ESTES PARK, Colo. . On the first day of the new year, as on the last day of the old year, I slip outside at dusk and try to run away from my problems. There is no better way to make sense of the daily clutter of inchoate thoughts than bouncing along a trail, immortality in every stride.

Of course, everything hurts . joints, calf muscles, a toe that refuses to warm. When someone with more spring to the step passes by, I feel a pang of loss: I’ll never be that fast again. And then, loathing at having that thought. It’s a bad day when the most creative thing you do is come up with an unoriginal form of self-pity.

It helps to have smarter people musing on the same subject. “There is no escaping the tragedy of life, which is that we are all aging from the day we are born.” So writes Atul Gawande, surgeon, author and courier of common sense, in his book “Being Mortal.” He goes on to show that the real tragedy is not every click of the postpartum clock, but how we have come see aging as a disease.

I came to Dr. Gawande’s book after meeting a most remarkable man in this alpine town set against the overly ambitious geology of Rocky Mountain National Park . Tom Hornbein. He’s also a doctor, elfin and energetic, bearded and balding, who will defy gravity on many a day by clipping himself into a climber’s bolt on a vertical flank of said Rocky Mountains. He’s 84.

Climbers know Dr. Hornbein for his historic accomplishment in 1963: ascending the West Ridge of Mount Everest, with Willi Unsoeld, and surviving a night at 28,000 feet without tent or sleeping bag. If not the most extraordinary achievement in mountaineering, it is very high on the all-time list. “The night was overpoweringly empty,” he wrote. “Mostly there was nothing. We hung suspended in a timeless void.”

He got lucky, as there was no jet stream wind on that night. But luck, as they say, is the residue of design, and Tom Hornbein is nothing if not methodical. His book, “Everest: The West Ridge,” is widely recognized as a classic. It’s aging well, in part, because so many contemporary books on mountain climbing are all about score settling and product placement.

I was whining, in as diplomatic a way as possible, about reaching an age when the high summits no longer have quite the pull they did for me, when a beer and a brat on the 40-yard line can be just as enticing as looking down at cloud cover from Mount Rainier’s apex. After listening to Hornbein describe a routine that includes regular rock climbing with Jon Krakauer, another Colorado author and mountaineer, I asked him about his secret to aging.

It may be true, as George Orwell said, that “at 50, everyone has the face he deserves.” Orwell died at 46, so his observation was purely speculative. But what about the body we deserve? Hornbein clearly takes care of his, though he doesn’t make any of the annoying claims of the aging-well proselytizer.

He said he experienced very little physical loss in his 50s and 60s. In his 70s, body parts started to creak and pop, and he noticed gradual decline with every year. In his 80s, he’s slower, much more cautious, and cognizant of his limitations. The will is there, if not always the way. But he shows up, proof again of the adage about success.

During a recent warm weather spell, “I got out with a young friend to do some bolt-clipping sport route he’d prepared for me to lead,” he said. “Not difficult, but quite enough.”

Hornbein brought up Gawande’s book. He laughed at himself, noting that he was at an age when death is a regular topic of conversation. Hornbein goes to a lot of funerals. Friends, including some who touched the roof of the world, are dead or dying. He said all of this with a twinkle in his eye. Or at least it seemed that way to me.

Gawande makes the point that we’ve got to get over the idea that aging is a disease. “People live longer and better than any time in history,” Gawande writes. “But scientific advances have turned the process of aging and dying into medical experiences.” And he concludes, “Death of course is not failure. Death is normal."

Keeping normal at a safe distance, however, requires some deliberation and some risk-taking . both in moderation. The mountaineers who made history a half-century ago, and are alive today, like to cite this admonition: There are old climbers, and bold climbers, but no old, bold climbers.

Hornbein is too modest to add a coda. There may come a time, not so long from now, when the steps to his front porch will seem like Everest. But listening to him talk about plans for the coming days, in and out of the mountains, I drew one conclusion. He stays in motion, whether going up, down or sideways.