Why Garmin Index Sleep Monitor vs Whoop 5.0 isn’t a fair fight yet

Garmin’s Index Sleep Monitor is designed for overnight use on the upper arm. But its all-day comfort and continuous data sync have led to comparisons with Whoop. So is it a valid alternative?

The short answer is no. Garmin’s sleep band works well for what it is, but it doesn’t fully replace Whoop. Still, it’s closer than you might expect.

Where the overlap actually works

In terms of core metrics and sensors inside, the two bands aren’t all that different. You get detailed sleep tracking with stages, HRV, resting heart rate, breathing rate and skin temperature. Both support vibration-based smart alarms that aim for gentler wake-ups. While the Index is worn on the upper arm, Whoop allows more flexibility, including wrist and body integration options. Neither has a display, and all data flows straight into a companion app.

Garmin’s Index Sleep Monitor also captures daytime heart rate, respiration, stress and calories burned. So in that sense, you can keep it strapped on 24/7. Which might surprise you considering the product is explicitly pitched as a sleep-only tracker. Body Battery updates too, which makes it useful even if you’re not pairing it with a Garmin watch during the day. Steps do not, which is surprising considering the device has an accelerometer inside.

Where the Garmin also falls short is during workouts. While the Index band continues to track heart rate during the day, it doesn’t log sessions or respond to high effort activity in any meaningful way. So even if your heart rate spikes, that data isn’t treated as exercise. You won’t get a workout file, strain score, or any credit toward metrics like Intensity Minutes or Training Status. If you want proper training data, you still need a full Garmin watch. Which kind of defeats the point of using the band on its own for daytime tracking.

The gaps that still make Whoop better for athletes

Not let’s take a closer look at its rival. As noted in our hands-on review, wearing Whoop feels like having a coach quietly observing you around the clock.

It’s not just the Recovery and Strain scores. It’s the way it rolls all its metrics into something that guides your day. Garmin has Training Readiness and Training Status. And sure, the Index Band feeds into these scores as far as sleep data in the morning. But for daytime updating of these metrics you need a proper Garmin watch.

That’s a big gap. It’s mostly to do with software, not hardware. Garmin already has the infrastructure to make this work. Right now, the Index Sleep Monitor can’t be set as your primary device in Garmin Connect, so it won’t trigger readiness scores or training insights without help. That’s a big missed opportunity if the aim was to create a true Whoop rival.

There’s also the matter of automatic exercise recognition. Whoop is excellent at identifying workouts passively, especially cardio efforts like running. The Index band doesn’t even try. Even if your heart rate stays elevated for an hour, it won’t mark that down as activity. The stress score just goes up.

Also, Whoop has one of the best smartphone apps out there. Things such as the journaling function and newly added features such as Healthspan add a lot of value. Improvements in Garmin Connect would not hurt.

Essential reading: Top fitness trackers and health gadgets

And let’s not forget the battery. With the Garmin, you’re looking at about a week before the Index band needs to be recharged. Whoop, on the other hand, comfortably hits 14 days. And it charges on-wrist using a clip-on battery pack. Garmin’s sleep band needs to come off and head to the charger.

Finally, it’s also worth mentioning the Whoop 5.0 MG. That one slaps on a few extras like ECG and blood pressure tracking, putting it further ahead in terms of health sensor depth. While those features won’t matter to everyone, they do show how far Whoop is pushing into more clinical-style monitoring, which Garmin hasn’t touched with this band.

What Garmin got right and where it can go from here

Despite its limits, the Index Sleep Monitor is better than expected. The data syncs reliably, the comfort is excellent, and for people who just want overnight metrics without wearing a watch, it nails the brief. Slap it on your upper arm in the evening, wear something else during the day.

However, if Garmin actually wants the Index band to go head-to-head with Whoop – it needs to loosen things up a bit. Let people make it their main device. Training Readiness should work without needing to power on a watch. Heart rate at high intensity exercise needs to be sampled more frequently. Step tracking wouldn’t hurt either, even if it’s just an option. And it really needs proper workout tracking, whether that’s with Connected GPS or something else. The hardware is mostly there.

Another option could be making this a dual-purpose device. Honestly, I feel they should have done this with the first-gen device. The band could have been designed to double as an upper-arm heart rate tracker. Garmin doesn’t have anything like that right now. It’s all chest straps for serious training. A band that handles both sleep and exercise could have slotted in nicely where there’s still a gap.

Garmin usually plays the long game. The Index Sleep Monitor feels like an early move, but it’s clear they’re paying attention to what Whoop is doing. And if they decide to go all in, they already have most of the tools to make it work. They also have a price advantage. The Index comes in at $149.99 with no monthly fees. Compare that to Whoop’s subscription model, and suddenly Garmin’s minimalist approach looks a lot more appealing.

Garmin Index Sleep Monitor vs Whoop 5.0: Tech specs comparison

Subscribe to our monthly newsletter! Check out our YouTube channel.