Personal trainer Sam Kopf works out six times a week. And she always tries to monitor her heart rate.
"I wear a heart-rate monitor to keep myself honest, to make sure I'm working out at the appropriate level," Sam Kopf said.
Consumer Reports tested heart-rate monitors ranging in price from $35 to $110.
"We looked at several different kinds of heart-rate monitors. The most common are chest-strap monitors, which measure your heart rate via a sensor that's on a strap that you wear around your chest and then transmits the results to a wristwatch that you wear while you exercise, so you don't ever have to touch anything," Jamie Hirsh said.
With wrist-strap monitors, you have to touch the device with the fingers of your other hand to get a reading.
Also tested - a ring monitor from LifeSpan. Panelists wore the devices while working out a treadmill. This electrocardiograph confirmed the accuracy of the monitors. All proved accurate, except for the LifeSpan ring.
"Most of the monitors also have convenient features, like a watch and a stopwatch. With many of them you can also program in the maximum and minimum heart rates that you want to reach while you're exercising."
Those monitors alert you if you go outside your zone.
Panelists also evaluated how easy the monitors are to use. The 50 dollar Timex Personal Trainer chest-strap monitor rated excellent for both accuracy and ease of use.
Chest-strap monitors are best for working on a treadmill or when running or biking. But a wrist-type can be fine for walking.
Consumer reports says a good choice is the "Sportline Duo 1010, which can be used either as a chest strap or a wrist monitor. It costs $60.