Heart-rate monitors

Excellent accuracy and two CR Best Buys, one for as little as $40

Vigorous exercise might yield greater health benefits than moderate workouts. A heart-rate monitor can help you track the intensity and make sure you don't go too far outside your target zone. We tested 13 models, from $35 to $110, and found that most had excellent accuracy. But depending on your style of exercise, a chest-strap model might offer advantages over a wrist monitor.

Our test included eight chest-strap models, three wrist models, and one that can be used either way, plus a model worn on your finger. Our volunteers wore each monitor while exercising on a treadmill at various intensities. To assess accuracy, we compared heart rates on the monitors with those measured by an electrocardiograph, an accurate device that doctors use. We also sent staffers home with the monitors to see how easy they were to use.

Most will provide a consistently accurate heart-rate reading. The chest-strap models allow you to move freely, since you can get your heart-rate reading without touching anything. The wrist-only models require you to touch the device to get a reading. We don't recommend them for cyclists, and runners or swimmers might find them distracting.

How to choose

Use the Ratings (available to subscribers) and choose by price or features. If you cycle or run, choose a chest-strap model.