Mio Alpha Heart Rate Sport Watch

Mio Alpha Heart Rate Sport Watch

Unlike most "smart watches" the Mio Alpha is stripped-down: It doesn't have a barometer, or internal GPS, and it can't tie your shoes for you. It does, however, accurately measure your heart rate without a chest-strap sensor – something the athletic community has been waiting for since the early days of heart-rate-based training.

Two bright green LED lights and an electro-optical cell located on the underside of the watch determine rhythmic changes in your blood volume. This information is then analyzed against data acquired by a separate motion sensor to produce an accurate reading, even while moving at speeds up to 12mph. The Mio Alpha doesn't keep track of your training patterns, but using Bluetooth 4.0 it can transfer data to your smart phone, which can then be analyzed by apps such as Endomondo or Wahoo fitness.

We found the Mio to be highly comfortable. The supple silicone didn't bother us during a recent early morning circuit, and the low profile casing means there weren't any jutting buttons digging into the back of our hand while lifting.

In heart rate mode, the watch's eight- to 10-hour battery life should be able to outlast any workout. Admittedly, we've had to recharge it already due to putting it to a different use over the past few days: Attempting to lower our heart rate through meditative practice. Getting below 40 beats per minute is proving challenging. [$200; alphaheartrate.com]