If you'd like to lose weight, running is regarded as a fairly efficient way to expend calories. It burns about 100 calories per mile if you weigh 150 pounds, depending on the terrain. If you'd like to work off even more calories on your run, the following are four ways to burn about 200 more:

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Hit the hills.

All miles aren't created equal, so if you're running uphill, you're exerting more effort and burning more calories.

Running on an incline of about 5 percent will burn about 50 percent more calories than running on a flat surface, so instead of avoiding hills, seek them out as you run. An easier way to achieve this, of course, is by using a treadmill. Even if you can't sustain an incline for the entire run, you can use it for short bursts.

Maintain a steady pace.

If you're running on a track or road, you may think you're holding a steady pace, but you probably aren't. So on a 30-minute run, for example, you may be lagging a bit and not running as far as you're capable of handling during that time period.

While you're logging in the miles, you may be able to do it more quickly and add a little distance if you use a treadmill for some runs. You'll be forced to stay at a steady pace, which may also help you maintain that pace even when you're running on roads or trails.

Add some bursts of speed.

Interval training involves alternating bursts of intense effort with lighter effort. If you're running, you might decide to go at your maximum intensity for a minute and then slow down considerably for the next two minutes.

You'll burn more calories during your bursts of speed, and the benefit will continue even after your run is over. That's because it increases your metabolism for the rest of the day. In fact, a study from Medicine & Science in Sports & Exercise found that women who ran in two-minute bursts followed by three minutes of lower-intensity running burned more calories in the next 24 hours than the runners who held a steadier pace. They even lost a small percentage of body fat in the next few weeks, while the women who ran at a steady pace did not.

Grab a medicine ball.

Running with extra weight can help burn additional calories, but it needs to be done in a way that doesn't strain your joints.

Shape magazine recommended that if you're on a treadmill, grab a medicine ball and hold it to your chest as you run. In addition to the extra weight, you'll be working harder - and burning more calories - since you can't swing your arms for extra momentum.