Running may seem simple, but it's more effective than you might think. One pound of fat takes about 3,500 calories to burn—and running for an hour can burn off as many as 600 calories! Start running with just one mile a day, and try adding on additional miles each week until you're up to 5 or 6 miles a day. (Before you begin any exercise routine, check with your doctor.) Running burns so many calories because you're working harder than when walking—you're accelerating and decelerating, which requires more energy. Also, when you run your body works against gravity instead of propelling itself forward (as it does while walking), which is more strenuous.

2) Aerobics/Step aerobics

Step aerobics burns a lot of calories. You’ll use your own body weight for resistance as you step up and down, increasing your heart rate and taking your muscles through a full range of motion. A 150-pound person can burn about 700 calories per hour during an aerobics class.

3) Aerobics

It’s no secret that cardio is one of the best ways to stay in shape and burn calories. But research has shown that you don’t need long, slow workouts or even expensive treadmills to reap those benefits. A 2012 study published in The Journal of Sports Medicine and Physical Fitness found that a high-intensity interval training routine improved participants’ cardiovascular fitness more than traditional aerobic exercise (3). For a similar approach, try cross fit training.

3) Racquet sports (tennis, squash etc.)

Ten-pin bowling, also known as duckpin bowling, can be a good way to burn calories in a short amount of time. A typical game of ten-pin bowling requires less than an hour and burns off between 200 and 300 calories. Another racquet sport that burns lots of calories is tennis. Running around between points helps you get your heart rate up and burn fat quickly.

4) Tennis

There’s a reason why tennis is one of the highest-paying sports in professional athletics. It burns an average of 700 calories per hour, which is more than what basketball (400 calories), hockey (500 calories) and soccer (500 calories) burn. Tennis combines aerobic exercise with hand-eye coordination—something that’s present in all sports, but tennis requires especially good reflexes and vision.

5) Basketball

Basketball is not only a fun sport, but also an excellent way to burn off some extra calories. In fact, studies have shown that playing basketball for as little as 15 minutes can help you burn up to 50 calories! Along with helping you get into shape, though, basketball can also teach you important skills that will benefit you no matter what career path you end up following. If your schedule isn’t very flexible, don’t worry—it is possible to play basketball even if your life is busy!