Most exercise machines have a console displaying the calories burned. Because treadmills have been around for a long time and their console's algorithms have been tested on numerous subjects, they're "more likely" to be accurate than other exercise machines, the American Council on Exercise states. But factors that aren't measured by the machine, such as body fat and fitness level, also affect the calories you burn. Don't just trust the number on the display: Learn how you can adjust your speed and time to burn more calories during your workout.
Increasing your speed will help you improve your endurance and burn more calories. For example, if you weigh 160 pounds and work out for an hour, you'll burn about 861 calories running at a speed of 8 mph, around 606 calories at 5 mph and just 204 calories if you walk at a speed of 2 mph. Run at a speed you can maintain -- if you're too tired to hold your pace, you won't burn as many calories. Overtraining can lead to soreness and even injury, so if you've been on the treadmill for a long time and start to feel exhausted, try a lower speed or stop and take a break until the next day.
You should get at least 150 minutes per week of moderate-intensity aerobic activity or 75 minutes per week of vigorous aerobic activity, MayoClinic.com suggests. You can break these workouts up into short intervals, but each interval should be at least 10 minutes long if you want to gain health benefits and boost your metabolism enough to burn calories. Exercising for longer will burn more calories, but this won't hold true if you become too tired to maintain your pace.
Instead of just running for a long time at a high speed, try interval training -- run for short bursts at a very high speed interspersed with periods of slower speed. Interval training will improve your aerobic capacity, allowing you to use the treadmill for longer without getting tired. Intervals will also allow you to burn more calories in a shorter amount of time, maximizing your workout.
Take your heart rate during the peak point of your workout, as a higher maximum heart rate indicates that you're exerting more energy and burning more calories. To determine your level of workout intensity, try the "talk test" suggested by the President's Council on Fitness, Sports and Nutrition. If you can hold a conversation without too much difficulty, you're working out at a moderate level of intensity; if it's difficult to get more than a few words out, you've reached a vigorous level.
- MayoClinic.com: Exercise Intensity
- MayoClinic.com: Exercise
- ACE: Are the Calorie Counts on Exercise Machines Accurate?
- MayoClinic.com: Rev Up Your Workout With Interval Training
- President's Council on Fitness, Sports and Nutrition: Physical Activity Guidelines for Americans
- Centers for Disease Control and Prevention: How Much Physical Activity Do Adults Need?
Natasha Hochlowski holds a dual B.S. in chemistry and writing from Loyola University Maryland. She has been writing professionally since 2007, frequently contributing to "The Journal of Young Investigators," and has worked as a technical writer/editor for several major pharmaceutical companies.