George Dunn, 55 Meet Mt. Rainier’s undisputed king. Dunn has bagged the 14,410-foot peak 495 times (and counting) on a mountaineering career that has taken him up 5.5 million vertical feet over 600 expeditions on five continents. And he continues to guide mountaineering trips between 50 and 75 days each year. His secrets: loving his job and staying in motion ("If you keep active your entire life, well, no one knows what the boundaries are," he says). Dunn stays trail-fit and prevents exercise boredom by mixing up his workouts. "Variation helps optimize training across the lifespan," says Kent Adams, director of the Human Performance Lab at California State University-Monterey Bay. Changes in training activate different muscles and decrease joint stress. Mix it up as much as possible with road and mountain biking, which naturally lend themselves to interval workouts. And simple changes to strength training (more weight/fewer reps; switching weight implements) will benefit overall muscle tone and fitness if done once every two or three weeks.
Photo by Jimmy Dunn
Fitness Special—Hike Forever: Age 50-65Fight the sedentary lifestyle and get a move on with these exercised and essential skill.s