I started back in the days with a fitbit, loved tracking of exercise and steps. Then the heart issues arrived, and I am even more attached to my trackers, LOL. Nowadays I am wearing a "Withings" watch, with the ECG capability. Love how the battery is definitly way more durable than the fitbits (that was my issue with them).
To make a long story short, the first fitbit had tried to warned me than my HR (heart rate) was going steadier and steadier up, for a few days, before my cardiac decompensation... I thought the tracker was getting unreliable. Guess I can laugh about it today.
A few weeks after, the same fitbit showed clearly that the HR was getting back up, leading me to see the doc the same day for an ECG (this was before my open-heart surgery was scheduled) - and the ECG showed I was again in tachycardia and atrial fibrillation. This time I listened to the thingy
as it probably avoided me a second decompensation.
Finally, now I use that Withings, with the ECG ability, saturation measure, and ability to detect atrial fibrilation. In June 2021, a day I was feeling off, it alerted me to a return of atrial fibrilation, confirmed by the emergency room (spent several days in the ER, and that led to my surgery last summer) - and it stopped detecting it just a few hours before the cardiology team told me I was back to normal rythm .
When I caught Covid in June, I was quite glad to be able to monitor my ECG and saturation by myself, so I'd know if things turned south and could react quickly.
So, short answer, yes I use a tracker, love it, and even had its accuracy medically proved, LOL!