Coospo HW9 Review: An Affordable Heart Rate Monitor Wristband

Optical heart rate monitors are attracting more and more athletes by promising reliable heart rate measurement with greater comfort than a chest strap. The Coospo HW9 fits right in with this trend by offering a simple, comprehensive, and affordable solution. We tested it while cycling for several weeks to evaluate its accuracy, comfort, and ease of use.

By Guillaume Judas – Photos: ©3bikes.fr

A heart rate cuff serves the same purpose as a chest strap: it measures heartbeats and then transmits the data to a compatible device so it can be displayed during exercise or analyzed after the session. The difference lies in the technology used. Whereas a chest strap picks up the heart’s electrical signal, the Coospo HW9 uses an optical system similar to the one found in modern GPS watches from brands like Garmin, Suunto, or Coros.

The advantage of a dedicated armband is that it offers a more comfortable measurement location—on the arm or forearm—while potentially providing greater accuracy than a watch, whose sensor must account for wrist movements. For many athletes, this placement is also less restrictive than a chest strap, especially during long workouts. As for me, the Coospo HW9 is the very first heart rate armband I’ve tested, after more than 30 years of wearing a heart rate belt almost daily for my workouts.

Coospo is a Chinese brand that has made a name for itself over the past dozen years in the world of sports electronics, offering functional products at particularly competitive prices. We’ve already seen this firsthand recently with our review of the TR70 speed sensor, and we’ll be taking a closer look at this approach again soon with our evaluation of one of the brand’s power meters.

Coospo’s catalog features two main families of heart rate sensors: traditional chest straps and optical armbands, such as the HW9. According to retailers, this model retails for between approximately 32 and 65 euros and is available on platforms such as AliExpress and Amazon, as well as directly through the brand’s website.

Weighs just 21 g and offers about 30 hours of battery life

The Coospo HW9 weighs just 21 g, including the adjustable strap. The strap is easy to adjust, whether you choose to position the cuff on your bicep or on your forearm, just below the elbow. In fact, you don’t need to tighten it very much to ensure a secure fit.

When worn on the upper arm, under the jersey sleeve, the HW9 stays perfectly in place without causing any discomfort, and you’ll quickly forget it’s even there as the kilometers go by. This is one of the main advantages of this type of solution compared to a chest strap: superior comfort, especially during long rides.

Unlike some heart rate belts on the market, the HW9 doesn’t use a CR2032 or CR2025 button cell battery, but rather a rechargeable battery that charges via a magnetic cable. Coospo claims a battery life of 35 hours, but our real-world tests put it closer to 30 hours. As a precaution, I chose to do a quick recharge every week because, as with the TR70 radar we tested previously, the sensor doesn’t provide a particularly noticeable warning before the battery runs out.

One area in the Coospo ecosystem could be improved, however: despite several devices being compatible for the same sports use (speed sensor, heart rate monitor, power meter, GPS bike computer), each product still comes with its own charging cable. A more universal solution would significantly simplify day-to-day equipment management, especially for users with multiple accessories from the brand.

A handy LED display in certain situations

The HW9 is compatible with the CoospoRide app via Bluetooth on a smartphone, which allows you to manage the brand’s ecosystem and also to directly record your rides with your phone—much like a simplified GPS bike computer—with tracking of statistics and activity history.

From within the app, you can set up your heart rate profile, including your maximum heart rate and training zones. The HW9 then uses this information to provide visual feedback during your workout via an LED indicator whose color changes based on the intensity reached. The armband can also vibrate when the user approaches the red zone.

This feature may be useful for athletes who run or ride without a directly visible bike computer—for example, when wearing the armband on the forearm. However, in my case—with the HW9 placed on my upper arm under my jersey sleeve—the benefit is inevitably more limited, since the light indicator remains hidden during exercise.

Beyond the various color codes displayed by the LEDs, I appreciated the power button located directly on the sensor. This button not only makes it easy to turn the armband on and off, but also allows you to quickly check its status via a light indicator—a simple yet useful feature that helps prevent leaving the device on unnecessarily and conserves battery life.

Easy connection, but placement could be improved

Among the HW9’s strengths, its ease of connection is worth highlighting. I had no trouble pairing it with a Wahoo Elemnt Roam bike computer. Once the two devices were paired, the armband was automatically recognized at the start of every ride, without any disconnections or malfunctions. A major plus… provided, of course, that you haven’t forgotten to charge the battery!

As for the sensor’s placement, however, things turned out to be a bit less straightforward. I initially wore the HW9 on my left arm. Don’t ask me why—that’s just how I set it up initially, and for four runs, I didn’t bother to change it. Whether the sensor was facing toward the inside or outside of my arm, the data sometimes turned out to be unreliable, with a heart rate that was clearly too low at certain times and then abnormally high at others.

