SHOWDOWN: Whoop vs Polar Loop vs Amazfit Helio Strap

Tags: Fight | Polar | Amazfit | Smart

14.12.2025 | 14 MIN

In the world of wearables that track our bodies 24/7, choosing the right (or “best”) option is becoming a challenge. In this showdown, Whoop, Polar Loop, and Amazfit Helio Strap go head-to-head. Each band has its strengths and weaknesses — the goal is to see who each one is for and how they differ.

In this triple face-off, I’ll compare design, sensors, battery life, sports and lifestyle features. I’ll wrap up with my verdict — the winner and recommendations for different types of users.

13.12.2025
Polar Loop unveiled – Polar now has its own Whoop

Design – just a piece of metal/plastic on a strap

I don’t want to downplay design too much, but this type of device is meant to be discreet, so it makes perfect sense that the design is as simple as possible.

Whoop

The newer Whoop 5.0 measures 34.7 × 24 × 10.6 mm, weighs around 26.5 g (depending on strap type), is IP68-rated, and is water-resistant to real-world depths of up to 10 meters.

Given the price, Whoop is probably my biggest design disappointment. It’s the most expensive of these devices, requires a subscription, and at that price I expect it to feel and look the part. Unfortunately, it didn’t give me that feeling.

The strap looks nice, but once I handled it, it felt rather cheap. And I think the same about the module and the flip clasp. The module is plastic — that’s fine — but the flip clasp felt very tinny and didn’t give me the sense that I’d paid a hefty chunk of money for it.

Polar Loop

Polar Loop is, in my view, the most refined of the bunch, even though it’s the largest of the three. It measures 42 × 27 × 9 mm, but you won’t really notice it on the wrist. The construction combines stainless steel and a polymer body, which is also why the Loop is the heaviest — it weighs 29 grams with the strap.

Water resistance is listed as 30 meters, which can be a bit confusing compared to Whoop, which should handle a real 10 meters of depth. By contrast, the Loop only allows light water activities — swimming or showering is fine. I wouldn’t go diving for shells with it, though.

Of all contenders here, Polar Loop feels the most premium — though “premium” may be a strong word in this context. Let’s say it feels the most solid. You can really tell at a glance.

Amazfit Helio Strap

Amazfit Helio Strap feels like a mix of Whoop and Loop (which the name slightly hints at). Unlike both, however, it’s lighter — it weighs just 20 grams. Its dimensions are 33.97 × 24.3 × 10.59 mm, so a tad smaller than Whoop. The case is plastic, with a nylon hook-and-loop strap attached.

Water resistance also sits between the two — Helio Strap offers 5 ATM and is suitable only for swimming and showering.

Helio Strap is indisputably the lightest of all and you really forget you’re wearing it. It’s a silent, almost invisible presence on your wrist. Unfortunately, light doesn’t mean most comfortable here. The weight is great, but the strap honestly didn’t suit me at all. The nylon edges felt rather sharp and kept cutting into my skin. If Helio Strap weighed a few grams more, I’m afraid it would be unbearable. That said, it uses Quick Release, so you can swap it for something more comfortable.

Who wins on design?

For me: Polar Loop, for several reasons. I don’t mind that it’s a little heavier. On the contrary, it feels more premium. And it really looks premium, not just on the wrist. The metal and polymer case combo looks nice, and the strap itself is well-finished and comfortable.

Sensors – the big omission is GPS

First, here’s why none of these devices has GPS, so I don’t have to repeat it for each model. The concept is primarily lifestyle. They’re meant to diligently track your lifestyle and recovery — and bother you as little as possible. That’s why these devices are tiny, and there likely wouldn’t be room for a GPS receiver anyway. The main reason, though, is that GPS doesn’t fit the concept. You can do basic sports with the bands, because they have the relevant sensors. For outdoor activities, you’ll need to use your phone’s GPS.

15.6.2021
Heart rate sensor – everything about it and how can it help you

Whoop

Whoop focuses less on classic sports tracking and more on deeper biological metrics. It tracks your heart rate 24/7, heart rate variability, respiratory rate, skin temperature, and blood oxygen saturation — all handled by an optical sensor.

Whoop 5.0 also adds ECG in the MG model, plus improved algorithms for sleep and HRV analysis.

