In the Milky Way, about 1 in 5 stars that are like our sun in size, color and age have planets that are roughly Earth's size and are in the habitable zone where life-crucial water can be liquid, according to intricate calculations based on four years of observations from NASA's now-crippled Kepler telescope.
Varying Incline. Varying the incline is another option for interval training using a good treadmill. Exercisers that want to vary the incline for interval training should still start with a warm up period, which should be a walk or slow jog at an incline of 1.0.
The treadmill and the elliptical trainer are two of the most popular cardio machines, but choosing which one is best can be a daunting task. This is especially true for those with arthritic knees. Both the treadmill and the elliptical trainer simulate a natural walking or running motion. On a treadmill, you run in place while a belt moves under you. On an elliptical trainer, each foot is placed on a platform that you move in an oval-shaped motion.