COROS APEX Pro | Full review and performance test

The APEX Pro is the latest model of the Chinese/American brand COROS. And maybe you ask yourself... who is COROS? It is a brand with very few years in the market but it has had an exponential growth. Maybe not at a sales level (at least not in Europe), but certainly in terms of product range.

Their first watch is only two years old, the COROS PACE, a basic triathlon watch very similar to the Garmin Forerunner 735XT (practically a copy in terms of aesthetics), but in these few years they have had time to bring out three other watches on the market: the APEX, the VERTIX and the APEX Pro which is the one that occupies this review.

Both APEX and VERTIX take a lot of influence from the Fenix series of Garmin (especially VERTIX). At first this influence was such that they looked more like a "knockoff" of any Garmin model than a product of their own.

Luckily this has been changing and COROS is finding its own identity. The APEX Pro is the perfect mix between the original APEX and the VERTIX, and the novelties that are coming to the watches through constant firmware updates are making COROS be seen less and less as a Garmin copy.

Features such as the track mode or the COROS POD that offers not only running power but also different running metrics have been some of its latest updates.

At the moment I don't think there is any brand that is more watched over by the big manufacturers than COROS. They are starting to have an interesting range, they have a lot of money behind them (proof of this is the number of sportsmen they sponsor) and above all they aspire to grow in the market.

The evolution has been very fast in a very short time. Do the big dogs in the industry have a reason to be scared? Well, that's what I'm going to try to show you in this analysis.

To do this review, COROS has provided me with a unit of the APEX Pro with the COROS POD. As I always like to clarify, my intention is that once the analysis is completed it will be sent back unless the brand considers it interesting to keep the watch here to test future updates (sending it back and forth to China is not cheap).

I want this to be clear because there is no compensation of any kind from COROS, the test is totally independent. The reviews I publish are always written with the maximum objectivity and in the most impartial way possible. 

If you like this review and find it useful in deciding to buy your next GPS watch, please use the links on this page (well, you can buy that GPS watch you want or anything else, anything goes). You won't pay more than it's worth, but the seller returns a small percentage which helps to cover the cost of hosting the site and, obviously, my work. Or you can become a VIP member..

I'm not going to take any more time, as the presentation of the review is already being much longer than usual, so let's see if the latest model of COROS, the APEX Pro, turns out to be such an interesting model.

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A quick view of the COROS APEX Pro

If there's something I like about testing new watches, it's that everything is new, which means that not only do I have to know it in detail, but also that explaining it to you has a little more stimulus than not telling you about the umpteenth Garmin watch where almost everything works the same.

The COROS APEX Pro, like the VERTIX, has three control buttons (one of them with a rotating crown) and a limited use touch screen.

The control of the watch and all its functions is primarily through the buttons and the crown, which is to be appreciated. However, the touch screen can be used for certain functions, such as scrolling in widgets, data pages, or navigation map.

The crown is what differentiates the control of the COROS interface from any other model on the market (except the Apple Watch). It is the main control method and I won't deny that it doesn't take some getting used to. 

Moving through the menu, widgets, etc., is all done by turning the crown. As well as unlocking the watch both on the main screen and while you're training, the lower button allows you to return to the previous menu and mark laps, while the upper button only serves to turn on the light. 

Holding the bottom button also gives access to a quick menu, both during and outside of training.

The optical heart rate sensor is the same as in the VERTIX, with a specific sensor for pulse oximetry (SpO2). We can make a reading at any time through the quick menu.

But its main utility is from 2,500m altitude (which will be measured thanks to the barometric altimeter it integrates), in which it will show a small graph at the top of the screen to have a reference of whether the value is good or dangerous. Being at sea level it's hard to find a mountain over 2,500m high to test it, so I'll have to trust that COROS has already done it.

Unlike Garmin, COROS does not store the records it takes over time, so it's not possible to see a graph with the trend it has been taking over time (something that is very useful when making high mountain ascents).

What there are charts of is heart rate, altitude, air pressure and temperature. For all this there are widgets on the watch, which are joined by one with the summary of the day's activity (calories, training time, steps and ascended floors) and another with the mobile phone notifications.