The most crucial sensor here is certainly the optical one, but for better motion tracking it’s aided by an accelerometer and a gyroscope. In terms of sensor accuracy, Whoop sits around the industry baseline.

Polar Loop

Polar Loop has an optical sensor with Precision Prime technology that continuously tracks your heart rate. It’s complemented by an accelerometer. It should also include a thermometer, but it’s not available to users yet. Polar is likely still testing it and will enable skin temperature via a future update.

31.5.2021
ALL ABOUT: Pulse oximeter – Why is it important, and what does it tell us? (1/2)

Polar offers a solid core set of sensors, but it lacks a gyroscope — and that thermometer isn’t available yet. In terms of accuracy, Polar unfortunately trails Whoop, which is a mild disappointment in my eyes.

Amazfit Helio Strap

Amazfit is the cheapest, but it didn’t skimp on sensors. It offers the reliable BioTracker 6.0 sensor you’ll also find in Amazfit’s pricier watches, such as the T-Rex 3 Pro.

It can continuously measure heart rate, blood oxygen, breathing rate, and heart rate variability. The sensor is further complemented by an accelerometer, gyroscope, and thermometer.

So while Helio Strap doesn’t stand out by the number of sensors, it’s excellent given the price.

What matters most to me is accuracy — and Helio Strap performed the best in this matchup.

Who wins on sensors?

Amazfit Helio Strap. Surprised? It sealed the win multiple times. It delivers some of the highest accuracy in this contest and, on top of that, it’s the cheapest while still covering the key sensors. Whoop isn’t the most accurate sensor-wise, and I honestly have no idea what went wrong with the Loop, which also didn’t measure as expected.

Battery life

Whoop

Whoop 5.0 claims up to 14 days of battery life on a single charge — and in practice it sticks to that figure. What I consider a big Whoop advantage is the PowerPack. If you have one, you don’t have to take Whoop off at all to charge it. PowerPack is essentially a mini power bank that clips onto the top of the band and charges it without taking it off your wrist.

Whoop PowerPack

It’s great. You don’t have to fuss over when and how to recharge. You just grab the PowerPack and snap it on the band when needed. It’s handy for travel, too. Primarily, though, it prevents you from ever taking Whoop off and ensures consistently recorded data.

Polar Loop

Polar claims up to 8 days on a single charge. That’s a fairly acceptable result. I expected less in practice, but I was pleasantly surprised. I got as much as a lovely 10 days several times, and I didn’t baby it.

Helio Strap

Amazfit Helio Strap quotes around 10 days, which sits between the Loop and Whoop. Of the three, Helio Strap shows the most noticeable drop when you enable everything to the max. At full tilt, battery life drops by about 30% to around 7–8 days.

Who wins on battery life?

Whoop 5.0 — it really has the longest endurance, and the PowerPack option is more than practical.

Sports features – they can do some, but they aren’t sports watches

You may have noticed this already in the sensor section. We’re missing the key GPS sensor, so we can’t talk about a pure sports device. All three handle basic tracking and even have automatic activity detection and recognition. Still, during training we usually want real-time data. We want to know how fast we’re running or riding, and how far we’ve gone — without having a phone in hand with the app open.

Whoop

Whoop doesn’t primarily focus on tracking sports performance (e.g., speed, distance) — it has no GPS, doesn’t measure pace or route. Its strength is the Strain metric (overall body load), recovery analysis, and recommendations on when to train and when to rest.

Whoop can detect various activities automatically, but for details (distance, pace) you need a phone connection. It’s ideal for athletes or enthusiasts who aren’t obsessed with training data, or for those who want to optimize recovery, load, and sleep patterns — complementing the functionality of their sports watch.

Polar Loop

Polar Loop supports automatic activity recognition thanks to the accelerometer and optical heart-rate sensor. Within the Polar ecosystem, it offers more advanced metrics like Training Load, Fitness Test and more to help assess training load and performance level.

Fitness Test is something I like about Polar. It’s a five-minute fitness test you can perform even while lying down to estimate your VO₂Max without extra equipment. The automatic calculation considers your resting heart rate, HRV, and your physiological data such as sex, age, height, weight, and training level.

