The iFit Sleep HR is designed to live under your mattress.

Sarah Tew/CNET

Many fitness bands and smartwatches now have integrated sleep-tracking features. Not everyone -- including me -- wants to wear something on their wrist at night though. Which is where dedicated sleep-tracking devices like the iFit Sleep HR ($119) come in.

Created by an Israeli startup that was acquired by Utah-based Icon Health and Fitness (iFit's parent company), the Sleep HR disc is the size of a small plate and designed to live under your mattress. It's powered by an AC adapter that plugs into the Micro-USB port on the device. For optimal tracking, iFit says to place the sensor under your mattress "around the area where your outer shoulder will rest."

After properly positioning it, you download the companion app for iOS or Android, pair Sleep HR to your phone or tablet via Bluetooth and you're good to go.

I have a thick mattress, but that didn't seem to pose a problem for Sleep HR -- it detects through mattresses up to 20 inches thick. Also, the sensor is apparently quite sensitive, but has a narrow range, so it doesn't pick up your sleeping partner's respiratory and heart rates so long as it's properly placed under you.

The stats you get are quite detailed, including numbers for average heart and respiratory rates, how long it took you to fall asleep, how many times you woke up and how long you're in each sleep cycle, including light, deep and REM stages. The system generates a total sleep score for the night and scores are tracked over time and and can be viewed on a graph.

As an added bonus, you can set a "smart" alarm in the app and the sensor will look for the lightest part of your sleep cycle to wake you. That should make it easier to get out of bed.

My mattress is quite thick but the sensor still worked.

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One of the reasons for buying such a device would presumably be to improve both the length and quality of your sleep. To that end there's a journal feature in the app that tracks your presleep habits and has you toggle sliders based on whether you consumed alcohol or caffeinated drinks, consumed a heavy meal or worked out. You can also add additional notes, such as "Took two Advil."

The idea is to monitor -- and perhaps improve -- your presleep habits in an effort to raise your sleep score over time. If nothing else, it makes you pay attention to how much you've slept (or not). While I frequently found myself looking at a middling sleep score (mid to high 60s, out of 100) in the morning, I did feel a sense of accomplishment when I hit the green zone, which starts at 85. I'm pretty much a C+ sleeper, but am working toward getting my grade up to a B.

One of my few really good sleep nights.

Sarah Tew/CNET

Activity trackers and smart watches are becoming more robust at monitoring your sleep and tracking your heart rate to determine how much time you've spent in various stages of sleep. But if you don't want to wear something on your wrist at night, or just want a device that's dedicated to sleep tracking, the iFit Sleep HR is certainly worth checking out.

There are cheaper solutions such as the Sleepace Sleep Dot ($50), which attaches to your pillow and doesn't seem to be as effective, and the Withings Sleep ($100), which shares some similarities to this product and is probably the iFit Sleep's closest competitor. With that in mind, I'd say that ideally iFit would figure out a way to get Sleep HR to $99. It's not a bad deal at $120, but I'd sleep easier knowing I paid less than $100 for it.

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