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Polar RCX5 Review


  • Excellent battery life
  • Waterproof
  • Post-workout analysis


  • Lack of built-in GPS
  • Ugly design
  • Difficult to adjust

Key Specifications

  • Review Price: £329.50
  • Multiple sport profiles
  • Heart rate monitor training
  • Customisable display
  • Long battery life

We continually check thousands of prices to show you the best deals. If you buy a product through our site we will earn a small commission from the retailer – a sort of automated referral fee – but our reviewers are always kept separate from this process. You can read more about how we make money in our Ethics Policy.
The Polar RCX5 is not just a mere watch. It calls itself a “fitness computer” and it lives up to its name by analysing your statistics on the move to help you get the most out of your fitness sessions. It all starts by monitoring one particular marvel of technology – your heart.

If you work at 50-60 per cent capacity you improve overall health and recovery rate. At 60-80 per cent you’ll improve endurance. Go even further and you’ll develop performance and speed. And the RCX5 can help keep you in the right zone while you’re working out.

You can throw more data at your fitness programme by adding a stride sensor, which measures your speed and pace as well as your average length of footfalls. Once we calibrated the unit over half a mile, we found it was fairly accurate when matched against a GPS unit. A 5.7 mile run was recorded as 5.8 using only the stride sensor.

That’s less than a 2 per cent variance, and we tried to throw it off by changing our gait and putting in the occasional sprint, yet the sensor could judge not only the average length of our stride at 3ft 5in, but the type of step we were taking, be it a light walk or a heavy run.

However, the sensor itself is twice the size of the Nike Sportwatch monitor which can fit into the sole of a compatible running shoe and tested extremely well in the tunnels during our test at the Paris Marathon.

The RCX5 is the lowest profile fitness watch of the five sport watches we have tested this year (See our Fitness Technology Round-up for full details), sitting at just 1.1cm high on the wrist. While fully integrated with GPS, the flag ship Garmin Forerunner 610 towers above the RCX5 and yet has a smaller screen.

Measuring 24.5 x 4.6 x 1.1 cm and weighing 46g, the RCX5 is also 33g lighter than the Foreunner 610 and 22g lighter than a Casio G-Shock Classic. We weren’t keen on the design, though. While we can forgive the manufacturer’s name being on the watch face, but manufacturers take note: unless you have made a car, don’t emblazon the model number all over your product. The watch has the word “Polar” written in no fewer than six places, and  the words “Performance Science” written on the face and down the side of the strap, which is frankly rediculous.

The 1.2 x 1in screen is easy to read and the buttons are well placed and big enough to be operated wearing gloves while staying out of the way during exercise. We especially liked the big red timing/record button which is on the face of the watch, ready to punch when you stop or start a workout.

The display can show up to six different screens that the user can scroll between during a workout. Each of these is customisable with everything from a live readout of calories burned (based on the user’s heart rate and weight), to average cadence if you’re working on building speed, pace, miles covered or more.

There is also a heart-tap function, which can display a data set of your choosing when you bring the watch up to the heart rate monitor. Like the best innovations, this is something we didn’t realise we wanted until it was invented for us. Having the ability to check the time of day during a run simply by lifting the watch to chest height made us wonder how we managed without it.

Which brings us on to our biggest and perhaps most contentious point. While it won’t deter every athlete, the biggest shortcoming of the RCX5 for us was the lack of built-in GPS. We understand this makes the watch lighter and slimmer for the times when you might not want to use GPS, for instance if you are swimming or on a treadmill, but we prefer the more integral approach.

Unlike running with the Nike Sportwatch and the Garmin Forerunners models, RCX5 owners who want to track their route have to carry the G5 GPS sensor as an extra accessory. This can be worn on an armband, or we found it worked equally well in a rucksack on a hip belt.

If you will always want to track your run on a map after a workout, this feels like extra equipment to have to carry, especially if you run with a phone or an MP3 player on your arm already.

