I hate wearing a watch to bed but want to track my sleep — the Garmin Index Sleep Monitor is the wearable I've been waiting for

Garmin Index Sleep Monitor: Review in brief

As much as I love my Garmin Forerunner 255, I don’t particularly love wearing to bed. So I was delighted to find out back in June that Garmin was releasing a specialized sleep tracker, and here it is: the first of its kind from the brand known for producing some of the best fitness and running watches on the market.

Rather than being a wrist-worn tracker, the Garmin Index Sleep Monitor is worn on your upper arm. It's a screenless sleep tracking device that sits in a machine-washable fabric armband, and is focused purely on sleep tracking and keeping tabs on your sleep stages, heart rate variability (HRV) status, blood oxygen saturation, breathing rate, skin temperature and overall sleep quality.

Although you don’t need a Garmin watch to benefit from the Sleep Monitor, it's best paired with a smartwatch you can wear by day to get an accurate reading of your overall health and recovery status.

At $169.99 it’s not outlandishly expensive, although it's maybe a little overpriced for a single-purpose tracker. You can get basic sleep and health trackers for around $100 elsewhere, but if you want to get into the nitty gritty of your sleep health, I'd recommend the Garmin Index Sleep Monitor.

Now that I’ve got my hands on one and subjected it to our thorough sleep tracker testing methodology, ahead you’ll find my honest thoughts on the Garmin Index Sleep Monitor, how it compares to other sleep tracking wearables and whether I think it’s worth the $169.99 it sets you back…

Garmin Index Sleep Monitor: Price

The Garmin Index Sleep Monitor retails at $169.99/£149.99. This is a standard price for a comprehensive sleep tracker (compare with the Withings Sleep under-mattress tracker at $199.95 MSRP).

You can get cheaper health and sleep tracking wearables (think Fitbit Inspire 3 at $99.95) that you can wear day and night, but the metrics they offer are more basic than those delivered by the Garmin Index Sleep Monitor. While you’re limited to time spent asleep with budget trackers, you'll get a whole host of sleep data with Garmin.

Yes, it’s an extra expense when you can get devices that can track both day and night health metrics, but it’s a worthwhile upgrade for anyone like myself who dislikes wearing their fitness tracker to bed (or simply wants to charge it overnight without losing insights).

Garmin has recently introduced a subscription fee putting AI-powered insights and an enhanced performance dashboard behind a paywall. However, existing features in the Garmin Connect app remain free and there’s no real benefit to upgrading to Garmin Connect+ if you’re only using Garmin for sleep tracking.

The Garmin Index Sleep Monitor has been available for just over three months and I’ve yet to see it go on sale, so I’m intrigued to see if it’s discounted around Black Friday sales.

Garmin Index Sleep Monitor: $169.99/£149.99 at Garmin
Level up your rest and recovery tracking with this new Garmin device focused on sleep insights. It is available at $169.99/£149.99 MSRP and pairs with the Garmin Connect app for a holistic view of your health.

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Garmin Index Sleep Monitor: Design

The actual sleep tracker is a 1.6" x 1.5" x 0.3" monitor that sits inside a 70% nylon 30% spandex fabric armband. The band is available in two sizes (S-M and L-XL) and its faceless design is reminiscent of the likes of Whoop.

As soon as I touched the armband, I was impressed by how soft the material felt. Although it looks a wide bit of fabric to wear through the night, it’s super lightweight (weighing between 16 and 20 grams depending on the size) and so stretchy that you won’t even notice it on your upper arm through the night, which is a big bonus.

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The main reason I dislike wearing my Garmin watch in bed is because it feels clumpy on my wrist and is uncomfortable in a side-sleeping position. It also doesn’t feel hygienic wearing a watch to bed when I’ve worn it in germy public areas, worked out in it and sweated in it during the day. But these problems are resolved with this sleep-only monitor. It doesn’t leave my (clean) bedroom and it’s unnoticeable on my arm through the night.

This sleep-tracking monitor packs an optical heart rate sensor to track heart rate and HRV, a SpO2 sensor for blood oxygen saturation (Pulse Ox) and an accelerometer to detect movement and sleep stages. Together, these sensors give a well-rounded picture of your overnight habits, health metrics and measurable sleep quality.

Garmin Index Sleep Monitor: Features

Unlike the best Garmin watches which track and analyze athletic activities and day to day movement, the Garmin Index Sleep Monitor is a single-purpose sleep tracker worn primarily to bed.

Plugging the gap when you need to charge your smartwatch overnight, the tracker means you can get 24/7 health monitoring to get a well-rounded picture of your fitness, health and recovery.

Plus, the Garmin Index Sleep Monitor features a Smart Wake alarm, which uses vibrations to rouse you during a lighter sleep stage within a pre-selected 30-minute window. The sleep tracking sensors monitor your sleep stages by tracking heart rate and movement, and identify when you are in your lightest sleep stage. When it detects this light stage within your designated wake-up window, it sends gentle vibrations to stir you from sleep.

There are three intensities to choose from and a double tap on the monitor will snooze the alarm for 10 minutes, while four taps will shut it off.

