Remember: to lose a pound a week, expend 500 more calories than you’ve taken in. Here’s how to burn 500 calories through workout routines.

Swimming: Whether you're training for your first triathlon or burned out on cardio machines, swimming is an excellent head-to-toe workout (700 calories burned in an hour!). Here's how to get started:

• Find a pool: Try a community center, YMCA, health club, or even a local community college. Many offer weekly times when anyone can swim.
• Start small: Do two full laps (back and forth equals one), pause to catch your breath, and repeat three times. Try to practice two or three times a week.
• Perfect your form: Use every other lap to do a different drill. Hold a kickboard to concentrate on your kicking, or swim with a buoy between your legs to work on your stroke.
• Build it up: When swimming 300 yards feels easy, increase your total distance by up to 10 percent per week. Join a masters team for built-in guidance and motivation (find one at usms.org).

The average calories burned in one day swimming can help you lose a pound - or more - per week.

Winter Sports Workout Routines:

Downhill skiing: Calories burned per hour: 418

Fitness tips: Skiing downhill is not only excellent aerobic exercise, it also builds stamina while strengthening your buttocks, quadriceps, hamstrings, calves and core.

Snowboarding: Calories burned during exercise: 330

Fitness tips: A terrific total-body toner, snowboarding works your core, hamstrings, quads and calves as well as the muscles in your ankles and feet as you twist to steer your board downhill.

Snowshoeing: Calories burned per hour: 557

Fitness tips: Trekking along winter paths in snowshoes, which distribute your weight evenly over the snow so you don't sink through, works the buttocks, hamstrings, quadriceps, calves, core and abs -- offering a more intense workout and calories burned during exercise than you'd get on most warm-weather hikes.

Cross-country skiing: Calorie burn per hour-long workout routine: 557

Fitness tips: One of the best winter cross-training activities for runners and cyclists, cross-country (or Nordic) skiing is easy to learn and an excellent cardiovascular activity. It tones the buttocks, quads, hamstrings, calves, chest, lats, shoulders, biceps, triceps and abs.

*Calorie estimates are based on a 145-pound woman.