Revision as of 06:37, 29 November 2015

I've tested several optical heart rate monitors and found them rather ineffective, so I came to the Garmin 225 with low expectations. To my surprise, the 225 worked much better than the competition, though there are still compromises in the 225's optical HRM. I'm a little disappointed in the way Garmin has crippled the 225 software compared with the 620, and I'm looking forward to trying out the replacement 235. I would recommend not buying the 225 until the 235 is released and tested. I think the 235 will be a big improvement over the 225, with things like Connect IQ, but even if you decide the 225 is for you, the release of the 235 should drop the price of the 225. A simple rating of the Garmin 225 can be based on how well they can answer some basic questions:

• How far did I run? This is the most basic question, and the 225 has rather poor GPS accuracy, so its estimate of how far you've run needs to be treated with a quite a bit of caution.
• How fast am I running? Knowing how fast you're running can be a nice to know, or it can be vital for your training or race performance. Because of the nature of GPS, watches that rely on GPS signal alone tend to have serious problems with current pace. Without the ability to display current Pace From A Footpod while getting all other data from GPS, the 225 can't answer this question. The poor GPS accuracy exacerbates this issue, and I've seen the pace estimate wildly wrong on the 225. The 225 would be my top pick for marathon runners, but I firmly believe that this is a killer feature, as accurate pacing is essential for a good marathon performance. (I've some slight hope that Garmin will add this feature in with a firmware update, as they have to a number of their newer watches.)
• Where am I? The 225 has no navigation features. If you're lost, the 225 won't be much help.
• What's my cadence? Cadence is one of the most critical and often overlooked aspects of running. If you get your Cadence right, many other things naturally fall into place. There is support for Cadence from the internal accelerometer, though I find that's not as accurate as the Footpod which it supports.

The 225 is not a good choice for ultrarunners, as its battery life is too short. See Watches for Ultrarunning for more details. (Turning off the optical heart rate monitor only increases the battery life a couple of hours.)

The Garmin 225, showing the display of Heart Rate from its Optical Heart Rate Sensor.

1 Optical Heart Rate Monitoring

No one likes to wear a chest strap, and it can be particularly annoying for ladies as it can interfere with support clothing. This makes the idea of an optical heart rate monitor that uses the changes in capillary fill under the watch quite attractive, so I focused on this functionality.

• Optical HRM is never going to be as accurate as a chest strap. The chest strap measures the electrical impulses from the heart and can measure the time between each beat. This allows for analysis of Heart Rate Variability, which can provide some interesting insight, such as Training Effect. If you need that level of accuracy, optical HRM is not there and I doubt if it will ever get there. On the other hand, if you're after a good approximation of your heart rate, then optical holds more promise.
• One of the challenges for optical HRM is that movement can move the blood in the capillaries and make measurement tricky. I've found that the 225 works best with the strap tight; I have to tighten the strap two notches past where I'd normally consider the watch to be 'comfortably tight'. This tightness is enough that I can clearly see the imprint of the watch in my wrist when I take it off after a run. However, I have low body fat and skinny wrists (~9 inches/15cm), so those with a little more soft tissue might find it easier.
• Because blood flow to the skin is reduced when you're cold, I found it helped to keep my arms warm. In cold weather I used an arm warmer with the thumb hole placed so I could peak at the display. In really cold weather I'd normally wear my watch over the first layers of insulation, which obviously won't work with an optical HRM. This means the 225 will have to be covered most of the time in cold weather, which is annoying at best.
• The Garmin 225 will give a HR reading even if it can't get a reasonable signal. I'd much rather it gave a clear indication that it was having problems so I could adjust things. I generally know roughly what my HR should be for a given situation, so I can rapidly work out when it's confused, but you might find it harder.
• If you're still reading this, and you're okay with the compromises I've mentioned, then I found the 225 to do much better than the other optical HRM systems I've tried. I had remarkably few instances of the 225 reading wildly too high or too low. The graph below compares the 225 with two chest strap based systems.

I found it helped to keep the 225 warm for improved heart rate accuracy, but in colder conditions this becomes essential to prevent frostbite.

I had to have the Garmin 225 tight enough that it left a clear imprint when I took it off.

I'd rather the Garmin 225 said it couldn't find a Heart Rate rather than guessing. Here you can see it getting a Heart Rate from black cloth.

1.1 Heart Rate Comparison with Chest Straps

Comparison of the Garmin 225 with the Garmin Epix and the Suunto Ambit2.

The diagram above is a comparison of the Garmin 225 in red with the Garmin Epix in blue and the Suunto Ambit2 with the Polar H7 strap in green.

