If you have 20 minutes a day to spare for exercise, get out your running shoes. Anything that gets your body moving is going to burn fat -- be it walking, cycling or running -- and running is one of the fastest ways to burn that fat. That said, though, there are some things you should know in order to maximize that 20 minutes and burn the most fat possible.
If you want to lose a pound of fat, you're going to need to create a deficit of 3,500 calories through diet and exercise. Typically, the more intense the exercise you're doing, and the longer you're doing it, the more calories you're burning. If you only have 20 minutes each day, expect to burn somewhere between 200 and 300 calories running at a moderate pace. Other factors get into the mix as well, though; typically, the heavier you are, the more calories you'll burn for the same type of activity. Also, the more intense the workout, the more calories you'll burn.
When it comes to intensity of exercise, running is among the top calorie burners. A rapid pace of 8 miles per hour will burn about 861 calories in an hour for a 160-pound person, and a whopping 1,286 in an hour for a 240-pound person, according to MayoClinic.com. If you're running at a more moderate pace of 5 miles an hour -- about a 12-minute mile -- the 160-pound person will burn 606 calories in an hour, while the 240-pound person will burn 905. Since speed -- which increases the intensity of your workout -- is so important for increasing your caloric burn, consider getting a speedometer watch that shows you how fast you're running. Then you'll be able to more accurately gauge your calorie burn and to work on increasing your speed over time.
Interval training can help you increase the intensity of your workout and can help you burn calories faster, according to MayoClinic.com. Interval training can take many forms, but the basic premise is to do intense exercise for a short period, followed by a slightly longer period of moderate activity, continuing the cycle several times. If you only have 20 minutes, try starting out with two minutes of running at that 5-mile-an-hour pace. Then rev it up and run at an 8-mile-an-hour pace for one minute, and complete the cycle six or seven times. Try this routine two times a week to stave off boredom and push yourself to new speeds. You can also increase the intensity of your run by adding hills into the route.
If you're running 20 minutes a day and you're still not seeing the results you'd hoped for, consider other factors that could help you burn more fat. First, take a look at your diet, and start counting calories. You're already burning a few hundred calories with your run, but you could reduce a few hundred more from your daily intake by cutting out sugary drinks, cooking more low-calorie dinners, or finding other healthy ways to reduce your daily calorie intake. Also consider adding weight training to your routine. Muscle burns calories more efficiently than fat, so if you only have 20 minutes each day to work out, replace two running days with lifting days, in which you work the major muscle groups of your legs, arms and core.
Nicole Vulcan has been a journalist since 1997, covering parenting and fitness for The Oregonian, careers for CareerAddict, and travel, gardening and fitness for Black Hills Woman and other publications. Vulcan holds a Bachelor of Arts in English and journalism from the University of Minnesota. She's also a lifelong athlete and is pursuing certification as a personal trainer.