“I’ve been doing it since before I retired,” said Rich White, a former accountant who lives in Alexandria. “It’s easier to get up and get it out of the way so I don’t miss it. Both of my parents died prematurely of heart attacks. That’s when I decided to start running to get in shape. Eventually that turned into a habit of daily strength and aerobic exercise.”

White’s assumptions about preserving his physical health are underscored by a report from the Center for the Study of Aging and Human Development at Duke University School of Medicine which found that physical decline begins when people are in their 50s, much earlier than people might notice or expect.

The study looked at 775 adults ranging in age from 30 to 90 to assess changes in fitness abilities like endurance, balance, speed and strength. Researchers found that exercise efforts must begin before the age of 50 in order to help halt the decline and maintain mobility and independence longer in life.

“Our research reinforces a life-span approach to maintaining physical ability — don’t wait until you are 80 years old and cannot get out of a chair,” said lead author Katherine S. Hall, Ph.D. in releasing the study.

By having participants stand on one leg for 60 seconds to measure balance and sit and rise from a chair for 30 seconds to measure lower body strength, researchers were able to detect a decline beginning in one’s 50s. The findings show the need to understand and preserve muscle strength.

“Most tissues in the body respond to stress placed on them by becoming stronger or adapting to handle the stimulus you place on them,” said Joel Martin, Ph.D., assistant professor of Kinesiology at George Mason University. “If you lift weights, your muscles get bigger and stronger. If you don't do any sort of physical activity to stimulate your muscles, then they get smaller and become weaker. Use it or lose it.”

Emma Warner, 72, meets her trainer at a Montgomery County Recreation Center gym twice a week. Together they perform a combination of exercises aimed at improving her strength, balance, endurance and flexibility.

“We stretch and do yoga poses, sometimes we speed walk outside and I also do exercises with two or three pound dumbbells,” she said. “But my mother is 98 and is in pretty good health, so I figure I have good genes. I just need to work on fitness to maintain.”

As people age, change and decline is inevitable, but the rate and severity can vary based on genetics and the level of activity in one’s lifestyle. Regular exercise can have a profound effect on the way in which one ages.

“People have their actual age, which they can't do anything about, and their biological age,” said Martin. “Someone could be 40 years old, live a very inactive lifestyle and not eat very well, which may cause them to be closer to 60 in terms of their biological age. And vice versa, someone who is 60 could be very active and eat a healthy diet and feel like they are much younger, perhaps a biological age closer to mid-40s.”

Fitness instructor Amy Traum has clients who run the age gamut from college students to retirees, but her overarching advice to getting in shape is similar. “Everyone needs a well-rounded exercise program that includes stretching, balance exercises, strength and cardio,” she said. “I always begin and end classes with stretching and I try to add strength and balance elements like a weighted deadlift.”

Those new or newly returning to exercise should start slowly and gradually, says Traum. “It sounds like common sense, but I can’t tell you the number of people who come to my classes with no experience and try to work way above their fitness level and either get injured or discouraged,” she said. “There’s nothing wrong with starting out slow, sticking with it and making gradual progress. Also make it fun, like walk or jog with a friends or take a dance or Zumba classes.”

“Eating a healthy and nutritious diet is also important,” added Martin. “The antioxidants in foods, especially fruits and vegetables, can help to preserve and protect tissues from damage that occurs as part of the natural aging process.”