The Garmin Forerunner 405CX is at the very end of the spectrum, so I would say you should buy it only if you know you will really use an HRM, know that an HRM that connects to your phone isn’t good for what you need, and are sure you really need the Garmin’s built-in GPS and can’t go with the cheaper, less bulky FT60 because it doesn’t contain an HRM. If all of these are true, then sure – the Garmin is an excellent device for what it does, and provides a solid fitness tracking experience.

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Garmin Forerunner 405CX

Personal fitness tracking is a huge industry these days, and it really does work. Tracking your heart rate, speed, distance, and other vital metrics is a fantastic way to stay motivated, keep working out, and get to ever higher levels of performance, fitness, and wellness. After all, few things are more motivating than watching your own speed improve on tangible graphs and charts.

Today, I will be reviewing the Garmin Forerunner 405CX: a heart-rate monitor with a built-in GPS. The 405CX tracks your running or cycling in minute detail, then wirelessly connects to your computer and uploads your workout data to Garmin’s website, where you can peruse it at your leisure.

We bought this $270 Garmin Forerunner 405CX, so you can expect an honest, unbiased review. And of course, the cherry on top is that one lucky reader will win this review unit – participate in the giveaway at the end, and you too will have a chance to win it!

The Personal Fitness Monitoring Arena

garmin forerunner 405cx

To understand the Garmin Forerunner 405CX, or 405CX as I will be referring to it from now, we need to view it in the wider context of the personal fitness monitoring market. There’s a spectrum here: At the very first level, in terms of price, are smartphone apps like RunKeeper and Adidas miCoach. These apps do require a smartphone, but a smartphone is a versatile device which can be used for much more than just fitness tracking, and besides, you may already have one. These sit on the free to $10 range, and are a fantastic way to keep track of your fitness performance, as can be evidenced by their popularity. What these apps track essentially is time, distance, and speed, using your smartphone’s sensors (GPS and clock, really). Just knowing your elevation, path, and average pace, can make a huge difference in running and motivation – not to mention the social aspects of sharing exercise data and goals with friends.

Those who wish to give these apps a bit more oomph would need to move up into the next level in the spectrum: Accessories such as the $75 Zephyr HxM and $90 Polar WearLink+ Bluetooth transmitter. These are both heart-rate monitors which strap onto your body, wirelessly connect to your smartphone, and provide your fitness app with one more data stream – the all-important heart rate. In theory, with one of these, your smartphone is the ultimate fitness tracking instrument. But one problem remains: Checking how you’re doing mid-run. Pulling out your huge smartphone might be awkward, as will be running with it strapped to your wrist. You can always run with headphones and listen to audio cues, but not all apps have them, and they may not be as effective as just keeping an eye on your stats.

And this brings us to the next and final level in our spectrum: Full-blown personal heart rate monitors, such as the $210 Polar FT60 and the $270 Garmin Forerunner 405CX. These look like bulky wrist watches, but connect to a heart rate monitor and provide you with an ongoing data feed and training guidance which you can see at a glance mid-stride, without having to fumble with your phone. But if you already have a smartphone, should you really shell out $270 for the Garmin Forerunner 405CX? Let’s find out.

What’s In The Box?

garmin forerunner 405cx

The 405CX ships with an impressive bundle of accessories. In the middle column of this image, you can see the large plastic HRM (heart rate monitor) sensor strap, two alternative watch straps, the user’s manual, the charging dock, and the Garmin ANT+ wireless communicator (the bit that looks like a disk-on-key at the bottom). On the left, you can see included tools, as well as the international charger with its three interchangeable wall plugs. And last but not least, on the right is the CX450 itself – a rather bulky device.

Design and Aesthetics

garmin forerunner 405cx

The Garmin Forerunner 405CX is a bulky watch, even compared to the large FT60. Above you can see the men’s FT60 (left), the 405CX, and then a badly-scuffed ladies’ FT60. The FT60 doesn’t contain a built-in GPS, which explains why it’s so much smaller than the 405CX.

garmin forerunner 405cx

It’s also significantly thicker, as you can see above.

garmin forerunner 405cx

Unlike the FT60, the 405CX does not contain a user-replaceable battery. Instead, the battery is rechargeable via two tiny contacts, shown above, which the included charger clips onto. Another major difference is that the FT60 battery lasts up to a year of normal use, while the 405CX is rated for two weeks in power-save mode. That’s quite a difference, and again, it can be attributed to the 405CX’s built-in GPS and its sophisticated touch interface, which we’ll soon look at.

Another area in which the 405CX is noticeably bulkier is the HRM strap itself:

garmin forerunner 405cx

Below you can see a standard Polar WearLink strap (front) contrasted with the 405CX strap. The Polar strap is very thin and flexible, and its HRM sensor part clips on and off. With the Garmin, the sensor is built right into the strap, which is largely made of plastic and is much more massive.

garmin forerunner 405cx

Here, you can also see the WearLink sensor itself, which is noticeably smaller than the Garmin’s sensor part. The only advantage I could find for the Garmin’s strap is that you don’t need to wet it before using it: You simply strap it on, and it finds your pulse. With the Polar, you must put the strap under a cold water tap and then strap it on when it’s wet – not a fun way to start a training session, really.