Within widgets with graphics we can scroll horizontally to see a data in time. Simply press the crown and then scroll it by turning it or using the touch screen.

COROS allows you to choose from a number of watch faces. The options expand over time, but we cannot create one of our own or install other third-party developer options.

What we can do is, once the dial is selected in the application, change the color of the accents through the menu.

The phone app is what we use to synchronize all the data, being the only place where we go to be able to find all our data since there is no web platform.

And of course the rest of the functions like uploading routes, configuring notifications, sending training sessions automatically to external platforms, etc.

These are the basic usage aspects, but let's see what the sports aspects are.

Use of COROS APEX Pro in sport

But let's go with the part that will interest you the most about the COROS APEX Pro, which is its behavior when it comes to playing sports. That and no other is the reason to buy this watch.

Currently these are the sport profiles supported by the watch, being remarkable that COROS has recently updated the list adding the snow ones just before the arrival of winter:

Each of these sports can be configured independently, and it is necessary to do so through the mobile app, since the settings you can make on the watch are quite limited.

You have five data screens that you can configure and, in each of them, you can show between 2 and 4 data. The data selection is the typical and usual one with instantaneous data, averages, altitude and accumulated altitude difference, etc. 

There are some special things like power and running efficiency, ratio and stride height, etc (the same as in the advanced Garmin metrics), but for that you need to be training with the COROS POD.In cycling you can have instant and average power of 3s, 10s and 30s; as well as normalized power (NP), but not intensity factor or other more advanced and licensed metrics from another platform (TrainingPeaks).

On the watch we can simply configure different alerts (pace, distance, cadence, FC), auto pause or metronome.

We can also create very basic interval workouts (far from what Garmin or Polar allows us). You can select an interval distance or time, number of repeats and allow warm up and cooling, but you won't be able to select a target.

Once everything is set up, the main screen of the sport profile will show you the status of the sensors before starting training. Here you can see heart rate, battery remaining, GPS coverage and other sensors like the COROS POD.

As for sensors, the watch is compatible with ANT+ and Bluetooth (the latter option has been added in the latest firmware version). You can use either of these two standards to connect heart rate, speed, cadence or power sensors.

While you are training you can switch screens using the crown or the touch screen itself, if you have enabled it. However, after a while the watch locks and you will have to unlock it to do any operation, which is somewhat uncomfortable because it takes a little more time. Unlocking it is easy because you simply have to turn the crown, but if you're running at a high pace it can be a little tricky.

Once unlocked, besides switching between the different screens you have configured you can pause the activity by pressing the crown (and you will have a menu where you can end the activity or consult the details or the laps you have marked) or mark a lap using the lower button.

Leaving the lower button pressed accesses the same quick menu of the watch mode. The upper button simply turns the screen light on or off, although the APEX Pro also responds to wrist gestures.

Once the training is completed you can review all the data directly on the watch screen.

And of course also in the app, after synching the watch.

We can configure automatic export to other platforms, such as Strava, TrainingPeaks, etc.

And we can also export the file manually, in the different types of files most used.

From all the specifications of the COROS APEX Pro (and in fact of practically any COROS watch), if there is one thing I can highlight it is the battery life: it is brutal. These are the official numbers:

• Up to 40 hours in GPS mode
• Up to 100 hours in low-power UltraMax GPS mode (with lower GPS accuracy)
• A maximum of 30 days without using GPS. When using GPS the total battery life will obviously be reduced. 

Is this data real? I can't tell you if those 40 hours are really 40 or if it stays at 38, but I can confirm that the battery life is very, very good. I can say without fear of being wrong that in the time I've been testing the watch I've charged the watch every 10 or 12 days, with a GPS use of around one hour almost every day. 

No other watch I have used so far has been able to even come close to the eternal battery sensation of the COROS. Not even the latest models of the brands that use Sony's GPS chip (the same one used by the COROS). Something is being done to achieve this enormous battery life, and they are certainly doing it very well.

COROS Track run mode

One of the latest updates to COROS has been to include a specific mode for running on track and field. It is a different sport profile from the running one, it is located in the profile menu under the name "Track running".

This is the mode you should use when you go running to a track, because the watch will be able to perfectly identify the lane you are running in, making the layout and measurement exclusively for that lane.