The goal of this feature is to wake you up at the most optimal point in your sleep cycle. I’ve found this helps me wake up feeling less groggy and more refreshed and would take gentle vibrations over a blaring iPhone alarm any day.

You can set your smart alarm time in the Garmin app, tailoring it to different wake times throughout the week, in line with your individual sleep schedule.

Garmin Index Sleep Monitor: Sleep tracking

Let’s get down to the big question we’re here for: how comprehensive and reliable is its sleep tracking?

The Garmin Index Sleep Monitor captures a thorough range of metrics including total sleep duration, sleep stages, overnight heart rate, HRV and breathing variations, restless moments and skin temperature change.

The metrics derived from Garmin matched up with other trackers including the Withings Sleep under-mattress tracker, which we use as a control tracker in our testing methodology. With leeway of a few minutes, my sleep and wake timings identified by the two devices matched during my testing period.

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Additional metrics including average respiratory rate and overall sleep score also match too, showing the sensors in the Garmin Index Sleep Monitor are accurate in measuring what they promise to.

The Garmin Index Sleep Monitor is not only accurate compared with other wearable and commercial trackers, but also with the sleep diary I kept while testing. I found the metrics given by the Garmin Index Sleep Monitor reflected the night sleep I felt I had. Sleep and wake times aligned with my perceived timings and wake periods through the night show up in the sleep stage graph.

For reference, my bladder is a creature of habit and I wake up around 1:30am-2am almost every night (it’s just how my sleep cycle goes). Here, you can see the monitor has always picked up on this.

Score: 4.5 out of 5

Garmin Index Sleep Monitor: Performance

I used our thorough sleep tracker testing methodology over two weeks to asses whether the Garmin Index Sleep Monitor is a reliable, worthy sleep tracker and whether it can actually improve your sleep. Here's what I found...

Set up

What’s in the box? The monitor, the fabric armband it sits in, a standard Garmin charger and, of course, a handy instruction manual.

It’s a simple setup process that involves plugging the monitor into a power source and pairing it to your phone.

Admittedly, it didn’t connect immediately and I did have to troubleshoot (i.e. flick Bluetooth off and on a couple of times) to get it connected to Garmin Connect. Though, this could very well be a me problem, as my phone seems to play hard to get when pairing to any Bluetooth device lately.

Once it recognized the device, it paired in minutes and the app helpfully guided me through how to best fit my armband.

I immediately got an email after connecting the sleep monitor to my Garmin account, guiding me through getting started. It included links to Garmin’s in-depth page on sleep tracking and how to understand your sleep, sleep score and other metrics.

Then I just had to slide it on my arm and snooze away.

Score: 4 out of 5

App

Providing the armband is within range of your phone, it will automatically connect to upload your data in the morning. Removing the band is the key signal for it to initiate an immediate sync to the app.

The sleep data collected by the sleep monitor is integrated into the Garmin Connect ecosystem, sitting alongside your activity tracking, fitness and health metrics, body battery, menstrual cycle tracking and heart rate data.

In the sleep corner of the app there’s an interactive graph you can click through to see exactly what happens in your body at exactly which point of the night. For example, below you can see how my heart rate fluctuates through the night with the spike around 1:40am aligning with when I got up to go to the bathroom.

There’s also the Garmin Sleep Coach offering personal recommendations on your ideal sleep dose for that night (it will add time to account for recent sleep debt, or increased activity levels if you use a Garmin watch by day). There’s another bar graph here pitting your sleep need against the actual duration you got.

Score: 4 out of 5

Battery life

Garmin’s marketing material promises seven days of battery life, and in my testing period I actually found it out-perform its promises (big kudos).

I charged it fully before my first night of testing, which took approximately two hours, and it first died an impressive 10 nights later – after working a seven to eight hour shift per night.

It charges with a standard Garmin charging lead, keeping the bedside cables to a minimum for existing Garmin wearers.

Score: 5 out of 5

Garmin Index Sleep Monitor: Should you buy?

Personally, I love the Garmin Index Sleep Monitor and find it works well for me as a dedicated Garmin user (I track my runs, workouts and day-to-day activity with the Garmin Forerunner 255) who dislikes wearing a watch to bed but still wants a holistic view of my fitness, sleep and recovery.

Buy the Garmin Index Sleep Monitor if…

✅ You’re looking for superior comfort: It’s easy to forget about the Garmin Index Sleep Monitor on your arm once you’re asleep. No wrist pressure, no distracting watch face.

✅ You’re already a Garmin user: Sleep metrics sync smoothly with Garmin Connect, contributing to a more accurate body battery and fitness score (rest is an essential component of your health, after all).

✅ You want a sleep-only tracker: If it’s just your sleep you’re looking to track rather than every movement you make during the day, the Index Monitor is a great option.

Don’t buy the Garmin Index Sleep Monitor if…

❌ You’re tight on budget: At around $169, it’s a substantial investment for a device that only covers nighttime metrics. If you already own a smart watch that tracks sleep, this may feel redundant.

❌ You want daytime tracking: The Garmin Index Sleep Monitor is just that — a sleep tracker in isolation. It doesn’t track daytime activities, workouts, GPS or anything beyond sleep habits.