Charging The Garmin Forerunner 405CX

garmin forerunner 405cx review

The 405CX ships with a proprietary charger clip which looks a bit like a pulse oximeter (you know, the ones they strap onto your finger at the hospital). At its other end is a USB cable which you plug into the charger, and then you just latch the clip onto the watch so that its two tiny “teeth” bite into the contacts on the back of the watch:

garmin forerunner 405cx review

A full charge takes around 2-3 hours.

The Touch Interface

garmin forerunner 405cx review

Above you can see me configuring the watch – I am not just holding it by the bezel. The bezel itself is touch-sensitive, even though it is made of plastic. In fact, it is even multi-touch: Touch it with two fingers, and the 405CX’s blue backlight turns on. The touch interface sounds great on paper, but was really quite annoying to use. You scroll through menus by running your finger around the bezel and confirm by tapping the bezel once, but many of my gestures were not correctly identified. While the interface doesn’t work well for lengthy configuration sessions, it is well-suited for use while running, when you don’t have time to fumble with the buttons.

Training With The Garmin Forerunner 405CX

garmin forerunner 405cx review

To test the 405CX, I strapped it on and took it for a light stroll. Once outside, I had to pause for a moment while the watch got its bearings and tracked down enough GPS satellites. This took less than a minute, and was illustrated with a simple progress bar. I then started walking (I didn’t actually run this time), and walked for a few minutes before realizing I never actually linked the 405CX with the HRM strap. I paused, navigated the menus for a few moments, and that was it: The watch identified the HRM and instantly connected, and heart rate data started transferring. That’s when I took the picture you see above.

garmin forerunner 405cx review

One of the ways the 405CX tries to motivate you is by providing you with a virtual workout buddy you can jog with. Here you see that I’m lagging behind my imaginary friend by a whopping 23:53 minutes – it went running ahead and didn’t stop to see why I’m not moving. That’s what you get for having imaginary friends, I guess.

garmin forerunner 405cx review

As you train, you can touch each of the bezel’s four main areas (top, bottom, left, right) to get information about different aspects of the session. Touching the bezel’s left side, for example, pops open the GPS menu. Using this menu you can verify that the GPS is indeed on, and monitor your current accuracy. This is a very cool display, and the Garmin had absolutely no trouble tracking me down to five meters, even though I was walking in narrow streets surrounded by tall buildings.

garmin forerunner 405cx review

The 405CX features several training-mode displays, and they are fully customizable.You can have up to 3 personal screens, and get to decide how many metrics (1-3) to show on each screen, as well as what those metrics would be. To me, this shows Garmin really gets that the primary reason to use a watch HRM these days is to see data at a glance. By providing absolute customization, Garmin guarantees that you will have the exact display that’s useful for your training style. This is one of the most impressive parts of the 405CX experience.

Computer Connectivity

garmin forerunner 405cx review

Once you are done with your training session, it is time to upload your data to the Web and see how you did. This is done using the included USB ANT Stick: You set up Garmin’s software, plug in the stick, and it then recognizes the watch is nearby and asks to pair with it:

garmin forerunner 405cx review

Once you confirm, it asks for your free Garmin Connect account credentials so it knows where to upload your training data:

garmin forerunner 405cx review

It then crunches along for a few moments, transferring data. This was pretty slow: Transferring just a single session took around four minutes.

garmin forerunner 405cx review

Once that’s done, you can log on to Garmin Connect and see your session:

garmin forerunner 405cx review

And of course, drill into the session for the nitty gritty details:

garmin forerunner 405cx review

There is also a map (minimized above for obvious reasons). I compared the 405CX’s built-in GPS to my Galaxy S II GPS by tracking the same session with RunKeeper, and the maps came out basically identical, so GPS tracking is at least as good as on the Galaxy S II (which means it is very good). You also get a nice summary of your session, as well as time and elevation charts.

Should You Buy The Garmin Forerunner 405CX?

This time, there is no simple answer to this question. If you are just starting out with personal fitness monitoring, then probably not. Try out a few of the free and inexpensive apps and see how it goes first. The Garmin Forerunner 405CX is at the very end of the spectrum, so I would say you should buy it only if you know you will really use an HRM, know that an HRM that connects to your phone isn’t good for what you need, and are sure you really need the Garmin’s built-in GPS and can’t go with the cheaper, less bulky FT60 because it doesn’t contain an HRM. If all of these are true, then sure – the Garmin is an excellent device for what it does, and provides a solid fitness tracking experience.

As with most MakeUseOf reviews, we're giving this review unit away to one lucky reader.

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