If you and the treadmill first became friends because you were hoping to lose some pounds, you're in luck. The treadmill "can be an extremely effective tool for building aerobic capacity, burning calories, and developing your fitness level," Lee Wratislaw, a Gold's Gym trainer, told PopSugar. But, just stepping on the tread and hitting "start" won't necessarily burn off that pasta you had last night. Both duration and intensity matter. "HIIT [High Intensity Interval Training] sessions, comprised of shorter bursts at higher speeds followed by periods of active recovery or complete rest, are perfect ways to burn more calories in a shorter amount of time," Wratislaw said, adding that a 20 minute session of HIIT is enough to burn serious calories.

What if you'd rather just hit start, choose your preferred speed, and stay there? This technique is called steady state cardio, and to burn sufficient calories, you'll need to run for at least 30 minutes or walk for 40 minutes, according to Wratislaw. How many calories you'll burn depends on your size and your speed. A 30-minute jog at five miles per hour burns 240 calories for a 125-pound person, and someone 185 pounds would burn 355 calories from the identical workout (per Chron). Double that pace and both the lighter and heavier runner would more than double their burn.