Each spring, they dominate the glossy magazines: beautiful people bounding through gorgeous landscapes. They race through lupine-lush meadows, spring past red rock arches and do more cardiovascular cavorting on pristine beaches than sand fleas.
They look like Lisa Richardson, on vacation in Puerto Vallarta.
"You run pretty much along the ocean, and it is beautiful," says Ms. Richardson, trainer and dietitian at the Body Firm, a personal fitness training studio in Los Gatos, Calif. "It's also pretty hot and sweaty and horrible. People are looking at you like you're insane."
Ah, the realities of trying to stick to your workout routine while you're on vacation. How can you jog when you're staying in a campground with no shower? Where do you work out in Casper, Wyo.? And if Dad won't stop the car to let you go to the bathroom, how can you expect him to pull over for a step aerobics class?
"You do have to be flexible," says Joyce Hanna, coordinator of the health improvement program at Stanford University. "But if you do keep up something, then you're not going to have a big drop in your fitness level when you get home."
How big of a drop? For most people, taking a week off from workouts isn't going to make much difference. Some trainers even encourage it, saying the body and mind need to rest once in a while.
As Doug Nakashima, associate executive director at the Southwest YMCA in Saratoga, Calif., says, "Have a good time. Eat ice cream. It's OK. Life is too short not to enjoy it, and exercising is just one component of living healthy."
But numerous studies show the benefits of regular exercise -- more efficient muscles and blood flow and better overall aerobic capacity -- start to disappear after about three weeks of inactivity. Some measures of fitness can decline by 50 percent in that time.
"It's really hard on your system if you go on vacation, and you start eating differently, and you become sedentary and inactive," says Ms. Hanna. "You start out the next week, and you're heavier. You don't have much energy."
But Ms. Hanna doesn't mean you have to stow a stair-climber with the rest of the gear on top of the Winnebago. Instead, she and others have simpler tips for vacation fitness.
1. Get out of the car.
"Basically, as far as strength and cardiovascular conditioning go, you can do approximately one-third the amount of the exercise you usually do and maintain your fitness," says Mike Caton, fitness director at the Cooper Aerobics Center in Dallas. "That's the rule of thumb."
That is, if you usually run 21 miles a week, you can run about seven miles a week and maintain your level of fitness, Caton says.
Walking also is good.
"I don't think there's anywhere you can't walk," says Bernice Alaniz, director of community relations for the Metropolitan YMCA in San Jose, Calif. "Unless you were on a little tiny sailboat."
2. Pack your mobile fitness center
While many hotels are equipped with fitness centers, provide VCRs and exercise tapes and pass around maps of nearby running routes, no-frills travelers will have to construct their own gyms.
The Body Firm's Ms. Richardson, who sees vacation as an opportunity to exercise even more than usual, takes along her running shoes, her bicycle, even her free weights. But if she had to be limited to one fitness item it would be this: a big rubber band.
"They take up no room and no weight and they cost about 25 cents at any stationery store," she says. "Hook two or three together, and they give you great resistance."
"You can work every major muscle group with that band," says Ms. Richardson.
Jump ropes are handy for people who are in good cardiovascular condition and want to stay that way. In fact, a jump rope is one of two pieces of equipment in the Apple Computer Inc. "fit kit," which traveling employees can borrow for business trips.
You can always do some stretching and strength-building exercises, such as push-ups and stomach crunches, in your room.
"And the hotels are going to love this," says Ms. Richardson, sounding reluctant to reveal all of her secrets, "but I've also bopped around on the beds. It's quiet. If you jump around on the floor, you annoy the people below you."
3. Budget for a gym
Let's say you cannot bring yourself to bounce on your hotel bed. Think about including money for gym drop-in fees in your vacation budget.
Many gyms will allow you to use the facilities for a daily fee that usually runs between $3 and $10.
Before you leave home, ask if your own gym has agreements with any others that allow members to use facilities across the country. Many YMCAs, for example, allow visiting members from cities 50 miles or more away to use their facilities either for free or for a small fee.
4. Eat right.
You're on vacation. You deserve ice cream every night.
Well, maybe not every night.
"If I want the carrot cake or I want to try the flan, that's fine," says Gail C. Frank, professor of nutrition at California State University, Long Beach, and a spokeswoman for the American Dietetic Association. "But I will plan that around what I eat during the whole day, or two to three days."
5. Be flexible.
"Remember," says Rick Valdez, health and fitness director of the Central YMCA in San Jose, "it's all about having fun."
If you're used to working out on a treadmill, consider renting a bicycle and sightseeing from the bike path. Take the kids to the swimming pool or lake in the area and get in a few laps yourself. Rent in-line skates or take a rock-climbing class.