In this mode the watch uses GPS data and through an algorithm it will place us correctly on the 400m track providing not only a nice track, but also accurate data on pace and distance, 

But first we need to tell the watch which lane we are going to run on.

The fact of selecting a lane at the start of the training does not force you to run on that lane all the time, you can pause the activity at any time and in the pause menu you can switch to another lane.

The mode is smart in the sense that 1TP10we start running off the track and the recording is done normally, i.e. 1TP10we run from home to the running track, and that part will be recorded as any training on the street. But from the first turn on the track the clock will correctly identify that you are already on the 400m track (and will warn you with an indication on the screen). And when we leave the track, for example to go home in the cold, it will again record normally.

How does it work in reality? Don't worry because of course I've tested it too.

I went to the track when I had to do long interval training. I had to do 6×1,200m, making the first and last 400m of each series stronger. And I did it in the following way:

• Warm up on lane 3 for 4 turns (the lane is 415m, therefore 1660m)
• 3 series of 1,200m on lane 3 (the lane is 415m, total 3,735m)
• 3 series of 1.200m on lane 1 (the lane is 400m, total 3.600m)
• Cooling down in lane 6 during 2 turns (the lane is 438m, total 876m)

The total would be 9,871m, but after each series of 1,200m there were 2 minutes of rest in which I walked a little on the track so these distances would also have to be added up. The total distance recorded from the three watches I wore were these:

• COROS APEX Pro: 10.180m 
• Garmin Forerunner 945: 10,270m
• Suunto 7: 11.020m

The total distance of laps would be 9,871m, considering that I'm always doing the rope correctly, which I'm not, so there's also a few meters of slippage...

In principle a fact that could perfectly match the total distance, since there are 309 meters left that I can have traveled perfectly on every break between intervals.

But the best thing comes when you check the track.

Take that!

Here are my passes for each of the lanes.

And in satellite view, the track is shifted one lane to the right of what should be the correct lane. Here, half a meter can be missing in the initial location of the COROS and another half meter in the Google mapping if it is not perfectly aligned (which can also happen - and does happen).

But let's compare it to what I got from the other two watches...

Completely different, right?

It is a very interesting mode that works reasonably well, but there is still room for improvement and I would like for example that the watch does automatic laps of 400m showing directly on the screen times without having to set the autolap or marking the manual lap.

Or that when synchronizing the activity it automatically identifies when we have started the interval and when we have stopped to give the complete data of each series, for example identifying intervals of 1600m and showing it directly in the summary (something similar to what is done in swimming).

In addition, that in the middle of the activity could show remaining lap distance and real pace adjusting to the position of the track and calculating time and distance, instead of continuing to rely solely on GPS. It is a good start that with two or three brain storming sessions 1TP10 could be much more interesting.

Route navigation

Route navigation is another possibility that has been added to the COROS watches through successive updates. 

To use the navigation you will have to obviously add a route first. COROS does not have any route creation system, so we will have to rely on any other utility that creates a route in .gpx format, be it Strava or Wikiloc or whatever.

Once you have the file you can send it to your phone in the way you prefer (email, file, etc.). This will mainly depend on which platform you're on -iOS or Android-. Once you've added the route to the app, you'll be able to sync it to your watch.

And with the route on the watch, you can select it in the activity settings.

In the watch we have access to the same elevation data that we have seen from the mobile app, both during the activity and before starting it.

The navigation is simple, the screen simply shows the route we have loaded (of course without maps of any kind), and we will only receive a warning if we go off the marked path.

You can zoom in using the crown (50km to 25m), and scroll along the route using the touch screen. 

In short, a very simple navigation that will meet the basics, but not much more.

Running power and advanced metrics

One of the novelties of COROS is the possibility of measuring running power. But the watch does not do it directly (as the Polar Vantage V), but it needs an external accessory called a COROS Pod.

It is composed of a series of accelerometers that identify the different movements of the body, also giving information of more running metrics:

• Stride length
• Ground contact time
• Left/right balance
• Vertical oscillation
• Stride ratio (ratio between stride length and vertical oscillation)

Then we have the running efficiency, a representation of how your running efficiency is. To calculate it, we take into account the pace and the W/kg. The efficiency will be good when at a high pace the power/kg is low.

