What your watch should know how to do ... really

Priority n ° 1: a coherent heart rate

The base is a continuously continuous pulse measure. A curve without ghost peaks, without “holes”, which follows your daily life: climb to effort, descending to calm, stability at rest. Consistency over several days has more than the “best snare”.

Priority n ° 2: a simple and exportable ECG

An ECG with a wrist lasts 30 seconds. Well done, he can document an episode (palpitations, irregularity) and produce a PDF to show the doctor. The interest is not to “test ourselves” every day. The interest is to have a route when something happens, and to be able to share it easily. On compatible models, this is the hard point to check before purchase: availability of the ECG app in your country, export, clarity of the result.

Priority n ° 3: detection of arrhythmia in the backpan

Modern watches can monitor your rhythm and report a diagram compatible with atrial fibrillation (FA). It is a sorting alert, not a diagnosis. It encourages you to launch an ECG and/or consult. Again, availability depends on countries and software versions; Check for France.

Priority n ° 4: simple trends to read

• FC rest: your “basic line”. She reflects form, fatigue, stress.
• Variability of the FC (HRV) Nocturne: a load/recovery signal. Read it on 7 to 28 days, not day by day.
• Context: sleep, activity, caffeine, fever, heat. Without context, an isolated value tells little.

How it works, without jargon

The optical sensor (PPG)

It sheds light on the skin, reads the light changes linked to blood flow. It is sensitive to placement, tightening, temperature, sudden movements. A cold wrist or too loose strap is enough to distort reading. Hence the simplest advice: wearing the watch a tightened notch for effort, a more cowardly cran on a daily basis. Clean the back of the case. Let the skin breathe.

ECG has a derivation

Two electrodes (back of the watch and crown/button) capture the electrical activity. You hold your finger for 30 seconds; The trace watch. Class algorithm: sinus rhythm, atrial fibrillation, indeterminate. You then export a PDF. It is not a clinical ECG 12 derivations, but it is a useful snapshot at the right time. On Apple Watch Series 10 for example, the ECG app is marked CE, and the notifications of arrhythmia are available in several EU countries, including France.

Arrhythmia detection (continuous)

The watch scan your pace at regular intervals. If the pattern looks like a repeated FA, it notifies you. There are age conditions, countries, and limitations (it is not “permanent”). It is not a vital alert system; It is an evidence of evidence.

Precision and reliability: which makes the difference

Precision is proximity to reality. Reliability is consistency.

• A slightly “quirky” but stable watch can guide you better than a very fair, sometimes fanciful model.
• Reading with intense effort remains delicate on the wrist (shocks, vibrations, vasoconstriction). Simple tip: couple a thoracic belt during “nervous” sessions. Keep the watch for the rest (rest, endurance, sleep).

The variables you control

• Placement: a finger above the wrist bone, sensor in frank contact, clean skin.
• Temperature: Reheat the wrist in winter before an outlet.
• Movement: Reduce forced flexions of the wrist (too tight bicycle handles? Remember to adjust).
• Update: Accept updates. Algorithmic corrections often refine the curve.

How to judge a watch “in real life”

• Do three tests upon receipt: 30 -minute walk, moderate cardio session, quiet ECG. Compare consistency, not perfection with a beating.
• Follow 14 days. Look at the rest FC, the night profile, recovery. You have to “recognize” your daily life.

Concrete uses, without theater

For effort

Your watch serves as a limiter. Are you going a little high? You come back from a notch. You maintain a regular tempo. After the session, you check the descent: if it is slow, you adapt the next one.

At the office

A rest FC that rises over several days? Bad sleep? Stress? You anticipate: sleep earlier, light outing, breathing. No drama. Adjustments.

Night

Night trends are rich: FC, HRV oscillations, agitation. They tell sleep debt or recovery. We read on the week, not the day after the Pizza evening.

When the alert watch

Alert of arrhythmia, FC abnormally high at rest, palpitations + discomfort: we sit, we redo a measure in calm, we launch an ECG if possible, we note the time and the situation, we consult if the signals are repeated or if we do not feel well. Simple, square.

Top 5 best connected watches for cardiac follow -up (2025)

Selection criteria: Precision and consistency of the optical sensor, reliable and exportable ECG, detection of arrhythmia available in France, readability of data, autonomy, and software maturity. Each brand mention is justified by these criteria. An informed watch; Only a professional interpreter and diagnostic.