Go slow with new workout regimen.

• Position: YOUR LIFE - Brief article

Nature beckons, but be wary with your summer workouts, cautions kinesiology professor C. Buz Swanik of Temple University, Philadelphia. "Anytime you change the mode of exercise you're used to, you're increasing your workload," Swanik says. "If you took the best cyclist in the world and put him on a treadmill, it'd be a lot harder."

Although the lure of working out al fresco stirs many couch potatoes to action, Swanik warns that newbie runners should be mindful of several potential pitfalls when devising an exercise plan. "A person who's been sedentary must be careful of the added stress to their bodies. It's just like the stories of heart attack...