occur, a person in good shape is better primed for successful treatment and healing. He likes to refer to his exercise programs as RxExercise and says, "if exercise is medicine, there appear to be no side effects."

In a way, Westlund's health challenges have simply forced him to confront a reality that's shared, if not readily acknowledged, by all mortal beings.

"These are very, very precious steps that I take now," he said. "Sort of like sand in an hour glass. Every step takes me closer to that last step I'm going to take."

Katy Read • 612-673-4583