I tracked my sleep on a smartwatch, a smart ring, and Whoop: Here's what I learned
by Sanuj Bhatia · Android PoliceThe fitness tracker market has evolved significantly in recent years, offering options in all shapes and sizes. From traditional smartwatches like the Apple Watch and Pixel Watch 3 to fitness bands like the Xiaomi Smart Band 9, there's something for everyone. We're also seeing newer forms of wearables like smart rings, such as the Samsung Galaxy Ring and Amazfit Helio Ring. There are also dedicated fitness trackers like Whoop.
Most of these devices include sleep tracking features, but are they truly effective? And how do their sleep tracking capabilities differ? Let's take a closer look.
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A quick look at the three wearables
What each of these trackers brings to the table
For this test, I chose one top wearable from each category. For the smartwatch, I went with the Apple Watch, which offers a balanced approach to health tracking, similar to the Samsung Galaxy Watch 7 and Pixel Watch 3. It's priced competitively within the category and represents what most people think of when they picture a smartwatch with reliable health tracking features.
For the smart ring, I selected the Amazfit Helio Ring. It's one of the most affordable options in its category, especially since the company dropped its price to $199. This makes it an attractive choice for anyone looking to explore health tracking without a huge investment, and the Amazfit Helio Ring provides a comprehensive sleep tracking system, including sleep scores, in-depth monitoring, and an AI-powered sleep coach.
Lastly, I included the Whoop 4.0, which is widely regarded as the gold standard for fitness and recovery tracking. Although it's worn like a smartwatch, Whoop lacks a display and focuses entirely on monitoring your metrics 24/7. It stands out for its subscription-based model (costing up to $240 per year), but it offers the most detailed sleep and recovery data of the three.
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A few things to note before we begin
Before we dive in, there are a few things you should know. I wore all three wearables every night for a week, sticking to a consistent schedule — sleeping from around 2am in the night to 10am in the morning. (Not ideal, but it comes with the job).
It's also important to understand some key terms that will come up later. These terms are essential for understanding sleep tracking, and I found all of them present across all the wearables I tested. Knowing these will help you better understand the data each device captures and how they compare. Here are some key terms to keep in mind:
- Sleep stages: These are distinct phases your brain and body go through during sleep, including light, deep, and REM sleep.
- Heart rate variability: The variation in time between heartbeats, reflecting your body's recovery, stress levels, and overall readiness.
- REM cycles: The periods of Rapid Eye Movement sleep, crucial for cognitive function and emotional health.
But, also keep in mind that these sleep quality metrics can be subjective and interpreting the data may vary from person to person. What works for me might not work exactly the same for you, but it should still provide a solid reference point for understanding each device's performance.
Which sleep tracker is the least intrusive?
You can probably guess, but here's why
When it comes to comfort, it's no surprise that the Amazfit Helio Ring is the clear winner. I'm not someone who likes wearing anything to bed (except for the sake of this test), but if I had to choose a tracker to wear every night, it would be a smart ring. It's so unobtrusive on your finger that you almost forget it's there, yet it delivers comparable results to bulkier devices, which still amazes me.
Comparing the Apple Watch and Whoop, it's a close call. I initially expected the Whoop to be lighter since it doesn't have a display and is just a band with sensors, but it feels almost as heavy as the Apple Watch. Personally, I find both a bit uncomfortable to wear on my wrist while sleeping — they feel bulky and cause slight discomfort in the morning.
However, this can vary depending on personal preference, and you might find a fitness band or smartwatch more comfortable than a smart ring.
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Which tracker gives the best sleep insights?
Which tracker does a better job of breaking down your sleep
Now, let's break down the output of the three wearables. Both the Amazfit Helio Ring and Whoop provide a sleep score to summarize your rest, while the Apple Watch does not. Instead, the Apple Watch presents raw data like sleep duration, stages, and heart rate variability.
While detailed data can be valuable, a simple sleep score is often more practical for a quick assessment, helping you decide whether to push through a workout or take it easy. This feature is available on most Wear OS smartwatches, so the Apple Watch's lack of a sleep score could be a downside for those seeking quick insights.
I also noticed a significant difference in sleep duration readings. The Whoop consistently showed lower sleep durations compared to the Apple Watch and Helio Ring, which reported similar results. I found the Helio Ring's readings to be closest to how much sleep I actually felt I got.
This discrepancy is likely due to each device using different algorithms to interpret sleep data. Whoop, for example, seems to be more sensitive to minor movements, counting them as wake time, which could explain the shorter duration.
| Metric | Amazfit Helio Ring | Apple Watch | Whoop |
|---|---|---|---|
| Average Score | 78.0 | 67.4 | |
| Average Duration | 7hrs 18 min | 7hrs 14 min | 6hrs 31 min |
| Average Deep Sleep | 1hr 29 min | 1hr 04 min | 1hr 06 min |
| Average REM Sleep | 1hr 33 min | 1hr 24 min | 50 min |
| Heart Rate (bpm) | Avg: ~61 | Avg: ~50-100 | Avg: ~60 |
| Respiratory Rate | Avg: ~15-25 | Avg: ~17.2 |
Interestingly, the Watch and Whoop tracked deep sleep similarly, while the Helio Ring was slightly off. On the positive side, both the smart ring and Whoop reported nearly identical average heart rates, which shows that the Helio Ring's smaller sensor can still accurately capture heart rate data throughout the night.
However, raw data alone doesn't tell the whole story. What's equally important is how each device presents the data and how useful it is in helping you make decisions. For example, I love how Whoop places your sleep metrics front and center in its app, along with the AI-powered Whoop Coach, which lets you ask questions about your sleep and gives tailored advice — even if you're not familiar with the detailed metrics.
Similarly, Amazfit's Zepp app provides a sleep score and a daily insight right on the home screen, offering a quick summary of your sleep quality and suggestions on how to approach your day. It also considers your past sleep trends and offers a service called Zepp Aura, which now comes free. This service provides detailed sleep reports, sleep apnea detection, and an AI coach similar to Whoop.
In contrast, the Apple Watch app mainly displays raw data like sleep duration and stages. While I found its sleep data to be quite accurate compared to my own experience, it doesn't go beyond just showing trends and comparisons. There's no AI integration or quick summary score to make the information more actionable — at least for now.
Which wearable comes out on top?
If you're serious about fitness and want to track not just sleep, but also overall body recovery, the Whoop 4.0 fitness tracker is hard to beat. It's in a league of its own, particularly with its AI coach. But if, like me, you find it uncomfortable to wear anything on your wrist at night, a smart ring like the Amazfit Helio Ring is a better fit. It provides a clear sleep score, AI coaching, and even sleep apnea detection in a more comfortable form factor.
On the other hand, if you're just curious about sleep tracking, your existing smartwatch might be a good place to start. Most smartwatches have improved when it comes to sleep tracking, although wearables without displays still provide the most in-depth sleep tracking experience.
Amazfit Helio
$199 $299 Save $100
The Amazfit Helio Ring is a classic-looking titanium ring that contains activity and heart rate sensors. It can tell you how far you walked and how you slept, all in a package that is as unobtrusive as a plain wedding band. While sizing and battery life could still use some improvement, the $100 price cut and removal of subscription fees make it a much more appealing option.
Whoop 4.0
The Whoop 4.0 is a fitness tracker designed for serious athletes and fitness enthusiasts. With 24/7 heart rate monitoring, sleep tracking, and daily recovery insights, it provides a complete picture of your health. Its lightweight design, accurate data, and coaching features make it an ideal training companion.