MEMPHIS, Tenn. - On a recent afternoon, Mary Heim pulled into the parking lot at the Humane Society of Memphis & Shelby County and went inside the building.
Wearing a yellow T-shirt with "Dog Walker" printed on the back and holding a braided rope leash, she went through the double doors to the kennels -- and all you-know-what broke loose.
Heim's appearance was a signal to a few dozen of the 160 dogs at the facility that it was playtime. Every dog, it seemed, began barking excitedly.
Oblivious to the riot, Heim carefully opened a kennel door and put the leash around the neck of Enya, a light brown, mixed-breed dog of about 30 pounds. In an instant, Heim and Enya were charging out the back door to the play yards and large open field.
It was going to be a busy, strenuous night for Heim, and that's just how she likes it.
Since she began volunteering as a dog walker about 16 months ago, Heim, 59, has discovered that the vigorous workouts have improved her fitness and her confidence. Having lost 40 pounds since her introduction to dog walking -- and sometimes running -- Heim has branched out to aerobic kickboxing and yoga.
The first few times she volunteered, Heim says, she had little stamina. If she exercised a dog in the big open field, she quickly had to move back to the fenced-in play yard, where the dogs do most of the exercise.
As her fitness improved with each session, Heim says, "It gave me confidence, and I felt better about myself. I can walk almost any dog now."
Alexis Amorose, who took over as executive manager of the facility in May, says she isn't surprised by that side benefit of dog walking.
"I can't imagine how it wouldn't improve your fitness," she says. "The volunteers are here for three to four hours, and that's sustained exercise."
Most of the 150 or so volunteers, Amorose says, walk 10 to 20 dogs in each session. The dogs are taken out for 20 minutes of exercise twice a day, weather permitting.
The dog-walking program began 13 years ago and has many faithful volunteers.
One who has also found fitness in the routine is Tanja Partee, who works as an auditor at a local law firm.
In 2009, she was laid off from her job with a local pharmaceutical company and found out that same week that she has osteoporosis, a bone disease that leads to increase risk of fractures. In a state of depression, Partee, 38, saw her weight balloon from 120 to 175 pounds.
One day, a friend who was laid off from the same company suggested: "Why don't you do something you really like to do?"
Partee says she has always been a "dog person," so she started volunteering at the Humane Society. Now, she says, "it's my passion."
She found that the vigorous, twice-weekly exercise helped her return to her regular weight, and has helped with the osteoporosis.
Most important, Partee says, "I found out what I'm supposed to do in life."
Amorose says that's a familiar refrain among the volunteers.
"It's really touching to see the commitment these walkers have," she says. Most, she adds, walk the same dogs at each visit.
The walkers, Amorose says, never skip a chance to interact with the dogs. "They don't give up a day, because they know their dogs won't have the same opportunity, or some other volunteer will have to take up the slack."
That same commitment, Amorose says, helps the walkers to stick with their fitness activities.
"It's the four-legged equivalent of a running buddy," she says.
At her session, Partee's first charge was her favorite -- a three-legged mixed breed named Butch. They went to the play yard, where Partee threw a cloth toy "bone" for Butch to retrieve.
There's another aspect of the volunteering Partee likes.
"It's good therapy," she says. "No matter what's going on in your life, when you're here you forget everything."
Heim manages analysts in research informatics at St. Jude Children's Research Hospital and has two dogs she adopted from the Humane Society.
She had planned to volunteer at the Humane Society once she retired, but then she found out about the dog-walking program from the society's website. "I decided to stop waiting and to do the things I wanted to do."
Heim says it is easy to become attached to the dogs, and it's somewhat painful when she finds that one of her favorites has been adopted.
"You don't ever get to say goodbye," she says, "but I know they've gone somewhere good."
(Brent Manley writes for The Commercial Appeal in Memphis, Tenn.)
(Distributed by Scripps Howard News Service, http://www.scrippsnews.com)