CONYERS, Ga. – Randy Martin’s workouts are literally an uphill battle.

Three times a week, he and his exercise partners climb stairs at a fitness studio in this Atlanta suburb. He has lost 31 pounds in seven months on the exercise routine, and a plaque commemorates his going up and down “The Original Stairmaster” 100 times without stopping.

“It builds a lot of strength in your legs, and stamina,” said Martin, a 37-year-old businessman. “And my girlfriend notices.”

On Saturday, Martin will put his workouts to the test when he, and more than 200 others, scamper up 1,378 stairs of one of the tallest buildings in the Southeast in a fundraiser style becoming increasingly popular. Organizers hope the climb up the 55-story Bentley Forbes Bank of America Plaza building will become an annual event.

“It does a little bit of everything; it’s great cardio, it builds muscle endurance and strengthens your muscle,” said Penny Arthur, owner of the Shut Up and Squat studio where Martin works out. “But the stairs, they don’t get easier as you do them, either.”

Similar skyscraper stair climbs have popped up in Chicago, Boston, Denver, Detroit, Toronto, Miami and San Francisco. But New York claims the granddaddy of them all, the Empire State Building Run-Up, which has been held every February since 1978 by the New York Road Runners.

“It is a most wacky race. You’re running straight up 80-odd floors, in a stairwell. It’s like extreme running,” said Richard Finn, spokesman for the New York organization.

Donna Brazzell, coordinator for the Atlanta stair climb, said the American Lung Association hosts stair climbing fundraisers in part because it is a cardio-lung workout that in 15 minutes can provide the same benefits that come after running twice as long on level ground.

“It’s kind of a unique sporting event. Cyclists, health and fitness people are interested in it,” Brazzell said. “It’s not only for very, very fit people but people that want to (exercise) in a challenging way.”

Some enthusiasts travel from event to event. Eric Leninger, 23, of Geneva, Ill., won a trip to the April 14 Lining Up the Wachovia stair climb (1,210 stairs) in Miami after he won the 680-step Tackle the Tower run in February in the Chicago suburb of Oak Brook. Leninger also plans to run in the Climb Atlanta event.

“I ran cross country in high school and track, but I really enjoy this more,” he said. “It takes a certain kind of mental attitude to do it. Anyone can walk up stairs but to really run up it, mentally you have to really want to do it. People don’t really understand how tough it is.”

Because stair climbing demands a lot of aerobic capacity, it’s not for everyone, said Nicholas Rummo, director of cardiopulmonary services for Northern Westchester Hospital in Mount Kisco, N.Y.

“You wouldn’t want people to start an exercise program with stair climbing with vigor without medical advice,” Rummo said.

Even fit people shouldn’t be climbing stairs for a workout everyday, said Joseph Chevalier Jr. of the Morehouse School of Medicine’s health and wellness initiative.

“It’s such an intense workout, you will wear yourself out. It’s important to not try to do very much,” said Chevalier, who is helping train a team from the school for the Atlanta climb.