Losing weight is supposedly simple. Just burn more calories than you eat, right? That may seem like an easy recipe, but millions will attest that shedding extra pounds is often easier imagined than accomplished.

The fact remains that exercising is still a key aspect of losing weight and toning up. Consider this research published in the scientific journal Medicine & Science in Sports & Exercise: Scientists found that a mere hour of aerobic exercise is all it takes to jumpstart accelerated energy and calorie-burning on the cellular level. Put another way, exercise burns more calories and conditions the entire human body to burn energy more efficiently. So, while a single jog or run may not instantly lead to six-pack abs, each bout of exercise is absolutely making a difference.

"It's pretty remarkable that even after just one hour of exercise, these people were able to burn off a little more fuel," says lead study author Matt Robinson, an assistant professor in the College of Public Health and Human Sciences at Oregon State University. "From a big picture health perspective, it's very encouraging for people to realize that you can get health benefits from a single session of exercise. We're trying to encourage people, 'You did one, why don't you try to do two? Let's do three.'"

Still, if you can't help but think there must be a way to burn a bit more calories on average while getting in some cardio, we have some good news! Doing this one thing while running can help double the amount of calories burned. Keep reading to learn more, and next, don't miss This Workout Is Three Times Better for Your Health Than Walking, New Study Says.

Consistency is usually a positive across most areas of life, but plenty of relevant scientific research tells us that varying up cardio exercises with interval training is a great way to burn more calories. Often referred to as HIIT (high-intensity interval training), this approach to cardio is all about combining intense, short bursts of motion with longer periods of rest or "cooling down."

It may sound counterproductive to slow down while out for a run, but engaging in interval training activates both the aerobic and anaerobic systems within the body, creating an oxygen shortage that promotes greater and more prolonged calorie expenditure. "There's nothing wrong with steady-state cardio, but I would suggest adding sprint intervals to your cardio workout to bump up the burn," Gunnar Peterson, celebrity PT, told NBC News.

Still skeptical? Take a look at this study published in The Journal of Strength and Conditioning Research. The research team measured and compared calories burned during a 30-minute bout of HIIT, regular cardio, and weightlifting. Sure enough, the HIIT cohort ended up burning 25-30% more calories than the other groups.

Another study released in the Journal of Applied Physiology concludes that interval training increases the amount of fat burned during an hour of exercise by as much as 36%. Not to mention a 13% overall increase in cardiovascular fitness. Over the course of 10 sets, participants engaged in cardio at 90% effort for four minutes at a time, followed by two minutes of rest.

Related: This Workout Plan Will Keep You Lean Throughout the Holidays.

HIIT also minimizes the time we spend exercising while maximizing the health benefits. HIIT workouts can be finished in as little as 15 minutes, but often burn more calories than traditional cardio routines lasting twice as long if not even longer.

One study released in The Journal of Applied Physiology even reports that just a few 30-second intense sprints improve overall fitness just as much as a full hour of jogging!

Circling back to the first study mentioned above, keep in mind that participants assigned to the HIIT group not only burned significantly more calories than the others but also accomplished this while exercising for a fraction of the time. While everyone else had to work out for 30 minutes straight, the HIIT exercisers only moved at maximum intensity for 20 seconds at a time, followed by 40 seconds of cooling down.

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HIIT can even help you burn more calories while you're lounging on the couch. Calories burned while at rest are referred to as EPOC, or post-exercise energy consumption. Well, according to the American Council on Exercise, HIIT is the single best way to jumpstart EPOC!

Similarly, this research tells us that just a couple of minutes of intense training (spread out across 25 minutes of interval training) promotes increased calorie-burning for the entire rest of the day. Subjects in this study burned as much as 200 extra calories during workout days despite only exercising vigorously for about two and a half minutes total. With these extended calorie-burning benefits in mind, burning double the calories via HIIT doesn't sound so far-fetched after all.

Related:Secret Effects of Lifting Weights Just Once Per Week, Science Says

If you're still on the lookout for more ways to reap further fitness rewards from running, consider going out for your daily jog first thing in the morning before sitting down for some breakfast.

This study published in The British Journal of Nutrition found that going for a morning run on an empty stomach results in nearly 20% more fat burned! More research published in The Journal of Clinical Endocrinology and Metabolism came to similar conclusions, reporting that a pre-breakfast workout burns twice as much fat.

For more, check outThis 5-Move At-Home Workout Will Help You Build Strength.

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Doing This One Thing While Running Burns Twice the Calories, Science Says Eat This Not That - Eat This, Not That