According to COROS, an average runner usually has a running efficiency of between 90 and 110. Above that figure are the elite runners, below it indicates that the technique needs to be worked on.

That is, in my case it indicates to me that my racing technique is deplorable, which is probably not far from reality, but I will talk about these data later because they have to be taken with a grain of salt.

Finally, there is the analysis of the running power. When running we can identify three movements: horizontal, vertical and lateral.

• The percentage of horizontal power is the amount of energy we use to move our body forward. The higher this percentage is the better our technique, because it means we are not wasting energy on superfluous movements. Obviously it would be impossible to reach 100%, we will always spend some energy on vertical movement because when we stride we always go up and down.
• The percentage of vertical power is the amount of energy we spend on the movement of the stride itself. An elite runner will have a low percentage, that's what we see in African marathon runners, the feeling that they are floating is due to a very controlled vertical movement.
• Finally, the percentage of lateral power is the energy that we spend doing waist movements or similar. There will always be some energy spent on this because of bracing, but it should not be high.

As I said at the beginning, to have this data you need an external accessory, the watch is not able to display it without the COROS Pod because it needs those external accelerometers.

The power and efficiency data are obtained through the brand's own algorithms, let's see if these data are useful or not.

Data that do not add up to the COROS APEX Pro

However in the COROS APEX Pro (and by extension the rest of the brand's models) there are things that are not well thought out, all of them around the training load and running power measurement metrics.

All these metrics and algorithms are not outsourced to third party companies as is the case with Garmin (which licenses almost all of FirstBeat) or Suunto. Like Polar, all the metrics they use are developed in-house.

This shouldn't be an issue, in fact in the case of Polar it isn't. But of course, Polar has been in the industry for many years and is precisely one of its strongest points, the amount of science behind all its metrics.

COROS has just arrived on the market with a dazzling escalation of products, but we don't know anything about what's behind it or what all its metrics are based on or what it has been compared or studied against.

The thing is that when one stops to look closely at any of these data immediately raises alarms. The first thing that strikes me is the estimated threshold pace, COROS puts it at 3'57".

The threshold pace is one that we can endure without accumulating lactic acid in the blood and, therefore, the pace at which we could run without accumulating excessive fatigue. Theoretically this threshold rate should be reached at heart rate of the lactate threshold, which the app has set at 167ppm.

For a standard runner, the threshold pace and lactate threshold usually coincide with the pace at which 1TP10We could do a 10K. While the 167ppm you indicate does seem to me to be an accurate figure, in my wildest dreams that figure does not equate to a pace of 3'57". For an elite it would be even lower. 

Where does it come from? Simply from the VO2max tables, but it is not taking into account values such as age, weight, height, etc. If I were a 20-year-old kid in competition weight, with the VO2max that has marked me it would be feasible, but not right now, just not. In the end it is simply repeating very generic data that we can obtain from any VO2max calculator online.

There are more data that appear in that table that do not fit me, for example the rest heart rate. Usually my minimum heart rate is around 44-45 ppm, and yet in RHR it is set at 56. But entering the heart rate section the last record contradicts the data that COROS sets in the app.

Then we have the training load, which is a metric that in the case of COROS is totally volatile. According to COROS, I can do a slightly strong training on January 25th that puts the load at a little over 80, but two days later I have already lost all the training load?

The training load should be a metric that descends more slowly. It's as if two days after running a marathon tells us that we are fully recovered. 

In the picture above the last peak corresponds to a hill training of which I still have my legs a little tired. According to that graph today I could go out to do intervals, but I tell you that is not the case.

As for the training level metric I don't have much to say, because it is a COROS-specific data that has no equivalence on any other platform. For COROS it is an equation that takes into account the VO2Max, lactate threshold and training efficiency that simply assesses what range we are in.

These data should be there to add up, not to create confusion, and if they are not well developed I prefer them not to show up because they certainly don't help the way they are now.

Let's dive into running power. As I've always said, the first and most important thing to take into account is that it is an estimation and it is not the same as cycling power that can be measured directly by the deformation of the component where the gauge is.