I also felt that these discrepancies were more pronounced during windy rides, especially when I was wearing a jersey with mesh sleeves. However, it’s impossible to say for certain that the wind was directly responsible: the tension of the armband, body type, blood flow, or even muscle movements can also affect the accuracy of measurements with an optical sensor.

I finally decided to wear the HW9 on my right arm. From that point on, there were no more issues: the data became perfectly consistent with how I felt and the intensity of my effort, with no dropouts or outliers, regardless of the conditions I encountered.

It’s well known that optical sensors built into GPS watches can sometimes lack accuracy when worn on the wrist, particularly due to wrist movement. With the HW9, however, once the right placement was found, the readings proved to be very consistent and perfectly usable for training.

Almost as accurate as a high-end chest strap

Finally, it’s time to compare the HW9 with two industry leaders: the Polar H10 and the Garmin HRM 200. Two chest straps whose accuracy I’ve already come to appreciate, but both of which have caused me a recurring problem for several years: skin irritation under the pectoral muscles. With the Garmin, the irritation appears on the sides, while with the Polar, it’s concentrated in the center of the chest.

I still can’t quite explain the cause of this irritation. Similarly, I’ve often noticed that some of my training partners regularly get inconsistent readings with these same belts, likely due to their body type, the shape of their ribcage, or characteristics specific to their skin. Chest straps remain the gold standard for accuracy, but they clearly aren’t suitable for all users.

With the Coospo HW9, worn on the arm, there’s no discomfort of this kind. On the contrary, comfort quickly became one of its main advantages… while finally allowing the skin on my chest to recover.

That leaves the key question: accuracy. By simultaneously comparing data from the HW9 and the Polar H10 on two separate heart rate monitors, the readings proved to be virtually identical once the intensity of the effort had stabilized. Discrepancies mainly occur during changes in pace. Like most optical sensors, the HW9 lags slightly—by about two to three seconds—both when the intensity increases and during recovery.

When comparing data from the HW9 and the Polar H10 simultaneously on two separate devices, the readings were virtually identical once the exercise intensity had stabilized.

In practice, this delay has no impact on endurance rides, tempo sessions, or threshold workouts. It will be more noticeable during very short intervals, where heart rate is, in any case, a secondary indicator compared to power, which remains the benchmark for guiding this type of training.

Finally, the HW9 proved to be unaffected by high temperatures or heavy sweating. Its waterproof design also allows for use in the rain, although this summer’s particularly dry conditions prevented me from testing this feature. However, the armband is not designed for use while swimming. Triathletes will therefore need to find another solution to measure their heart rate during the swim segment.

The Coospo HW9 has all the makings of a top-tier device

After several weeks of use, the Coospo HW9 leaves an excellent impression. Admittedly, it doesn’t quite measure up to a high-end chest strap when it comes to instantly tracking the most sudden changes in heart rate. But in the vast majority of situations, the data it provides is reliable, consistent, and perfectly usable for training.

Its main advantage, however, is its comfort. Lightweight, discreet, and easily forgotten once worn on the arm, it’s a genuine alternative for anyone who can no longer tolerate the discomfort of a chest strap—whether it’s skin irritation or a feeling of tightness.

I also appreciated how easy it is to use, the stable connection with the bike computer, its battery life—which is sufficient for several intense training sessions—and its rechargeable battery, which is much more practical in the long run than a button-cell battery system.

Priced between 30 and 60 euros depending on the retailer, the Coospo HW9 ultimately offers particularly good value for the money. For cyclists and athletes looking for a reliable way to measure their heart rate without investing in a much more expensive model, it’s a pleasant surprise and a credible alternative to the most well-known solutions on the market.

The COOSPO HW9 heart rate cuff at a glance… Pros: exceptional comfort, very reliable ANT+ / Bluetooth connection, very good accuracy during steady-state exercise, rechargeable battery, excellent value for the price Cons: slight delay in responding to rapid heart rate changes, placement may need adjustment depending on the user, battery alert isn’t sufficiently visible, proprietary charging cable Dimensions (L × W × H): 41.3 × 33.8 × 11 mm – Weight: 21 g – Battery: 90 mAh rechargeable lithium battery – Battery life: up to 35 hours – Wireless connections: Bluetooth 5.0, ANT+ – Heart rate variability (HRV): yes – LED indicator: yes – Charging method: magnetic via USB – Operating temperature: -10 °C to +50 °C – Price: approximately €30 to €60 – Contact: coospo.com

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