Body of Work

Body of Work

For a Bethesda fitness instructor, exercise is routine

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It’s the last few minutes of a grueling, hourlong cycling class, and everyone is breathless and exhausted—except Kirsten Molloy.  

The 51-year-old Bethesda resident, with off-the-charts energy and the physique of a much younger woman, grins and performs a peppy little shimmy dance on her bike.

Molloy, a fitness instructor and triathlete, attributes her seemingly endless stamina to routine exercise, which she began to embrace seriously 18 years ago. “It keeps me young,” she says.  

Back then, Molloy became enamored with yoga after trying a class to help improve her posture. A year later she was running the class herself, and soon after began teaching a range of fitness classes, refining her workouts and competing in triathlons.

These days, Molloy’s second home is the gym. Each week she shuttles between Bethesda’s Washington Sports Club and Rockville’s Life Time Fitness to lead two yoga classes, four cycling classes and a strength-training class. As part of Life Time’s triathlon training program, she helps lead three 90-minute sessions weekly that include running, biking, swimming and strengthening exercises.  

She also runs three to four miles each week and does 90 minutes of weight training and exercises with a trainer. She competes in as many as five triathlons annually, events that generally include one-mile swims, 26-mile bike rides and 10K runs.

Molloy says she maintains her youthful endurance by exercising smart, focusing on heart rate-based training, building core strength and eating well. She’s healthy, looks great, feels great and has medaled in three triathlons in the past two years.

What she does:

Follows her heart

When doing cardio exercises, Molloy keeps her heart rate in specific ranges or zones, tracking it with a Polar heart rate monitor programmed by her trainer.

Molloy mostly exercises in the lower intensity zones, moving from being able to easily speak to having some difficulty as her intensity increases. She pushes into the higher zones, where it’s difficult to say even a sentence, usually in 75- to 90-second bursts during a cycling class.

In a triathlon, Molloy pushes a little more than she does in a typical workout, but still mostly sticks to lower intensity zones. “Slow and steady wins the race,” she says.

The Payoff

Training in the lower zones builds Molloy’s aerobic base and endurance, plus it increases her body’s ability to burn calories using less effort.

“It’s counterintuitive,” she says, “but if you train mostly in high zones, you lose your aerobic base, and your body does not become efficient at burning calories.”  

People who train that way often wonder why they flame out at races or can’t seem to lose weight, she says.

Despite “eating like a horse,” the 5-foot-8-inch Molloy weighs a slim 130 pounds, the same as her weight at age 18. Cardio evaluations show her overall fitness has improved—with indicators impressive even for a woman in her 20s. The small spurts of high-intensity training help build Molloy’s cycling speed, which has increased from 16 to 21 mph.

Works the core

During yoga and strengthening work, Molloy focuses on her body’s “core,” including abs, glutes and back.

The Payoff

“A strong core keeps you safe,” says Molloy, who has avoided injury since intensifying her core training. Without a strong core, it’s possible to lose form, use the wrong muscles and become fatigued faster and open to injury.

Keeps fuel in the tank

Molloy eats an hour before a workout or race, often oatmeal with berries for carbs, and nuts for protein.

Within 45 minutes after a workout, she consumes protein, such as eggs.

She drinks at least two bottles of water before exercise and takes a minimum of three sips every 20 minutes while training. No sports drinks allowed. “Too high-calorie,” she says.

The Payoff

“You have to eat and drink so you can perform. Otherwise you’ll run out of gas,” she says. Consuming protein after a workout helps rebuild muscle, so “the next day you won’t feel beat up.”

Leah Ariniello is a Bethesda-based writer who frequently writes about health.

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