Walking or running on the treadmill are both great forms of exercise. You'll give your heart rate a boost, burn calories and enjoy the feeling of knowing you are doing something good for your body. Exercising is important to add to your daily routine if you are trying to lose or maintain weight, but can sometimes be hard to do if the weather is bad or if you don't like to walk or run outside when it's dark out. Treadmills can be easier on your joints than the concrete as well. If you're want to try mixing up your treadmill workouts, this one can help you scorch 500 calories! How many calories you burn on the treadmill at 6 mph depends on your speed, weight and gender. You can see how many calories you burn using the treadmill at 6 mph using the calculator below.