It's a fact. Treadmills burn more calories than any other piece of fitness equipment.* In test after test, treadmills consistently burn more calories than steppers, rowers and bikes. There simply isn't a more effective cardiovascular workout. Besides high marks in the calorie-burning column, the healthy benefits of walking and running are well documented as well.
When buying a treadmill, here are some things to keep in mind:
Motor: The continuous-duty rating is the motor's true continuous horsepower, not just it's "peak" horsepower. So a 2.0 continuous-duty HP motor is actually more powerful than a 2.0 HP motor not rated as continuous duty. For good wear, Look for a motor with at least 1.5 continuous-duty HP. Most home units are DC. Some commercial treadmills are AC, which tend to be noisier and require a dedicated power line.
Speed: Most treadmills run from 0 to 10 mph. A safe starting speed is always an important safety feature. Treadmills designed for more serious jogging or running go up to 12mph. Some offer one-touch speed buttons to adjust speed quickly and easily.
Belt and Deck: Be sure the length of the treadbelt is long enough for your longest stride. The width of the belt should be at least 16", although wider belts allow for more comfortable strides. Likewise, longer decks allow for a more comfortable stride. Two-ply belts are stronger and less likely to curl at the sides. Quality decks shouldn't need much maintenance and operate at low temperatures.
Impact Absorption: Treadmills usually absorb some of the force from the impact of your feet. Some use cushioning under the belt, others have cushioning in the belt itself. Some even offer electronic adjustable cushioning. The lower the impact, the better.
Incline: The incline can range from 0% to about 15%. A wider range is the best choice. The most high-tech treadmills offer incline that adjusts according to the exerciser's heart rate. Others have automatic electronic incline with the push of a button. The electronic incline should not be noisy or cause trembling. The least favorable are those that require manual adjustment before starting your workout.
Control Panels: Electronic feedback displays of speed, time, and distance are generally standard on most treadmills. Some also display calories burned, heart rate, incline or workout history. Most treadmills offer preset and/or custom programs you can design yourself. Control panels range from a simple display to fully programmable consoles with high-tech features, such as the ability to run programs from the Internet. Price is influenced by the control panel options, so purchase only what you will regularly use.
Heart Rate Monitors: Many treadmills include some type of electronic heart-rate monitor that enables the user to stay in his target heart rate without having to stop and manually take a pulse. Chest-strap monitors tend to be the most accurate. Thumb pulse, ear clip and other strap methods are also available, but less precise.
Frame: High alloy, welded steel with a protective coating to avoid rust is the way to go. Avoid weaker materials and bolted frames.
Hand Rails: Some treadmills are designed with a handlebar in front, some with side rails. The location is a matter of preference.
*Journal of the American Medical Association; May 8, 1996; Energy Expenditure with Indoor Exercise Machines; Anne I. Zoni, DO; Martin D. Hoffman, MD; Philip S. Slifford, PhD. Also reported in USA Today.