Instead of: The heart rate monitor on a large fitness machine
Use: A heart rate monitor on your watch ($80 Polar F4 heart rate monitor at amazon.com).
Size: A watch and a strap to wear around your torso.
Expert says: Recent studies have found that the heart rate monitors and calorie counters on large machines such as treadmills aren't accurate, with some overestimating your stats by up to 42 percent. Since you're plugging in your specific data into your watch, you can be much more accurate.
"The heart rate is a very important part of training, because it is an indication of how hard you are working," Savion said. "Wearing a heart rate monitor will help you find the perfect intensity and pace for your workout. Use your monitor as your trainer." Set your watch to beep when you fall below your target.