In running, the manufacturers make the calculation using algorithms, taking into account various data such as pace, weight, altitude variation, ground contact time, etc. At the moment we do not have access to a data that is real, so we only depend on this estimate.

Once we know that the measurement is not real we enter other values such as considering if it's useful. The second aspect to consider is that it is not possible to compare the data neither between manufacturers, nor between users of the same device. Therefore I do not expect that the power measured by Stryd is exactly the same as that measured by Garmin or Polar, but I do expect that when one goes up the others do it in a similar measurement. That is to say, that it is comparable.

That's something I checked back in the Polar Vantage V review, comparing it to the Garmin and Stryd measurement.

As you can see, the data is different, but the trends are very similar. When the power increases, it does so in all three charts and all three charts are quite stable. Well, this same test in the case of the COROS is a disaster because the power varies so much.

The graph from Stryd is the purple, and you can see that it is quite constant. I have also included the wind incidence graph, to confirm that the wind strength has not been the problem of the different measurement.

Here is a picture of the heart rate graph, so you can see that the workout is indeed quite balanced in terms of effort.

But the key is that in this training I was specifically looking for hills to corroborate what I had already been seeing in different trainings. Here you can see the altitude graph.

The algorithm that COROS is using is simply poorly developed. Let's take it one step at a time.

The section of point 1 everything seems to work quite well. Here I'm running around 4:45min/km on the flat, and in both cases it detects when I stop for a moment to cross a street. I reach the first ascent (marked by 2), and despite maintaining a constant effort the power that COROS record falls by about 100W. It is as if it hasn't identified that I am climbing a hill.

Just as point 2 ends and before point 3, there is a sudden spike in power. If you compare it with the altitude graph above, you will see that at that point there is a drop. But the biggest thing comes at point 3, where the COROS records two huge peaks, even up to about 850W of power GOING DOWN. 

According to COROS, it is much more difficult for me to go down a slope than to go up one. Point 4 is very similar, the COROS is detecting a rise in power when it is a constant intensity. More notable is point 5, at the end of that training I am running very smoothly.

Where is the issue? That COROS is simply associating power to the running pace, if it is high COROS thinks it is because I have accelerated, if it is low, because I have relaxed, all this regardless of whether I am going up or down hills. And if there is an aspect where power becomes important it is precisely in training or races with constant changes in elevation.

Training on the flat does not present these problems, let's take this intervals on the track for example.

In this case we do see a power that, although it differs in value, is comparable between the different series. We do have one graph that is parallel to the other and we can see that it is correlative with respect to the training carried out.

But if running power is the basis for all other efficiency metrics or power analysis... it leaves me with very little confidence to believe in that data.

GPS Performance

Like the optical heart rate tests you'll see in the next section, the GPS comparisons are done in the same way: with the watches accompanying me in my regular workouts, wearing both the COROS APEX Pro and other models, and checking where problems occur.

I do not have any defined path to establish a score for the simple reason that there are other external factors that we should never forget. Things like clouds, leaves on the trees or simply the position of the satellite can alter the GPS results from one day to the next.

This is why I prefer to make this type of comparison instead of having a predefined route and assess it from this one.

This is one of the routes that I usually do and that normally is not excessively complicated, but on this day it seems that there were strange things... Already from the beginning you can see that there is an area with important problems, and an area at the beginning where there is a small discrepancy. 

For this test, in addition to the COROS, I wore the Apple Watch Series 5 and the Garmin Venu.

I'll start with that first point I've marked. Here the one that makes the mistake is the COROS APEX Pro, because it's far from the real track. I'm not used to running in the middle of the highway. Both the Garmin Venu and the Apple Watch are more or less accurate at this point, although the latter due to the filtering of its register ends up eating all the turns.

Many changes of direction in the image below. There is a river crossing by a bridge, where the COROS arrives already badly placed. The descent by that street towards the beach is correct in the three clocks, but in the turn to cross the river again the COROS moves quite a bit from the real route (the same as a little further on, both highlighted in the image).

I have highlighted a point that must be done as the Garmin Venu has done. You must save an area of stairs, so on the way back (the track parallel to the river), when you reach the end of the street you must turn right, go two meters and then turn left, that is, exactly what you see in the graph of the Garmin.

