Priorities aside, the most effective workout schedule includes something cardio for your heart, something strength oriented for your muscles and something flexibility oriented for posture, relaxation and ease of movement. Aim for 10 to 60 minutes of cardio three to six times a week, at least two strength workouts a week and 3 to 5 minutes of stretching three to six times a week. When you're tight on gym time, choose the workout element that's most important to you and get creative about fitting in the rest of your exercise. A couple of 10-minute walks throughout the day will fulfill your cardio commitment. A set of push-ups while you're printing a report or 12 calf raises while you're waiting in line at the grocery store will fulfill your strength training needs. And a couple of stretches right before bedtime or during commercials will fulfill your stretching requirements.

Lynn Grieger, RD, CDE
By pumping up your heart rate while you're lifting weights (circuit training), you'll accomplish a lot in a short period of time. Warm up for 5 minutes on the bike or treadmill, and then start your weight-lifting circuit. Follow each set of weights with 1 minute of cardio activity such as jumping rope, doing jumping jacks or running in place. My local gym has stairs from the weight room to the cardio area, and I often see people moving from working on biceps to running up and down the stairs for 1 minute, then focusing on their triceps, etc.