Can't find time to run 5 miles every day, only take a neighborhood walk?

Too busy with kids and work to get to Ala Moana for a heart-pumping swim, and have to settle for a few brief laps in the local pool while you and your mate take turns shepherding the kids?

Breathe easy.

A study at Duke University has found that low-intensity exercise "dramatically lowered" triglyceride levels. Triglycerides are those pesky particles that lug fat around the body. Reducing their numbers can reduce the risk of both heart disease and diabetes.

The Duke study joins a growing body of evidence suggesting that you don't have to ride 2,200 miles around France to enjoy good health. Regular jaunts through the neighborhood will do just fine.

One group that may be especially glad to hear that exercising in moderation is good: parents. More specifically, parents who were quite active before they had kids. Because another recent study, this one released in May by the University of Pittsburgh, found that having kids sidelines a lot of active couples.

TRIGLYCERIDE LEVELS IMPROVE

The Duke study involved 240 middle-age, sedentary types who were divided into four groups and studied over eight months. Three groups exercised, doing time on the treadmill, elliptical trainer and stationary bike. One group exercised a lot and did so with great intensity, one group also exercised with great intensity but not as much, and the third group exercised in moderation. A fourth group, the control group, retained its sedentary ways.

To the researchers' surprise, it was the modest exercisers who showed the most change in terms of triglyceride levels.

The study — part of an ongoing fitness and activity study at Duke called Studies of a Targeted Risk Reduction Intervention Through Defined Exercise — also found that the positive effects of exercise lasted longer for the modest exercisers than for the more intense exercisers.

Improved levels of high-density lipoprotein particles, or HDLs, persisted more than two weeks after the moderate exercisers quit exercising modestly. That's good because HDLs escort cholesterol through the bloodstream to the liver, where it can be eliminated from the body.

"More is generally better than less when it comes to exercise," cautions Cris Slentz, an exercise physiologist at Duke and lead author of the study. But, he adds, these findings are certainly an endorsement for moderate levels of exercise.

OTHER STUDIES BACK MODERATION

They join a host of studies with a similar message. Among them:

• A six-month study published in the Journal of the American Medical Association showed that women who work out as little as 72 minutes a week improved their fitness level by 4 percent.

• A 2006 study by the U.S. National Institute on Aging found that of 302 older people studied, death rates went down as activity levels — including activities as tame as vacuuming and running errands — rose.

• The 2001 Iowa Women's Health Study of 40,417 women between ages 55 and 69 found that women who engaged in moderate exercise — including bowling, golf, gardening and long walks — reduced their chances of dying by 37 percent. There was no such reduction observed for women who jogged, played tennis, swam or did aerobics.

"Younger Next Year: A Guide to Living Like 50 Until You're 80 and Beyond," by retired lawyer Chris Crowley and Dr. Henry S. Lodge, has a theory about why this is, says Raleigh, N.C., bike shop owner Kevin Coggins, a disciple of the book that came out in 2004.

"What's the human body been doing the last 3,000 years?" asks Coggins. "It wasn't doing hard-core endurance athletics. It's been walking with short bursts of speed, quick bursts to capture prey, then walk back home.

"That's what's in the DNA of the human body — all-day low-intensity exercise."

PARENTING CUTS EXERCISE TIME

The Pittsburgh study found that parenthood can wreak havoc with exercise regimens. Women who worked out four hours a week suddenly found themselves down to 90 minutes after having a baby. Fathers in the study typically went from just under eight hours of exercise a week to 4 1/2.

No need for that, say Mike and Alisa Wright Colopy, veterans of the active-couple-turned-parents scene.

In the early 1980s, the Colopys were the epitome of the active couple. Mike did swimathons and cycled, Alisa was getting into triathlons.

Even when Alisa became pregnant with their first son, Travis, that didn't slow her: On the day he was born in 1986, she managed to run six miles and swim one before heading to the hospital.

As soon as Travis was home from the hospital and could keep his head up, he was out on training runs with mom and dad in one of the first generation baby joggers. When brother Glen came along two years later, they bought a two-seater.

"We'd go out three or four times a week, maybe three to six miles," says Mike.

The true transition to more moderate exercise came when the boys were ready to strike out on their own.

"When the lads were 4 and 5 years old and I was pushing more than half of my body weight, we had to become more creative in our exercise plan," says Alisa, who runs Fit and Able Productions, a Cary-based nonprofit that aims to get families active.

That meant some tag-team exercise: one parent playing with the kids in the main pool while the other swam laps, then swapping, for instance. But it also meant finding exercise wherever they could.

"We went to the zoo all the time," says Mike. "A zoo is acres and acres of land; you're constantly walking. You're not cognizant of it because you're always looking at stuff."

WORKING OUT WHERE THEY CAN

Parks and museums were other places where the Colopys would work in some exercise.

And when the kids got into organized sports, Mike and Alisa didn't sit on the sidelines gabbing with other parents.

They brought their running shoes and shorts and worked in a run.

Thus, the Colopys were able to weather parenthood on a more moderate exercise schedule, one that could be adopted and adapted by the child-free and, as the Duke study is the latest to show, used to optimal benefit.

What you don't want, says Duke's Slentz, is to become like the study's control group, which did nothing other than gain two pounds, on average, and grow a half inch around the waist.

"That may not sound like much," says Slentz, "but over a decade at that rate that would mean an additional 40 pounds and 10 inches."

Forty pounds and 10 inches that even a moderate exercise regimen could keep away.

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