However, that turn hasn't existed for either the Apple Watch or the COROS, which have simply made the turn directly and haven't had time to appreciate that rapid change of direction. They have completely filtered out the turn and eaten it up.

I now come to the very erratic area that I had highlighted in the first image. This is always a complicated point because the area in which you run is a row of trees that is surrounded by trees on both sides of the running area.

It is common to find problems here, as well as a somewhat erratic measurement of rhythm, but that day was a real disaster on all three clocks, probably because the day was so overcast.

At least the COROS has behaved more or less correctly on the way back (the one way was frankly bad, going over all the buildings). The way has done it by the right point, infinitely better than the Garmin Venu.

However, the pivot point, which I do in a totally open area (where the start and finish of the Marbella Ironman), does not present so much of a problem for any of them despite how complicated the day was in general.

We are on a different day and in a different area of the coast, in this case it is a path by the sea that, depending on the area, has enough coverage by the trees that does not facilitate signal reception.

This is the beginning of the activity. Again we can see that the COROS sins of rounding slightly in the turns. It is not an excessive cut, but it is present and we do not see it in the other two graphs of the Garmin Forerunner 945 and Polar Vantage M.

Further on there is a really complicated area. In the lower part of the image - which corresponds to the going of the training - you will see that there are several changes of direction. These changes are real and they are produced by dodging the crowd that at that time was along the promenade, so there is nothing to object to any of the clocks.

The turn is on the other side of the building (next to the main avenue), and just below a very tall building and sometimes under it. This causes all three clocks to be lost (especially the Garmin). In this case it is the Vantage M that recovers fastest, followed by the COROS which, without doing as well, does perform better than the Garmin.

This other area is very complicated: a very narrow path under quite leafy trees that leads to a sharp turn. Here the COROS behaves correctly again; again better than the Garmin which, without making it very disastrous, performs worse than the APEX Pro.

This is as far as running is concerned, in cycling as usual there is no problem of any kind, both because of the amplitude that usually receives the GPS signal and because of the speed itself, as we move faster there are fewer problems of correct triangulation.

You can see this image as an example of a bike ride where only one track can be seen because the three are totally overlapped. 

Even by zooming in, it is not possible to find a point where a clock contradicts the Garmin Edge 1030 (or go off the road).

Overall the performance of the COROS APEX Pro has been remarkable. 8 out of 10. That means it has not been perfect (because none of them will be), but the result I have obtained in different terrains has been more than enough to say that podria use the watch perfectly in any training I can think of.

And all this without forgetting the fantastic battery life offered by the COROS, something in which, believe me, it stands out above the rest.

Optical heart rate sensor

The COROS APEX Pro has the same optical pulse sensor as the COROS VERTIX, which includes SpO2 estimation to estimate oxygen saturation.

At the moment in both COROS watches it is only used to estimate blood oxygenation at altitude (useful for those who move in the mountains), but unlike other brands such as Garmin, it is not used for sleep analysis.

As far as the sensor behaviour is concerned, I found lights and shadows. Anyway, it is worth remembering that it is always possible to pair an external sensor for the most complicated activities (intervals, series and cycling), and that the APEX Pro is compatible with ANT+ and Bluetooth sensors.

Before I show you comparisons of different sensors, I would like to remind you of some basic aspects of optical sensors.

Keep in mind that a wrist heart rate monitor does not work the same way on all bodies. We're all different, and if we put things in the equation like skin tone, tattoos, body hair... the difference from person to person can be quite big.

In my tests it is not that the spectrum of users is very broad: it is me, myself and I. So what works well for me might not do it for someone else, or it might be better.

But the most important thing to keep in mind is that you have to follow some guidelines to wear the sensor. It should be tight (but not cut off your circulation), enough to keep the watch from moving freely on your wrist, leaving a separation of approximately one finger from the wrist bone. By following these details you will ensure that you get the best results that your conditions can offer.

During the several weeks that I have been testing the APEX Pro I have had the opportunity to record many trainings, from which I have selected the following. 

