CHARLOTTE -- Hot flashes. Headaches. A tummy that won't go away no matter how many crunches you do. Menopause can be especially vexing for women trying to lose weight. As their estrogen levels drop, their testosterone exerts more influence. Because of the ensuing havoc, a woman's body will do what it can to retain whatever stores of estrogen it has. Alas, estrogen is stored in fat.

Don't despair, says Leigh Shipman, an instructor with the Simmons branch of the Charlotte YMCA. She's been working with "active older adults" for 17 years, and she's seen both men and women lose weight and get fit. "The average American woman should do just fine with one hour of moderate exercise a day," says Shipman, 51.

The key is finding the right exercise regimen -- one you enjoy, one you look forward to doing and will stick with, says Mary Petters, an exercise physiologist with the University of North Carolina Wellness Center at Meadowmont in Chapel Hill. "There's something out there for everyone," says Petters.

We polled health and fitness experts Mary Petters at the wellness center, Leigh Shipman with the Charlotte YMCAs and Gerald Endress with the Duke Diet & Fitness Center in Durham, N.C., to find the most popular exercise classes for women 50 and older at their facilities.

1. Zumba: This Latin dance workout originated in Colombia in the 1990s and then became popular in the U.S.

Benefits: It's an aerobic workout that gets you sweating, gets your heart rate up, burns calories, and it's fun.

Why it's popular with the 50-plus set: Unlike other dance and aerobic routines, Zumba is less choreographed, more free-spirited.

2. Water aerobics /swimming: Ten years ago, says Endress, water exercises focused on folks with arthritis and other joint issues. That's changed. "Water aerobics has really taken off -- it's a much more vigorous exercise."

Benefits: Good cardio, good toning.

Why it's popular with the 50-plus set: Exercising in water relives pressure on joints.

3. Walking: This is the preferred exercise for 25 million women 45 and up, making it by far the most popular form of exercise for that group.

Benefits: A vigorous daily walk of at least 30 minutes can manage weight; control blood pressure; decrease the risk of heart attack; boost "good" cholesterol; lower the risk of stroke, breast cancer and type 2 diabetes; and protect against hip fracture.

Why it's popular with the 50-plus set: You can do it on your own schedule, it's cheap, and it can be a social activity.

4. Pilates: Exercises done with or without equipment that focus on core strength, flexibility and balance.

Benefits: It can make you leaner and stronger, but the benefits also can help people move more gracefully and efficiently, making it possible to do some of the basic functions of day-to-day life that can become a challenge as we age.

Why it's popular with the 50-plus set: It's adaptable. Pilates classes can be grueling enough to benefit a professional athlete or scaled back.

Getting started

--Consult a nutritionist and a trainer. A nutritionist can help you get a handle on what you really are eating and what you should be eating, says Endress. "People say, 'I don't eat a lot,' then they start writing down all the Starbucks coffees they have," says Endress. "They can even overeat fruit -- an apple has 100 calories." Likewise, says Petters, a good trainer can help you look at your lifestyle and see what realistically will work for you.

--Mix it up. "The body gets used to what you're doing," says Shipman, "and after a while it won't work as hard. You need to challenge it to work the muscles differently." For instance, you may walk on Monday, Wednesday and Friday, and take Pilates on Tuesday and Thursday.

--Achieve a "moderate" pace. You need to push yourself, though not at first, says Petters; it's good to work into a new routine. But to get stronger and lose weight, your body needs to be challenged. "If you're not sweating, your heart is not getting the workout it needs, and you're not burning the calories you need to burn," Shipman said.