On Wrist Use

In terms of size and design, the Polar A370 is between a small slender fitness tracker and a more substantial watch. Bands come in two size options: small and medium/large, and are available in black and a range of other stylish colors. It has a color touchscreen, but also includes a side button that helps move easily between selections on the screen. We found the bright images on the screen are clear to see even in the daylight and the navigation between features is intuitive. Scrolling is limited to up and down, rather than including any additional side-to-side options to explore. Press the “My Day” icon to see a breakdown of steps taken and calories burned, as well as the data from your latest workout and previous night’s sleep. Simply press “My Heart Rate” to check out your current resting or moving state, and “Training” to begin tracking a sport-specific workout. While the watch has an impressive sleep tracking feature, we found that it’s not the most comfortable device to wear overnight.

Software Support

The Polar Flow app is simple to connect with the Polar A370 and shares a complete view of the user’s activity, sleep, and workout data over a period of days, weeks, and months. Like the fitness tracker itself, the app is designed with simplicity of use in mind while offering full details on a full scope of wellness. We found it easy to compare full day statistics of workouts and sleep stats with other days.To get a complete week of daily activity feedback on the app, the user must wear the tracker for more than 10 hours a day on a least 5 days, not including sleep or rest. A feed on the app can give the user access to the training efforts of others, and the user can set goals and create training plans on the Polar Flow website which are then available to access within the app.

Battery Life

Polar says a fully charged A370 will last four days of fitness tracking. We were able to get about two days out of the tracker in full use, and a day or so more when phone notifications were turned off. Users are able to charge the fitness tracker with a micro USB port, so no brand-specific cable is needed.

Features

We found Polar’s Sleep Plus intelligence system to be the most notable feature on the A370. The tracker monitors total sleep duration and connects with the Polar Flow app to show wearers details like when they may have been disturbed during the night. The 24-hour activity clock in the app displays an easy-to-read breakdown of activity and rest over a full day and night, which can then be compared to other days documented during the week. These features gave us perspective on whether or not we were getting sufficient rest for high levels of active output. The fitness tracker is also waterproof up to 30 meters. Phone notifications can vibrate the tracker for a subtle alert on the wrist.

Accuracy

The Polar A370 had moderate accuracy with steps and heart rate. In one instance, a tester found the tracker didn’t indicate a high enough heart rate on a high-intensity interval training day. Her highest heart rate was tracked by a reliable device at 190 that day during a steep uphill anaerobic interval sprint, and the Polar tracker didn’t indicate a heart rate higher than 169 beats per minute during that workout. The tester found the Polar tracker more accurate with heart rate throughout the day. She counted her heart rate at her desk after recovering from a morning workout to find that 70 beats per minute counted was tracked by the watch at exactly 70 bpm. For steps, the tester counted 500 steps and the Polar A370 tracked 491. Like the other trackers, the count of steps throughout the day would increase even when testers were not walking, but would still create a reliable reference point for movement levels.