How Long Should I Run on the Treadmill a Day to Lose Weight?

But if you're wondering how long you need to spend running on the treadmill to lose weight, the answer isn't so straightforward. The amount of time you need to spend on a treadmill to drop weight depends on your diet, your body composition and the specific treadmill workouts you decide to do.

​Read more:​ How Much Weight Can You Lose on a Treadmill After 6 Weeks?

Here's what you need to keep in mind when it comes to treadmill weight loss.

It's often said that in order to lose a pound of weight, you need to burn 3,500 more calories than you consume. While it's not quite that simple, you'll still need to create a calorie deficit to shed pounds.

Generally speaking, to lose two pounds a week, you'll need to create a deficit of around 1,000 calories a day. (If you're committed to "rapid" weight loss, it's good to keep in mind that the National Heart, Lung, and Blood Institute says that you shouldn't lose more than two pounds a week if you want to drop pounds the healthy way.) By far, the most effective way to do this is with diet and exercise together, not the treadmill alone; you wouldn't have much time for anything else!

Most people need to knock a minimum of 500 calories or more a day off their food and drink intake. You can accomplish this by swapping out one meal a day for something like a vegetable smoothie or a small salad, then make up the rest of your 1,000-calorie deficit on the treadmill.

As common sense indicates, the number of calories you burn running on a treadmill depends on a few variables: speed, incline, duration and the runner's body composition.

To get a baseline idea, consider that a 180-pound male will burn about 410 calories in a half hour of running at 6 miles per hour, or a 10-minute mile, according to the Calorie Control Council. (The more you weigh, the more calories you burn when exercising.) Running at 6 miles per hour is a solid speed, but not a sprint. That puts him at almost half the calorie deficit he needs to lose at a rate of two pounds per week.

So if you're actually ​running​ (as opposed to ​walking​), then 40 minutes or so on the treadmill a day can achieve half the calorie deficit you need to achieve your goals. (The same man burns 545 calories in 40 minutes at that same speed.)

​Read more:​ How to Do HIIT Treadmill Workouts — Plus, a 25-Minute Routine to Try

It's important to note that if you've been sedentary, then launching into 40 minutes of stone-cold running could make you prone to injury. It's also setting the achievement bar pretty high, and it's better to shoot for lower, more sustainable goals. Plus, the ideal fitness routine also includes resistance training to boost your metabolism and help you burn calories even while resting.

Running fast in short spurts (known as high-intensity interval training, or HIIT) burns calories, blasts fat and preserves muscle. And if you have a busy schedule, HIIT can help you reach your goals despite time constraints, according to a September 2014 paper in the journal ​Applied Physiology, Nutrition, & Metabolism.​

There are no fixed parameters, but HIIT involves bursts of high-intensity effort followed by equal or longer periods of rest, for example, one minute of fast running followed by two to four minutes of walking.

It's a lot easier to run these calorie-torching intervals on the treadmill than it is outside: You can easily set your speed and increase your incline at the touch of a button. You can monitor your intervals without buying a fancy fitness tracker, and since treadmills are naturally indoors, you don't need to worry about rain, snow or heat getting in the way of your workout.

But even though running on the treadmill can certainly help you lose weight if you enjoy it, it's not the only tool you have in your weight loss arsenal. Focus on your diet, mix up your workouts and opt for steady, sustainable weight loss with the help of the treadmill. Your waistline (and sanity) will thank you in the long-run.