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I've tested several optical heart rate monitors and found them rather ineffective, so I came to the [[File:Garmin 225-top.JPG|thumb|right|300px|The {{Garmin 225}} with low expectations, showing the display of Heart Rate from its Optical Heart Rate Sensor. To my surprise, ]]The big difference between the 225 worked much better than and the competition, though there are still compromises in [[Garmin 620]] is the 225addition of [[Optical Heart Rate Monitoring]] (OHRM). I's optical HRMve found that OHRM is not ready for real world usage. I'm also a little disappointed in the way Garmin has crippled the 225 's software compared with the 620, and I'm looking forward to trying out the replacement 235. The older 225 doesn't have Garmin''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 s [[Connect IQ]], but even if you decide the 225 which is for youanother significant shortcoming, the release of the 235 and I'd argue it should drop the price be a major factor in your choice of the 225watches.''' A simple rating of the Garmin 225 can be based on how well they can answer some For a more fundamental look, there are four basic questions:* '''How far did I run?''' This is the most basic question, and the 225 has somewhat reasonable, but not great rather poor GPS accuracy, so its estimate of how far you've run needs to be treated with a little 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 mediocre 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.)

The 225 is not a good choice for ultrarunners, as its battery life is too short. See [[ShoesBest Running Watch#Watches for Ultrarunning| Watches for Ultrarunning]] for more details. (Turning off the optical heart rate monitor only increases the battery life a couple of hours.)[[File:Garmin 225-top.JPG|thumb|none|200px|The {{Garmin 225}}, showing the display of Heart Rate from its Optical Heart Rate Sensor.]]=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 [[FirstbeatBuyAmazon| 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. {| classAZID="wikitable" B00XKRWTUE|- valignAZN="top"|[[File:Garmin 225 Warmth.jpg|none|thumb|x200px|I found it helped to keep the 225 warm for improved heart rate accuracy, but in colder conditions this becomes essential to prevent frostbite.]]|[[File:Garmin 225 Imprint.jpg|none|thumb|x200px|I had to have the Garmin 225 tight enough that it left a clear imprint when I took it off.]]|[[File:Garmin 225 Confused.jpg|none|thumb|x200px|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.]] |}==Heart Rate Comparison with Chest Straps==[[File:Garmin225 Comparison.jpg|none|thumb|500px|Comparison of the Garmin 225 with the [[Garmin Epix]] and the [[Suunto Ambit 2]].]]The diagram above is a comparison of the Garmin 225 in red with the [[Garmin Epix]] in blue and the [[Suunto Ambit 2]] 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 [[VO2max|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. }