• The workout is a High Intensity Interval Training session, something that tends to highlight problems in Heart Rate monitoring due to the rapid changes in intensity. This is a WinTab workout, using 20 seconds all out, 10 seconds recovery, repeated eight times. (This is often confused with a Tabata workout, but a Tabata uses a specific intensity of 170% of the workload at V̇O₂max, not 'all out'.) The chart does not show the prior Warmup and short recovery time to rest the various monitors.
• The Wintab is from 1:00 to 5:00 on the chart, followed by a Cooldown from 5:00 to 14:00. There is then a gentle increase in intensity (going up a hill) from 14:00 to 16:00. After running as gently as possible from 16:00 to 19:00 there is a ~1 minute higher intensity period followed by a short walk to the end.
• The red arrow shows the rapid rise in heart rate from rest to maximum intensity. You can see that the 225 lags slightly behind the other two systems, but this is not excessive.
• The blue arrow highlights a slight drop in the HR reading from the 225. I've noticed this periodically, where the 225 becomes just slightly confused. One of the reasons I wore both a Garmin and Polar HRM is to verify that the fault lies with the 225, not the chest strap. These periods of confusion are generally fairly short and the different is not huge. In other optical systems, and with the 225 if it's not clamped down hard, they will often get wildly confused, reading wildly low (~90 instead of ~130), or wildly high (~170 instead of ~130).
• The green arrow shows another lag in response, and because the period of high intensity is so short, the 225 never reads the highest reading of that segment. If you relied on the 225, you'd see a heart rate of 10 beats lower than actually occurred.

Overall, I'm impressed with the Garmin 225's optical system, and I think it's well worth considering. You need to be prepared to live with the compromises, but for many, the chest strap has its own issues, including chaffing and the strange looks you sometimes get.

2 Garmin 225 Pros

• The Optical Heart Rate monitoring is more effective than other implementations I've tried. (See above for details.)
• The GPS accuracy of the 225 is reasonable. It's not as good as the Polar V800 or some of the other watches, but it's okay for most usage. Not surprisingly, the accuracy is about the same as the similar Garmin 620.
• The 225 is small and light, but the display is quite legible for its size. The display is color, but really this isn't much use on the 225. There is a display of HR with a color indicator of zone, but that's more of a novelty than a useful feature.
• The 225 will cache the locations of the GPS satellites for the next few days, makes for faster satellite lock. However, if you've not connected the 225 to the internet for a few days, the 225 can be painfully slow to acquire a lock.
• I like the small size of the 225, which feels more like a watch than a dive computer or 80's calculator watch.
• The 225 has some basic activity monitoring built in, which is not as good as the Basis Activity Tracker but it's nice to have.

3 Garmin 225 Cons

• A lot of the missing features from the Garmin 620 are from Garmin crippling the software rather than hardware limitations. I always like to see a company make the best product they can for a given price point, rather than using software crippling. Things like only displaying 3 data fields, or limiting the number of screens of data on the 225 is needlessly annoying. It's particularly bad when you want the optical heart rate monitoring, and can't get the advanced features on the 620.
• There is no way of displaying your current pace from the Footpod while using GPS for overall distance and course. While the 225 now has good GPS accuracy, it is not sufficient to give useful current pace information. For situations where pacing is critical, such as running a marathon, a Footpod works better. (Earlier versions of the firmware would always display the pace and distance from the Footpod when it's connected, but this was fixed in a recent update.)
• The 225 includes an internal accelerometer to give you an idea of pace and distance while running on a treadmill without a footpod, but I found it was too far out to be of any use. A lot will depend on your running style and how you use a treadmill.
• The battery life is short for ultramarathons, but it is fine for the most runners.

4 GPS Accuracy

The Garmin 225 does rather poorly for GPS accuracy, and rather worse than the similar Garmin 620. I was expecting it to be using the same chipset and antenna as the 620, which I would expect to give similar GPS performance. It's hard to be sure of the underlying chipset without disassembly, but the problem could also be due to a change in the antenna due to the extra optical HRM.

You can see the 225 has rather mediocre accuracy, and is rather worse than the similar Garmin 620. It does badly around the twisty section, cutting the corners too much due to smoothing. It does a little better with the sharp turn seen on the right side of the diagram. It gets a little lost going under the bridge on occasion, but that's not too much of an issue. The lap markers in blue are more widely dispersed than they would be with a better device. (This diagram has tracks color coded with green indicating good accuracy through to read indicating poor accuracy, and the lap markers as blue dots.)

This close up section of a zigzag shows the 225 tracking okay most of the time, but a disturbing number of the tracks are poor. (This diagram has tracks color coded with green indicating good accuracy through to read indicating poor accuracy, and the lap markers as blue dots.)

Here you can see the 225 displaying the typical GPS behavior with the tracks that have the green lines shifted slightly down and to the left, blue up and to the right. This is less marked that other devices, but you can see the pattern. You can also see the lap markers shifted based on direction. (This image has the tracks color-coded for direction, with green coming from the right, blue from the left.)

5 What's Missing

While I don't consider these missing features as 'cons', it's worth understanding the features that are missing compared with other watches.