8.4.2021
What is VO2 max?

It’s a pity Polar didn’t add more of the many other tests it offers in its watches. It would have elevated the Loop’s functionality. It’s clear, though, why Polar didn’t — the Loop’s sensor suite required for those tests doesn’t match.

Of course, the Loop can also automatically detect sports activity. If you’re as skeptical as I am, you can start it manually in the app.

Amazfit Helio Strap

Helio Strap combines wellness and sports features. It can track training load, training status, PAI, and other metrics that combine activity and recovery.

Helio can do automatic detection too, but it’s not entirely reliable. It either detects activity with a delay or ends it prematurely when your heart rate drops significantly. That’s honestly pretty frustrating. For strength training, longer rests are normal and it makes sense for heart rate to drop. As a result, my workout was split into several segments many times, which is a pain for analysis. This could be fixed easily by having the app first ask whether the workout is finished.

Who wins on sports features?

It’s tight here. But within what each device can do:

• Polar Loop: good integration with Polar’s ecosystem, simple sports, a solid choice
• Helio Strap: thanks to the option to connect as an external sensor to other devices, it has an advantage when combined with another device
• Whoop: strong at managing load and optimizing recovery, slightly trails in detailed training data, but it can also pair as an external heart-rate sensor

For me: Whoop has a slight edge thanks to its ability to act as an external sensor and its stronger emphasis on recovery.

Lifestyle features – made for this

The purpose of these devices is fairly straightforward — to improve your lifestyle. In practice, it’s not that simple. Most of us have some bad habits, and we also live in a fairly hectic time that doesn’t help.

The main job of these bands is to show how we’re doing in this regard and, above all, to help improve and structure our lifestyle. Whether it’s stress management, a regular bedtime, or anything else — all of these steps can move us forward and improve how our body functions.

Whoop

Whoop is great in many respects — you might be as charmed as my colleague Dominik by the Health Span feature. Put simply, it tells you whether your body is aging slower, faster, or in line with your real age. To bring it closer, I’ll borrow Dominik’s own words:

Sleeping too little? Whack — a few years up. Not enough time in zones 1–3? Whack. Not enough in zones 4–5? Whack. Low VO₂ Max? High resting heart rate? Not enough strength sessions? Inconsistent sleep times? Whack. Whack. Whack. Whack! And suddenly at 27 you’re almost 80, there’s a photographer standing over you to shoot you for a cigarette pack with the warning “Smoking kills,” and you’re wondering why you didn’t get Whoop sooner.

We all probably know deep down that exercise, regular sleep, and avoiding smoking or alcohol do our bodies a world of good. But until we see it visualized somewhere, we might not give it the weight it deserves. And that’s where Whoop shines. It not only quietly observes us — it tries to teach us about our habits and, if they’re bad, help us get rid of them.

By observing, I mean 24/7 health monitoring (heart rate, HRV, respiratory rate), sleep analysis, daily load recommendations, etc.

Overall, I see Whoop as the most advanced lifestyle band out there. Its features and metrics are well thought out, it sums everything up nicely, and perhaps that’s why you see it on the wrists of the biggest sports icons like Cristiano Ronaldo, LeBron James, and many others.

Polar Loop

Polar didn’t invent anything new — it simply implemented features it has long used in its watches. That’s not a complaint, because these are great features like Nightly Recharge, SleepWise, etc., designed to help users understand how their body functions overall.

Nightly Recharge monitors sleep quality along with heart rate, HRV, and respiration to calculate your overnight recovery and then gives recommendations on how to better handle stress or approach training.

The Loop also tracks sleep and its stages well and has SleepWise, which, based on sleep analysis, provides information on daytime alertness and how and when you’ll be focused during the day.

Helio Strap

Helio Strap likewise offers all-day tracking of your being — heart rate, stress, sleep, skin temperature, blood oxygen saturation, etc. That gives you a comprehensive picture of health and recovery.

It’s worth mentioning BioCharge, which simply evaluates your body’s energy. Poor sleep, high stress, or high training load? Your value may drop — and vice versa. Of course, it’s always best to listen to your body, but if BioCharge is low and you’re not feeling great either, it’s not a bad idea to heed it. It basically serves as a readiness indicator.

Who wins on lifestyle features?

Whoop 5.0 thanks to its focus on long-term metrics (recovery, sleep) and overall data treatment. Amazfit Helio Strap is close behind, and Polar Loop is the least comprehensive of the three for me.

