Somewhere between the bone-jarring descent down a crumbling limestone slope and the white-knuckle slide through creekside muck, I got the feeling that my bicycle ride with President George W. Bush wasn't going to be just another photo op.

Bush grinds his mountain bike across his hardscrabble ranch in Crawford, Texas, the way Teddy Roosevelt led his Rough Riders up San Juan Hill. As bike riding goes, it was more rawhide than Lycra.

"We ride pretty hard," Bush warned a group of journalists as we set out one hot August morning for a 17-mile tour de ranch. "And the reason why is, I like to stay fit."

For decades Bush ran to keep in shape, maintaining a seven-minute mile into his mid-50s. But even the most powerful man in the world, it turns out, is subject to the ravages of time. Two years ago, doctors told Bush his running days were through.

"Like a lot of baby boomers, my knees gave out," explained Bush, who reluctantly traded in his running shoes for a mountain bike. "I believe that mountain biking is going to be an outlet for a lot of people my age," he said. "People are going to realize you get as much aerobic exercise—if not more—on the mountain bike, without being hobbled."

Hobbled is hardly the word that comes to mind. At 59, he ranks in the top 99th percentile for fitness among men his age. He's nearly 6 feet tall and weighs 192 pounds. His at-rest heart rate is an athletic 47 beats per minute.

Bush wears a heart monitor when he rides, and over our two-hour trek his heart rate averaged a steady 139 beats per minute, peaking at a pounding 177 on one extended climb. After burning 1,493 calories, he earned a trip to the chow wagon and joked after the ride that he'd treat himself to an ice cream sundae.

In fact, though, Bush has lost eight pounds over the past year, the result of a combination of exercise and diet, dropping his body fat by nearly 3 percentage points to a lean 15.8 percent.

"When you get into an exercise routine, your habits begin to change. Your eating habits change, your sleeping habits change, your coffee habits change, your cigarette habits change," said Bush, who rides, lifts weights or works out on an elliptical machine six times a week. "Exercise for me has been good preventive medicine."

The president is the first to add, however, that biking has its risks. He took a well-publicized slide on wet pavement into a Scottish bobby at the G8 leaders summit in Gleneagles, Scotland, this summer. He's also flipped over the handlebars and come down on his head.

Bush offers this White House counsel: "I would strongly urge people to wear helmets on mountain bikes."

Bush also wears a mouth guard—it's thin, formed to fit and barely noticeable—and drinks water from a backpack container to stay hydrated while he rides. And he recommends that anyone interested in getting started on a mountain bike take it one slight grade at a time.

"My advice is to start slow and work into it," Bush said. "You know, ride 30 minutes every other day and get used to it and get your legs in shape—and then just step it up."

Bob Deans is a national correspondent and former White House correspondent for Cox Newspapers.

Additional Related Links

Where There's A Wheel (July 2005)

Happy Trails: Flat Paths For Biking (AARP The Magazine Online)

Ride Your Way to Fitness (AARP.org)