Your Watch's Recovery Score

You wake up, reach for the phone, and it tells you you're 34% recovered. You haven't sat up yet.

There's something in that number, and much less than the interface implies.

The measurement underneath is heart rate variability — the variation in the gap between consecutive heartbeats. When your parasympathetic (rest and digest) system is dominant, the gaps vary more. Under sympathetic (fight or flight) drive, they vary less. It's well established in the research and it's the best consumer signal we have for accumulated stress.

It's also extremely noisy. A late meal moves it. Two glasses of wine move it a lot. A cold you don't know you have yet, a warm bedroom, a strap that sat differently, the time you went to sleep — all of it moves the number. A single morning's reading tells you very little, and comparing your number to anyone else's tells you nothing at all, because the useful range varies enormously between individuals.

Then there's the layer on top. Whoop, Oura and Garmin all take the same underlying measurement and turn it into a different score, weighted by decisions each company made. Yours will confidently tell you to take a rest day because your bedroom was warm!

My view, and it's an opinion rather than a finding: glance at the trend, ignore the daily score, and don't let a wearable make decisions your body is capable of making. If you feel fine, train. If you've slept badly three nights running, lower the load and keep the session.

What a good coach does with this is nothing. They watch how you move in the warm-up, they've seen you three times this week, and they'll adjust the number before you've mentioned a score to anyone.

When the trend does fall for a fortnight, the answer is rarely to stop training. Drop the load and keep the sessions — volume and intensity down, attendance unchanged. The habit is harder to rebuild than the fitness, and a fortnight off tends to become six weeks.

If you want numbers that earn their place, two are better than HRV. Resting heart rate, taken over weeks, is a straightforward marker of aerobic fitness and it moves when your training is working. And total time asleep — not the sleep score, the hours — which is the one thing on the device you can act on directly tonight.

Look at the seven-day trend, once a week, on the same day. If it's falling and you feel flat, act on it. If it's fine and today's score says 34%, get to the gym.

A coach who has seen you three times this week is a better sensor than a strap. Free, no-obligation 15-minute chat with Jeremy or Beth at crossfitchiltern.com.