My resting heart rate told me nothing my legs had not already said

Recovery telemetry is sold as early warning, but most of its alerts arrive after the athlete already knew.

The watch buzzed at six in the morning to inform me that I was under-recovered. I had worked that out at some point during the night, mostly by lying awake with calves that felt like they had been filled with sand.

This is the honest state of most recovery telemetry. Heart rate variability, resting pulse, sleep staging, the composite readiness score that vendors love because it hides the arithmetic. These things are real physiological signals. They are also, for a trained athlete paying attention, largely redundant with the simplest question available, which is how do you feel and how do the legs feel going up the first flight of stairs.

Where the numbers earn their place is not the individual morning. It is the trend nobody would notice by feel, because feel adapts. An athlete four weeks into a heavy block has recalibrated their sense of normal, and a resting rate that has crept up six beats over that period is genuinely new information. Same with the athlete who is fine every morning and whose variability has quietly stopped responding to easy days. Those are slow signals, and slow signals are exactly what human perception is bad at.

The daily score, by contrast, is mostly noise wearing a uniform. Sleep position, a late meal, a cold room, an argument, alcohol from two nights ago. Present a runner with a red morning and you have changed the session before it started. I have watched athletes talk themselves out of a good workout because a wrist sensor with an optical view of one artery had opinions.

So my rule is unfashionable. Athletes should not see the daily number. Coaches should see the rolling one. If that sounds paternalistic, consider that we already do this with every other measurement in the sport: nobody hands a thrower the raw force trace and asks them to self-regulate from it.

There is a second cost that gets ignored. Every one of these devices trains the athlete to outsource a skill they will need for the whole of a career, which is reading their own body under fatigue. That skill is built by being wrong about it a few hundred times.

Wear the thing. Look at the month, not the morning. And if the legs feel like sand, you do not need permission from a wristband to go easy.