Bush, at 60, showing no signs of slowing

CRAWFORD, Texas, Aug 6 (Reuters) - Just weeks after his 60th birthday, President George W. Bush showed no signs of slowing down on Saturday, powering his mountain bike up steep hills in 100-degree (38 Celsius) heat and exhausting younger riders.

Confident that a U.N. resolution on southern Lebanon was essentially complete, Bush broke away from his ranchhouse yesterday for a spin around his 1,600-acre Texas ranch, across single-track trails that he helped hack out of the dry, dusty environs.

While some of his Democratic critics have complained he spends too much time on his bike, Bush said the exercise helps him deal with the pressures of the presidency.

''Riding helps clear my head, helps me deal with the stresses of the job,'' a sweat-soaked Bush said after an hour-and-20-minute ride that shot his heart rate up to 177 beats per minute at the top of one climb.

The president set a brutal pace for his accompanying riders, who included two Secret Service agents, White House spokesman Tony Snow and this reporter, who managed to gasp his way through the 20-km ride.

''What I would give to be 16 again!'' Bush yelled out at one point as he mashed the pedals of his Trek bicycle through a wooded area.

In fact, Bush does not ride quietly, constantly shouting out in his Texas twang the names of trees and geographic features and yelling at himself to pedal faster.

''Air assault!'' he yelled as he started one of two major climbs, up Calichi Hill, which he named for the white limestone rock from which it is formed.

Bush was in between work sessions at his ranch, having conducted a videoconference with Secretary of State Condoleezza Rice, Vice President Dick Cheney, national security adviser Stephen Hadley and national intelligence director John Negroponte.

After his ride, he was having lunch with Rice and more talks on the Middle East.

NOT 'LEISURELY RIDES' The president, who turned 60 on July 6, was found by doctors at the National Naval Medical Center in Bethesda to be in the superior category of fitness for a man his age, after his annual medical check-up this week.

Standing in the shade of a tree while one of his dogs, Miss Beazley, barked, Bush said he does not try to think out solutions to world problems while riding, instead use the rides to clear his head.

''I push it away. On single track you generally have to stay focused on the trail. And as you know these aren't leisurely rides, these aren't nature rides,'' Bush said. ''They're fun exercise rides, and I try to maximize the time available and at the same time stay fit. In my case I know I need to be spiritually fit as well as physically fit in order to do this job.'' Bush said he spent the previous evening thinking about the Middle East while sitting on the porch of his ranchhouse waiting for first lady Laura Bush to arrive.

''I was thinking about the right strategy for the United States in the Middle East. I spent a long time thinking about it, went in and wrote some notes, I then shared my thoughts this morning with some of my inner circle,'' Bush said.

Bush likes people around while he rides, and indeed in addition to the other riders were several off-road, gas-powered all-terrain vehicles filled with Secret Service agents.

Get behind one of those vehicles, as I once did, and you suck in a mix of prairie dust and gasoline fumes, as well as suffering the indignity of having been dropped behind the group.

Bush keeps his eyes on the road, and one of his rules is that he generally does not want anyone to ride in front of him in order to enjoy at least the sense of solitude.

''The reason why, is that when I'm riding and seeing straight ahead with my I-Pod plugged in, I feel like I'm alone,'' he said.

REUTERS AKJ HS0852