Your first 30 days with the Coros Apex 4 46 mm

Twenty minutes on the first evening. Everything the Apex 4 46 mm will tell you for the next month is built on a heart-rate trace, a satellite mode and a screen setting, and all three are decided here.

1. 1

   Put it where the sensor works

   A finger’s width above the wrist bone, one notch tighter than feels natural for the first week, sensor window clean. The Apex 4 46 mm has a 46.2 mm case and wants a wrist of about 157 mm or more to sit flat; on a smaller wrist it rocks, and a rocking sensor is the source of half the strange numbers in month one. See wrist and case size .

2. 2

   Set your maximum heart rate, or clear it

   Every zone, every training-effect score and most of the load figures hang off this one number. If you know it from a recent hard effort, enter it. If you do not, delete the age-based default rather than leaving it: a wrong maximum quietly miscounts every run.

3. 3

   Decide about multiband now

   The Apex 4 46 mm has multiband GPS. Under trees, between buildings and in steep valleys it is the accuracy that matters; on an open road it changes nothing and costs battery — 65 h of GPS becomes 41 h with it on. Pick one mode and leave it: switching between runs makes the pace history uncomparable. See multiband GPS: when it matters .

4. 4

   Turn the backlight down, not off

   The Apex 4 46 mm has a transflective screen: it is lit by the sky and costs almost nothing to leave on, which is most of why it exists. Set the backlight to gesture and the lowest brightness you can read; the quoted 65 h already assumes the screen is on.

5. 5

   Build one data screen you will actually read

   Pace, heart rate, distance, time. Four fields, one screen, big digits. Everything else can be a second screen you swipe to when you want it. The stock screens show too much and you will read none of it at speed.

6. 6

   Download maps before you need them

   The Apex 4 46 mm shows full topographic maps, and the tiles for your region are a download over Wi-Fi or the app, not something in the box. Do it on the first evening; it is slow, and the first time you want a map is not the time to discover it is missing.

7. 7

   Load music now, decide about it later

   Music from the watch to earphones is convenient and expensive: on the one maker that publishes a figure, GPS with music is about a third of GPS alone. Load a playlist while the watch is on the charger, then treat it as a short-run feature until you have checked the battery planner for anything long.

8. 8

   Calibrate the altimeter once

   The barometric altimeter is what makes the elevation on a hilly run honest. Calibrate it once from a known height or from GPS on a clear day, and let it auto-calibrate after that.

EvoLab on the Apex 4 46 mm starts producing figures after the first run and the first night. These are the ones that arrive first, with what each one needs before it means anything.

• Training Load — after the first run, a number per session (Coros’s own scale, comparable to TSS) and a rolling seven-day total. It is the one number the whole system is built on.
• Running Fitness — a VO2max-style estimate after the first outdoor run with heart rate. Coros also derives a threshold heart rate and threshold pace from it; both are estimates until you have run hard at least once.
• Recovery Timer — hours until fully recovered, from the last session. Generic in week one.
• Effort Pace — a pace adjusted for hill and terrain, shown live. Useful from the first trail run; ignore it on the track.

The second layer of figures is where the Apex 4 46 mm earns its price, and where a new owner is most often misled — because each of them shows a value before it has the data to justify one. What follows is what each needs, on this maker’s system: the baseline takes about six weeks for base fitness, a week for load.

• Load Impact and Base Fitness — the seven-day and forty-two-day views of your training load. Load Impact is meaningful after a week; Base Fitness needs the full six weeks before it stops climbing simply because it has more data.
• Fatigue — the gap between the two. It is the number that tells you whether this week is heavier than your recent normal, and it cannot say anything sensible until Base Fitness has settled.
• Training Status — Excessive, Optimized, Maintaining, Recovery or Performance. It is a label on the Fatigue figure, so it inherits the same six-week wait.
• Marathon Level and the sleep and overnight HRV index — the HRV index needs a couple of weeks of nights to show a baseline; the Marathon Level moves only as Running Fitness and threshold move.

Coros leans on load rather than on overnight recovery, which makes it the most transparent of the systems and the slowest to say anything. After a month you have a Base Fitness line that is still rising and a Fatigue figure that is finally about you. The useful habit is to look at Fatigue on Monday morning and plan the week from it.

• Base Fitness rising in the first six weeks is the window filling, not you improving. Judge improvement from week seven.
• Training Status “Excessive” in the first month is usually a short Base Fitness making a normal week look heavy. It is right to rest; it is not right that you overtrained.
• Threshold pace and heart rate are only as good as your hardest run so far. One honest tempo session in week two fixes a whole month of underestimates.
• The system cannot see life stress or illness — see training load and readiness, and how much to believe .

Two figures on the Apex 4 46 mm are worth writing down at the end of the month, because they are the ones you will compare against later: the fitness estimate and, if the watch shows one, the morning recovery figure. Everything else is a snapshot.

These are the Apex 4 46 mm’s own figures, and the arithmetic the site’s battery guide applies to them. The quoted number is the best case; the settings you chose above decide which line you actually live on.

For a race, take a further fifth off for a cold day and then add your margin — or let the battery planner do the sum for the Apex 4 46 mm with your settings and your finish time. Everyday battery of 24 days means the charger is a weekly appointment at most.

The finder ranks the Apex 4 46 mm on the same figures this page uses. Its one-line verdict: The Apex 2 Pro rebuilt: faster, longer, with ECG — and still MIP.

Where it is strong

• Sixty-five hours all-systems and 41 h dual-frequency — multiband no longer costs two thirds.
• Maps with turn-by-turn, offline music and ECG, none of which the Apex 2 Pro had.
• Grade 5 titanium and sapphire at 64 g.

What it gives up

• Transflective screen on a €499 watch, by choice.
• No contactless payments.

If any of that is news after buying it, the finder will show you what the trade-off bought you — and what sat next to it in the ranking.