Beyond simple vanity, you know the reasons to exercise. Lack of physical activity increases your risk of a long list of serious ailments, including anxiety, arthritis, breast cancer, colon cancer, dementia, depression, type 2 diabetes, heart disease, hip fractures, obesity, osteoporosis, and stroke. The federal government recommends that you exercise for 150 minutes a week. Just 30 minutes of sustained anything, five times a week. Yet half of American adults fail to manage it. Even if you do exercise regularly, the routine can quickly feel like a rut.

So Chicago asked a bevy of top-notch local fitness experts to cook up game plans to beat four common fitness challenges, one of which is likely to be yours. What if you’re a total beginner? What do you do when your trusted workout stops giving the results you expect? How about when you’ve plateaued on a steady diet of cardio and yoga? And the biggie: How do you get over a chronic lack of motivation, also known as sit-on-the-couch-itis?

Four willing subjects in the city and suburbs—two men, two women—followed the plans for 12 weeks. Turn the page to see the results they got. (Spoiler: They all lost weight and inches!) We also tapped Gretchen Swank, a dietician at Northwestern Executive Health and a certified specialist in adult weight management, who gave each person three easy-to-follow diet fixes.

Gym workouts are key elements of all four routines. It could hardly be otherwise, given that Chicago’s weather makes indoor exercise a necessity for a big chunk of the year. For this story, we researched every full-service gym in the metro area. (To be considered, gyms had to offer, at a minimum, weight rooms, cardio equipment, group fitness classes, locker rooms, and public membership—no private clubs.) The result: a ranking of the five best top-of-the-line gyms and the five best bargains.

Speaking of bargains, for many of us, getting and staying fit has never been less expensive. A growing number of employers are rewarding workers who exercise with lowered health insurance premiums, discounts on gym memberships, and points to redeem for heart monitors and other prizes. (Ask your company’s benefits department about such deals.) This fall, Chicago-based Health Care Service Corporation, the parent company of Blue Cross and Blue Shield of Illinois, will hand out bonuses to employees who get their BMI, waist circumference, and blood sugar and cholesterol levels checked.

Even if you don’t have a financial incentive egging you on, you can take advantage of other motivators. Bonnie Spring, the director of the Center for Behavior and Health at Northwestern University, says simply monitoring your exercise raises your fitness awareness. So any device or technology that helps you do that, she says, is a good investment. MapMyFitness is a popular—and free—app for the iPhone that uses the phone’s GPS feature to track how far you’ve run, biked, hiked, or walked. Spring also recommends pedometers, like the Fitbit Zip ($60, fitbit.com), a wearable activity-tracking gadget that wirelessly syncs with a personal progress report on your computer.

But perhaps the best motivator is low-tech: a workout buddy. “You go to the gym because you told someone you’d do it,” Spring says. Once there, take full advantage of the perks, such as huge TVs and fancy lotions in the locker room. “You can get somebody to change by pairing a new behavior with something that’s rewarding,” adds Spring. “It’s a reinforcer.”

Photography: Jeff Sciortino