What we can’t complain about is the RCX5 ‘s efficacy as a training tool. Using the included heart rate monitor, we were able to focus on keeping our heart rate under 160 beats per minute to run below 80 per cent of our capacity. This allowed us to run further without burning out and we set a personal best for a half marathon, something we had never managed when training with a standard GPS watch. Measuring speed alone regardless of heart rate ignores the fact that running up a hill at a consistent speed is tiring and will wear you out sooner over a longer distance, whereas running at a constant capacity is running smarter.

On the plus side, the absence of a GPS unit means regular runners don’t have to charge their watch at the mains every week. The standalone G5 GPS Sensor charges via micro-USB and the battery lasts 20 hours, but the S3 Stride Sensor and the RCX5 watch itself take a CR2032 battery which lasts between 8 and 11 months.

With just the basics or all this kit combined, you’re all set to train and upload your workouts to the Polar Personal Trainer website and view or share your cadence, heart rate and a wealth of information.

Uploading to the site is easier than any sport watch we have used. The USB stick recognised the watch and started uploading new data straight away and was free from the software install errors and aborted uploads we have experienced with the Garmin models, and free from the USB connectivity issues of the Nike Sportwatch.

Once you’re logged in, there is a focus on training as well as analysis and you can set yourself goals as part of a fitness regime.

As you can see from one of our test runs, there are plenty of statistics and you can share your individual runs with your friends via email or social networking sites including Facebook and Twitter.

We were disappointed at not being able to zoom in to the extent you can on the Garmin service, so we couldn’t conduct our customary “wiggle test” in which we strafe down a street from side to site in order to test the accuracy of the GPS tracking. On a monitor set at 1920×1200, we could zoom into the Garmin Connect so the span of the screen covered 55m of road. On the Polar site, the maximum width covered a wider area of 2.3 miles across, which didn’t provide much detail although it was fine for a overview of the route.

We found a slight GPS variance between the Garmin Forerunner and the Polar G5 unit on longer runs. Tested over a half marathon, the RCX5 gifted us an advantage over the distance, which the Polar product said we ran 35 seconds faster than its rival at 1:54:20, although it’s hard to say which one was right. We’d like to think it was the faster time, and as flattery will get you everywhere, we’re happy to further sing the praises of the Polar, which handles mutli-sport training better than any of its rivals.

Cyclists can add a cycling cadence sensor
to their cyberman training get-up. Perhaps more importantly to some, the watch, stride sensor and the heart rate
monitor are waterproof to 30 metres, something only the bulky Garmin 310 can
claim in the Forerunner range, making them perfect for triathletes.

The RCX5 also does a great job of reporting your data via the watch itself,
allowing you to view at a phenomenal amount of information about each session
on the dispay without having to upload your stats and visit the website to
analyse your workout.

We were less impressed with the price, at £323 for the GPS model, and at an
extra £109 for the S3 stride sensor, you’ll be shedding the pounds in more ways
than one.

Other packages breakdown as follows:

  • Polar RCX5 with Heart Rate Monitor – £267.50
  • RCX5 Run, which includes the above plus the S3 stride sensor £329.50
  • Polar RCX5 BIKE includes CS speed sensor, HRM and bike mount £296.37


  • G5 GPS sensor £ 110.46
  • S3 stride sensor £109


The RCX5 is a training watch with a difference. While it doesn’t have
built-in GPS, it is thinner and easier to use than many of its rivals, it’s
waterproof and it records vast amounts of data in a way which is easy to
interpret. It’s not perhaps the best all in one solution if you’re just into getting out and about and tracking where you’ve been but if you really want to improve your fitness, the Polar RCX5
means business.

We continually check thousands of prices to show you the best deals. If you buy a product through our site we will earn a small commission from the retailer – a sort of automated referral fee – but our reviewers are always kept separate from this process. You can read more about how we make money in our Ethics Policy.

Trusted Score

Score in detail

  • Usability 9
  • Features 6
  • Value 6
  • Design 7

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