• Altimeter. GPS is far less accurate vertically than horizontally, so a barometric altimeter can provide a much better idea of your ascent and descent. It can also be useful for navigation if you're ascending or descending a mountain. In some races I've been far more interested in how much ascent is left rather than the distance to the top.
• Navigation. The navigation capabilities are useful if there is a risk of getting lost. I've made good use of this feature when running in an unfamiliar city, or when running remote trails. (On a screen this small it might not be much use anyway.)
• Downloadable Apps. Smart watches have got is used to the idea of a device that can be extended with new functionality, and this concept is being introduced to running watches.
• Extended battery life. Some porches can extend the battery life by turning the GPS reception off for short periods. This can dramatically reduce GPS accuracy, but it's a useful trade-off for some ultramarathons.
• Graphs. Instead of simply displaying a numeric value for things like heart rate, some watches will display a graph of the value over time, giving you a sense of how things are progressing.
• Training Effect. The Firstbeat Training Effect gives you a sense of how hard each workout is, and this sometimes includes the time for recovery.
• Graphs. Instead of simply displaying a numeric value for things like heart rate, some watches will display a graph of the value over time, giving you a sense of how things are progressing.
• WiFi/Bluetooth Uploads. While the automatic upload of workouts via WiFi or Bluetooth to a Smartphone is nice, the upload will typically only go to the manufacturer's web site.
• Running Dynamics. Some of the newer Garmin watches can show and record Vertical Oscillation (VO) and Ground Contact Time (GCT).
• Alerts. Some watches will alert you when a metric is out of range. The alert for Cadence is really useful and one of my favorite features.
• Web Configuration. Some watches allow you to setup the configuration via a web site, and then download your changes. This is vastly easier than fiddling with the watch.

Please support this site This review was made possible by readers like you buying products via my links. I buy all the products I review through normal retail channels, which allows me to create unbiased reviews free from the influence of reciprocity, or the need to keep vendors happy. It also ensures I don't get "reviewer specials" that are better than the retail versions.

6 Visual Comparison

Garmin 225 top	Garmin 225 side	Garmin 620 top	Garmin 620 side
Suunto Ambit2 top	Suunto Ambit2 side	Suunto Ambit3 top	Suunto Ambit3 side
TomTom Cardio Runner top	TomTom Cardio Runner side	Garmin Epix top	Garmin Epix side
Garmin 920XT top	Garmin 920XT side	Leikr 1 top	Leikr 1 side
Polar V800 top	Polar V800 side

7 Comparison Table

I evaluate running watches in three distinct ways. Firstly, you can use a watch on its own, without any kind of Footpod. This is probably the most common way runners use their watch, but you miss out on a lot. The second rating is with a standard Footpod that is available quite cheaply. These Footpod's can be reasonably accurate once the calibrated, but calibration is a little tedious. The final evaluation is with the Stryd Footpod, which is vastly more accurate than any other type of Footpod, or and more accurate than GPS. The table below looks at the score, and the value for money of each watch for each of the three conditions. (I’ve also tested the Apple Watch 3, but I’ve not included it in these tables as it’s not really a running watch.)

The score is the sum of how well each watch can answer the four basic questions (how far, how fast, where are you, what's your cadence), plus some bonus points.

1. The "How far you've run" will be based on GPS only for "without Footpod" and "with Standard Footpod", but based on Stryd if supported in the "with Stryd Footpod" table..
2. How fast you're running assumes you're using a Footpod if it's supported, otherwise the rating is 0-2 based on GPS accuracy.
3. The "Where are you?" is based on various navigation features such as back to start, breadcrumbs, and preloaded maps. For some watches, you have to turn GPS off to get the benefit of Stryd, so those watches have worse "where are you scores" with Stryd than without.
4. The cadence score uses 1 point for an internal cadence sensor, 2 points for footpod support, 1 point for support from chest strap cadence, and 1 point for cadence alerts.
5. I give 1-2 bonus points for application support, 1-2 bonus points for data upload, 1-2 bonus points for Optical Heart Rate Monitoring, and 0-1 bonus points for battery life.
6. Value for money is the score divided by the price (at the time I last updated the table.) Your needs may be different, so you might weight the different aspects of the watches differently, or be basing your decision on different criteria totally. Hopefully this table will give you a good starting point for your decision.

7.1 Score Breakdown without a Footpod

7.2 Score Breakdown with a Standard Footpod

7.3 Score Breakdown with a Stryd Footpod

7.4 Basic Features

8 Navigation Features

For "navigation":

• Color Maps gives you full color maps, rather like a smart phone, with roads and paths marked out.
• Track Outline is a display of where you've run, rather like a breadcrumb trail. If there are maps, the outline is superimposed otherwise this is just the outline on its own without any context.
• Course Outline is an outline of a route that can be downloaded. I've found this useful during ultras or in unfamiliar cities where I've needed to know where to go.
• Back To Start is a simple arrow point to your starting point, so it won't help you backtrack.
• Back To Waypoint returns you to a previously marked location using a simple arrow to point.
• Compass. A magnetic compass can help you orient yourself or the map. Without a magnetic compass you have to be moving for the GPS to give you a sense of direction.

(Older Reviews: Polar RC3 GPS, Soleus 1.0, Motorola Motoactv.)