Overtraining detection that catches it while it's still reversible.

Four signals that only mean something together

Overreaching has a signature. It just isn't visible in any single metric.

The pattern that matters looks like this: your acute training load climbs away from your chronic baseline, your Readiness Score slides for a week or two rather than dipping for a morning, your resting heart rate drifts up by a few beats, and your HRV sits below your own normal range. When those four move the wrong way at the same time, you're looking at functional overreaching — the recoverable stage — and you still have room to act before it turns into something that costs you months.

The load part comes from the acute:chronic workload ratio. Reps compares a fast, roughly weekly average of your workout load against a slower 28-day baseline, both exponentially weighted so recent sessions count more without a single monster day hijacking the number. Roughly 0.8–1.3 is the sweet spot, 1.3–1.5 gets flagged as caution, and above about 1.5 Reps calls it high risk. Worth being straight with you: those thresholds come from published acute:chronic workload research and sports scientists still argue about how well the ratio predicts injury. Treat it as a heuristic about rate of change — how fast you're adding work relative to what you're conditioned for — not a law.

Here's why none of these works alone. A single bad night, a late dinner or a glass of wine will drop your HRV without any training explanation. A head cold raises your resting heart rate. A hard training block *is supposed to* push your acute load above your chronic baseline — that's how adaptation happens; a ratio of 1.4 during a deliberate build is a plan working, not a problem. And one low Readiness Score is just Tuesday. Any one of these read in isolation gives you a false alarm or a false all-clear. That's why the overtraining indicator inside Reps won't fire on a single metric at all: it needs your resting heart rate trending up and your HRV trending down across a 30-day window before it says a word.

Overreaching vs overtraining syndrome — the difference that matters

One is a training tool with a deadline. The other is months of your life.

Functional overreaching is deliberate. You dig a hole on purpose — a heavy block, a training camp, a big month — performance dips, you feel flat, and then you back off and come back stronger a few days to a couple of weeks later. The dip is planned, the recovery is short, and the rebound is the whole point of doing it.

Non-functional overreaching is the same hole with no bounce. The rest week comes and the performance doesn't return. Recovery here runs weeks to months. Overtraining syndrome is the far end of the same continuum: months, sometimes considerably longer, with fatigue and performance loss that a normal rest block doesn't touch. The 2013 joint consensus statement from the European College of Sport Science and the American College of Sports Medicine describes exactly this continuum, and it's blunt about the diagnosis — overtraining syndrome is identified clinically, by excluding other causes first: infection, iron deficiency, thyroid problems, chronic under-fuelling, depression.

The uncomfortable part is that the boundaries aren't crisp in the moment. You usually only learn which side of the line you were on retrospectively, by how long it took to come back — days meant functional, three months meant it wasn't. There is no blood test on the morning that settles it. Which is precisely why the early, trend-based version of this question is the only one worth asking in real time: not *do I have overtraining syndrome*, but *have my load, Readiness, resting heart rate and HRV all been moving the wrong way for two weeks*. That question you can answer today, and acting on it is what keeps you on the recoverable side.

What to actually do when the pattern shows up

The intervention is almost always smaller than people fear — *if* it's early. Catching the drift in week two costs you a lighter fortnight. Ignoring it until performance collapses can cost a season. A standard deload cuts volume first and keeps a little intensity, so you shed the accumulated work without detraining; the aim is to bring your acute load back toward your chronic baseline rather than to stop moving entirely.

Then check the levers that aren't training. Chronic under-fuelling produces almost the same signature as excessive load — the gap between what you're eating and what you're doing is the thing your body responds to, not the training in isolation, and it's a more common cause than most people expect. Sleep is the actual intervention, not the nice-to-have. And your body keeps one account, not several: work stress, travel, alcohol and a lingering virus all land in the same place as your intervals. Reps logs meals from a photo and reads your sleep from the same watch, so those show up next to the load rather than in a different app you never open.

Finally, re-test rather than guess. After a genuine easy week or two you want to see resting heart rate settling back toward baseline, HRV recovering, Readiness climbing — and, most importantly, the performance returning in a session that used to feel routine. If the trends don't move after real rest, that's the point where this stops being a training question. Go and see a doctor.

On the watch you already wear

There's no band to buy and no hardware membership. Reps runs on an iPhone and the Apple Watch you already own — Series 6 or later — and reads what the watch is already recording through Apple Health. Because Reps also tracks your strength sessions and your runs, the load side of the picture reflects what you actually did rather than only what a heart-rate strap happened to catch.

And when the pattern does show up, you can ask about it. Rex, the AI coach built into Reps, is cloud-assisted and can reason over your own history — "why has my readiness been falling for two weeks?" gets an answer framed against your numbers, your baseline and your recent training, not a generic tip about resting more.