I have been using the Garmin Forerunner 405CX GPS-enabled sportswatch and heart rate monitor for about a month and a half now, so I thought it’s time to post a review. I got it mainly for running, and I think that it is essential gear for runners, but I’ve also used it on hill walks and just casual walks — although I only wear the heart rate monitor when running. I’ve covered almost 300km and climbed nearly 12km in just under 60 hours of activity time with the device, so I’ve got a pretty good idea about it. It also comes with advanced calorie calculation based on heart rate, gender, age, weight and activity level. It’s impossible to determine how accurate the calorie calculation is, but it claims that I’ve used about 17,600 calories in the mentioned activities. The device retails for about £235 with the heart rate monitor at Amazon, although I managed to get mine for a bit less.

You can see the link above for detailed specifications, but here is a list of the most important features:

• Measures distance, time, laps, elevation gain, heart rate, calorie usage and pace/speed
• Four customisable data screens with up to three elements, including a virtual training partner
• Stores all data in internal memory and uploads it wirelessly to you PC or Mac
• Comes with the Garmin Training Center software where you can view previous activities and design workouts etc.
• Garmin Connect online Training Center for sharing and comparing your data
• There are some built-in workouts such as heart rate zone training and interval training, which are fully customisable
• Alerts for heart rate, pace, reaching goal etc.
• Bike mount and foot pod (for indoors training) available as optional accessories

Garmin Forerunner 405CX

The device is very easy to set up and using it is straight forward. The wrist band is customisable, but I haven’t tried to do anything to it. Although the watch is not very bulky, the rigid part is fairly long, which can be a bit of an issue in terms of having it in a comfortable position. I prefer to wear it over my shirt, but that only works if you’ve got long sleeves, which will not be an option when it gets warmer. Still, it’s not too uncomfortable. The heart rate monitor, which you strap around your chest, is surprisingly comfortable; most of the time I don’t even remember it’s there.

The user interface is fairly intuitive, with a bezel system not unlike the one familiar from iPods; you slide your finger around the bezel to change options, and tap it to confirm. It has a major advantage compared to the iPod wheel though: it works even when you’re wearing gloves. The menu system is simple and works, although some options are quite deep in the menu.

My personal experiences from using the device have been very positive. It’s very useful to know the exact distance you’ve covered as well as the time of course. The best thing is being able to keep track of your pace though: you can get this as a simple km/h input, average lap pace, current lap pace, average pace for the whole run, and so on. The distance of a lap is customisable, but the default is one kilometer. Incidentally, you can get everything in miles as well if you prefer. Anyway, whenever you complete a lap, the device beeps (but you can disable this) and gives you the lap time. This is extremely useful for pacing yourself and seeing the effect of hills and such on your pace.

Then there’s the heart rate monitor. The first few times that I used the device, I quickly discovered that I was running much too fast, that is, my average heart rate was too high (well over 160bpm). When you upload your data to the Garmin Training Center, you get a graph of your pace and heart rate. You have to set up the device so that the heart rate zones apply to you — you can do this by entering your age, gender, and maximum heart rate — but after that you get a good idea of the level of exertion for your activity. There’s a lot of research about heart rate zones and the guidance varies a bit, but basically you can divide it into five zones: Zone 1 being 50-60% of your max. heart rate, Zone 2 is 60-70% … and Zone 5 is 90-100%. The vast majority of your training should be somewhere around Zone 3. So, like I said, I discovered that I had been running way too fast, namely in Zone 4. So one of the first things I did was to try to pace myself and stay mostly in Zone 3. After only a couple of weeks of doing this, I was able to cover my normal 10k route in the same time or a bit faster than previously while staying within Zone 3. So that was a major improvement strictly due to the use of a heart rate monitor.

I should say something about the GPS itself. It appears that the distance is measured very accurately, as far as I can tell, but the same is certainly not true of the elevation gain. Also, you can’t access data about total elevation gain during the activity; this is possible only after uploading the data to your computer. Now, the data for elevation gain seems rather unreliable because my normal 10k route has varied between something like 400-600m, while it should be pretty much the same each time. This doesn’t make much of a difference for running, but for hill walking it would be nice to see the accurate elevation gain. Having said that, when the elevation gain is steady, as it tends to be when climbing a mountain, the accuracy seems to improve. I’ve also checked the reported elevation while up on a mountain against the map value, and it seems to be accurate within 5 meters or so. Anyway, the best way to do this would be to include a separate barometric sensor for elevation gain. Unforunately this unit doesn’t come with one of those. Incidentally, there is a separate menu in the device for GPS accuracy, you can also check how many satellites it can find. A final issue concerning accuracy: the maximum speed sometimes goes haywire. So, when you upload your data, you might find that you managed to run at a pace of 18,000km/h for a fraction of a second, which sounds rather unlikely. Something of the sort has happened to me a couple of times.

Garmin Forerunner 405CX

The accuracy issues are not very serious, but there is one clear flaw: battery life. When not in use, the device remains on standby for a good few weeks, and Garmin promises 8 hours in training mode. I’ve gotten close to this, but the unit has died on me after 6 hours. This is not an issue for running of course — unless you’re doing two marathons back to back — but hill walks could easily take longer than that. The device isn’t designed for that of course, but I’d like to be able to use it for that as well. Not to mention that you’re out of luck if you hope to use the device for several days without having the opportunity to recharge it. Recharging itself is simple and quick though: it only takes an hour or so from empty to full battery.

Finally, a few words about the Garmin Connect online Training Center. I find it to be one of the best features. Not only does it give you some more accurate information than the Training Center Software, such as good map/satellite/terrain/Google Earth view of your route, it also works as an online library of all your activities, which all get a permanent link. This makes it very easy to share data with people you might have been running/hiking with, or anyone else for that matter. If you’re interested, you can find a full database of my activities with the device at my Garmin Connect page. This gets automatically updated whenever I have completed an activity and bring my Garmin device within the range of the wireless USB receiver connected to my PC. So you can spy all my running/hiking routes from here! Well, I might regret advertising this if I start seeing creepy people lurking behind trees on my runs…

Let’s end the review with a summary of the positives and negatives of the unit:

Positives:

• Accurate data on distance/pace
• Built-in workouts
• Indispensable data on heart rate and exertion levels
• Easy data synchronisation with your computer
• Garmin Connect online for sharing your data

Negatives:

• Short battery life in training mode
• Inaccurate for measuring elevation gain
• Occasional glitches in max. speed

In my opinion, the positives far outweigh the negatives and I have certainly not regretted buying this device. It has completely changed my training. I had been thinking about running a half-marathon some time this year, I’ve never done one before. However, I’ve been running distances up to 20k in training now without any trouble, and I’m starting to feel that a half-marathon is not such a big deal. I’d be happy to run one, but there aren’t any organised races near me and it feels a bit silly to go somewhere just to run a half-marathon. Consequently, I’m now considering of doing a full marathon instead. I’ve got my eyes on the Helsinki City Marathon, which takes place on August 14th this year. Still plenty of time before that, but I’ll probably do it if I’m in Finland then and manage to keep training.