The app – where everything gets decided

Don’t get it? Let me explain. Bands like Whoop, Loop, and Helio have no display and no buttons — nothing you can control directly on the device. That’s why the app, its capabilities, and its polish are absolutely key to how good the band is. Without the app, these devices would be useless, so app quality matters more than you might think.

Whoop

It has the most polished app — not just in terms of design, but in the breadth of data it explains with the help of artificial intelligence that walks you through everything. Not clear on something, want details or a recommendation? Just ask the AI and it will explain everything thoroughly.

Polar Loop

It pains me to say this, but Polar pretty much killed the overall quality and essence of this band with its app. I’ve felt something similar for a while about using Polar Flow with their watches, too.

I hope no one gets too mad when I say their app is one of the worst. I know a few people who swear by it, but they seem to be the exception.

My issue is the lack of clarity. I don’t see any intuitive logic. Things you’d look for under tab A are under tab X. The overview isn’t particularly dazzling either. Which is a shame, because Polar’s data analysis itself is very good.

Where Polar generally fell behind is AI integration. Polar apparently isn’t working with it (yet), which is a huge shame — and they’ve fallen behind. I find Polar Loop very appealing, but because of the app it’s largely unusable for me.

Helio Strap

Amazfit is a different story! Polar could take a textbook lesson here. Not that long ago, Amazfit’s app was merely average — it did the job but wouldn’t blow you away. Today? One of the best apps out there. It’s clearly structured, with help from AI. There’s also Zepp Coach support that can advise you on training.

I don’t have much to add. Amazfit is living proof you don’t have to pay a ton of money and still won’t miss out.

Who wins the app category?

The winner is Whoop, whose app is genuinely excellent. Amazfit is hot on its heels.

Subscription

Price may or may not be crucial, but I believe most of us look at it. Whoop is the most expensive and doesn’t come with a one-off price. If you want to tap the device’s full potential, its price tag climbs to as much as €400 per year. And it repeats every year.

Polar Loop is officially the only one that doesn’t require a subscription. You pay a one-off amount of around €160 and you’re set until the band dies. It’s a nice thought that you save a bit, but what you save in your account you may lose in nerves. At least that was my case. A poor app, no AI-based insights... Yes, you save money — but at what cost.

Saving the best for last? To me, yes. Helio Strap comes out at a little over €80. That’s a truly affordable price. Yes, it can get pricier if you opt for a Zepp app subscription, but it’s not necessary to get the most out of the device. And if you do go the subscription route, it won’t cost anywhere near Whoop’s pricing.

Who wins on cost?

My pick is Helio Strap. Given the price, it’s incredible what it offers. Second would be Polar Loop, which has plenty of shortcomings, but in combination with its price and build I like it. If I weren’t a reviewer, I honestly wouldn’t pay that kind of money for Whoop.

So which one should you pick?

I’ll first frame it from different angles, because different factors can decide and we all look at this a bit differently.

• Polar Loop: build and material quality are crucial to me, and looks take precedence over features
• Helio Strap: I want the best value for the lowest price possible
• Whoop: I care about in-depth analysis of all data

This showdown deserves a clear verdict. Personally, I wish someone would combine these bands into one excellent device. But for now, that perfect combo exists only in my imagination. Since that hasn’t happened yet, my choice would be the Amazfit Helio Strap.

Helio Strap is the cheapest — that alone could be enough to pick it. But it offers much more. It’s equipped with a strong set of sensors led by the BioTracker 6.0 heart-rate sensor. It has proven its quality for quite some time and, in my opinion, it’s dependable. I also mentioned the app — again, Amazfit’s is fantastic. Perhaps the best of all wearable makers right now. It has detailed, clear analysis, AI integration, and a polished design.

I can’t skip the fact Helio Strap can function as an external sensor and you can connect it to other devices. On top of that, Amazfit also offers a smart ring and, of course, watches. You can build a pretty cohesive ecosystem that works together seamlessly. And what’s more, it doesn’t have to cost more than €400 — which is, for example, Whoop’s price for a year.

• official Whoop photos
• official Amazfit photos
• official Polar photos
• screenshots from the Whoop, Zepp, and Polar Flow apps