I start with an easy training, constant rhythm for about 10 kilometers and without being too demanding. Besides the COROS, I carry on the other wrist the Garmin Venu and a sensor Polar OH1+ recording data in its memory.

This is the simplest test you can take with an optical sensor, and in this case at least you've passed it. There is no discrepancy beyond the first few moments of training, which is common until the body reaches temperature (and the veins dilate). In fact during those moments it is also common to find problems with the pectoral pulse sensors.

Another similar training, but increasing the pace progressively. In this case the test is against the optical sensor of the Apple Watch Series 5 and an HRM-Tri sensor paired with the Garmin FR945.

Same sensations, except at the beginning there is only one point where the COROS graph is separated from the other two.

You see that although it may seem a lot, when you zoom in and select that area you see that there is no more than two or three keystrokes difference.

Let's move on to series training. In this case the Polar Vantage M is paired with a Polar H10 sensor, while the APEX Pro and Forerunner 945 are using the optical pulse sensor.

There are some moments when the FR945 has slight peaks, but in general it has been a good performance given the difficulties that usually arise in this type of training.

Finally we have a cycling training. Warm up, six series in uphill and downhill. You can see in the graph that in this case the other devices are the Garmin Venu and the HRM-Tri which this time is connected to the Garmin Edge 1030.

Let's change things up, we go with an interval training but now riding on the bike. The other optical sensor I carry for testing is the COROS APEX Pro watch, while the Garmin Edge 1030 is using Garmin's HRM-Tri data.

There are three clearly differentiated parts: the first one where I go to the area where I do the series, the series itself (a climb of about 14km) and the return to origin at a very slow pace.

Finally, it should be noted that the COROS APEX Pro allows the use of the optical heart rate sensor while swimming. As usual, when we are underwater the performance is variable, but at least we have that possibility. 

The data won't be extremely accurate, but at least it's there to show the intensity of the workout we've done and will help with the calculation of calories consumed.

To sum up, I've had a pretty good performance in running, both at a constant pace and in intervals, as well as any other rival and at a level similar to the chest sensor.

But in cycling it is frankly bad, it has been a long time since I saw such chaotic performance when using the optical heart rate sensor in cycling training.

Wanna buy the COROS APEX Pro?

I hope that this in-depth review has helped you to decide if it is a valid device for you or not. All the work I do you can consult it without any cost, but if you want to support the page and by doing so the work I do, the best way to do that is to buy your new device through the links I provide .

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COROS APEX Pro opinion

The COROS APEX Pro is a well made watch. When you pick it up it feels like a quality product, it has an amazing battery life and the GPS performance is reasonably good. The amount of resources that COROS is using in all its models is remarkable as the update rate is very high. And if you are going to spend a lot of time at high altitudes in the mountains, it has SpO2 sensor warnings that other models do not have.

But there's the elephant in the room: the price.

It's a problem when we compare it against its competition because, despite the fact that COROS has been constantly updating the watch with more or less interesting functions (such as the track mode), its price/performance ratio is quite low. 

A watch that offers similar features is the Garmin Fenix 5. It does not have a battery life as high as the APEX Pro, but its training metrics are more reliable and we have a platform developed that goes beyond the app on the mobile phone. The feeling of the watch is very similar, and it is not complicated to find it for 150 euros less than the COROS. And for a little more than the APEX Pro we can get a Fenix 5 Plus with maps, music, wireless payments...

The Suunto 9 Baro can be found at a very similar price, having a better route navigation and with battery saving functions that place it at the same level as the COROS.

Meanwhile in Polar we find the Vantage V, although not focused for mountain or trail use, it's another option to consider with a price saving around 120€. And if what you are concerned with is power measurement, it is something that does rather better than the COROS, something that I do not value in the APEX because it simply subtracts more than it provides.

All in all, at the current price, I find this a hard watch to recommend, regardless of the advanced training metrics you may or may not be interested in.

This same watch in a range of 350-375 euros would be a perfectly valid option, because for a reasonable price it offers us a well finished watch, with an incredible battery life and that in general it works fine.

But 499€? I'm sorry, at that price I can't recommend it because I don't think it has enough features to justify it, and the fact that some of the training metrics are not well consolidated doesn't help either.

And with that... thanks for reading!