COROS Apex vs. Suunto 5 in Daily Tracking

Coros Apex and Suunto 5 are two of the current contenders in training/fitness watches at around 300 dollars. Let’s have a look at some comparison data in 24/7 tracking…

Full disclosure: I received the Apex from Coros, for reviewing as/how/if I see fit; the Suunto 5 came from Suunto in my role as external tester for them, i.e. to try out new watches and firmware and give feedback. None of it is paid (except in the form of the watches); none of my writing is influenced by the companies in any way.

Step Tracking

The main way that everyday activity is tracked and quantified continues to be via step counts.

This makes for an easy measure. And it is reinforced by the popular idea that taking 10,000 steps a day means that you lead an active life.

Thus, every fitness-related device now tracks steps, problematic as it can be to do so from the wrist.

A Note on Methodology

In my testing, I have been switching the devices from one wrist to the other; I think I finally ended up with them having been on each wrist for somewhat equal times.

For a still-more-scientific approach, I’d like to differentiate the values into those from left vs. right wrist, but who’s got the time to always write that down?

Maybe later.

Step Tracking Results

Now, here are the counts from Suunto 5 and Coros Apex over a bit more than two weeks of continuous tracking:

Suunto 5 vs. Coros Apex: Step Tracking
Suunto 5 vs. Coros Apex: Step Tracking

So, we have “somewhat” different step counts – meaning, there have been differences up to 1.5x in step counts, with 10,000 steps counted by the Suunto 5 and 15,000 steps counted by the Apex.

But, there are often the same step counts, and the trends are similar. A day that was more active according to the Suunto 5 was also more active according to the Coros Apex.

A Note on “Sleep Steps”

Both devices also seem to have become rather good at separating motion during sleep from steps; when I remembered to check, I woke up (or rather, sat on the toilet…) and saw 20-40 steps on the watch; relatively appropriate for the first or second trip to the bathroom.

Calorie Tracking

The Suunto 5 tracks/displays both “active” calories, expended by being active, and total calories. The latter includes active calories and adds the (probable) basal metabolic rate, i.e. how many calories are expended just for maintaining body temperature, etc.

The Coros Apex only tracks active calories, expended while doing more than just sitting around.

Thus, the calories measurement I compare here is that of active calories:

Active Calories Tracking, Suunto 5 vs. Coros Apex
Active Calories Tracking, Suunto 5 vs. Coros Apex

Again, we have different calculations most of the time, but rather similar trends. More or less active days are reflected by more or less expenditure of calories.

Steps vs. Calories

We could of course just try to compare the charts above, but let’s make that easier with a dedicated scatter chart, plotting step counts vs. active calorie counts:

Calories vs. Steps, Coros Apex vs. Suunto 5
Calories vs. Steps, Coros Apex vs. Suunto 5

This shows – as it should if things are alright – that the relationship between steps tracked and calories calculated is a direct one…

… but also, again, that the Suunto 5 tends to track fewer steps and active calories, the Coros Apex more.

It makes it rather more obvious that there have been days during this time period when the Coros Apex measured/calculated quite a lot more of both than the Suunto 5 did.

Sleep Tracking

Good activity needs good sleep… or something.

My sleep isn’t exactly recommendable, but the tracking has been all the more interesting:

Sleep Duration, Suunto 5 vs. Coros Apex
Sleep Duration, Suunto 5 vs. Coros Apex

Apart from the problematic day 13, when the Suunto 5 tracked a good hour more sleep than the Coros Apex, sleep tracking data from both watches has been surprisingly similar.

Yes, there are differences, but they have typically been around 15-30 minutes, which is not much for such a measurement. (Even if, yes, it does mean that one should not see those measures as absolute numbers, but rather use them as trends and for averages.)

It is interesting, also, to see what times the watches “thought” I was falling asleep and waking up:

Times I (supposedly) fell asleep and woke up, as measured by Coros Apex vs. Suunto 5
Times I (supposedly) fell asleep and woke up, as measured by Coros Apex vs. Suunto 5

Apart from days 12/13, where these times differ more (which explains the difference in sleep duration seen above), the Suunto 5 and the Coros Apex have me falling asleep and waking up at very similar times.

Of course, not showing both times in one graph would make the differences more pronounced, but they were (usually) only minutes apart, at most quarter of an hour.

Coros App Sleep Bug

Unfortunately, I have to mention that the sleep tracking with the Coros Apex did not work quite as well as the above comparison makes it look.

Three out of the 16 days I used the Coros Apex and the Suunto 5 for my daily activity and sleep tracking, I did not get sleep tracking data in the Coros app – and duplicate sleep data with the exact same results shown twice, on other days.

Recently, I have not seen any missing data anymore, but a duplicate entry has appeared again.

So, Coros has some bugfixing to do. Seeing how they have been doing, this is likely going to be fixed very soon, though.


As per the usual, I would not dare to conclude that the one or the other watch has definitely been more accurate; there is no way to judge that justifiably.

There are differences, we will also compare other devices to see what results they provide.

All in all, it looks like both serve their purpose of giving an impression of how active and how well-rested (or not) their user is.

The Suunto 5 would also give a score for sleep quality, which could be quite interesting to track; the Coros Apex shows more information about different sleep phases…

2 responses

  1. Dulko Avatar

    Hey, how big is the daily HR tracking impact on the battery? What about HR values collected by the watch during the day? Do they seem reasonable? Thanx.

    1. On the Coros Apex, it’s hardly noticeable. On the Suunto 5, a fair bit. Hmmm, I could add some daily HR data, in comparison. It doesn’t compare so nicely, but still…

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