Rest. Light. Moderate. Push.

Wednesday morning. Coffee. You don't know what your body can hold today.

You slept seven hours. You don't feel terrible. You also remember last Wednesday, when you didn't feel terrible at 7 a.m. and lost Thursday and Friday to a crash you didn't see coming.

If your energy varies because of illness, hormones, or recovery, listen to your body is advice that lies on the good days. Pacing for chronic illness means catching the signal before the feeling catches up — and the signal is already on your wrist.

Body Insights reads what your Apple Watch recorded overnight — HRV, resting heart rate, sleep, wrist temperature, and if you wear a CGM, overnight glucose. It weighs those signals against your own baseline, not a healthy-athlete one. Then it suggests, in plain language, what today can probably hold. "Today, take it slow." Or "Today has more in it."

The reading is a second opinion. You still decide.

A recommendation engine, not a command engine.

Most readiness apps hand you a number. 64. 78. You're left to translate. Body Insights hands you one of four words — rest, light, moderate, push — and one or two sentences underneath that explain why.

Many mornings sound like this: "Today, take it slow. Your overnight recovery was lighter than usual — HRV dipped and your heart rate is elevated against baseline." Other mornings sound like this: "Today has more in it. If you wanted to push, your numbers say you can."

The 0–100 score is there if you want to see it. The recommendation is in words because that's what your morning actually needs.

How the recommendation is built.

Body Insights reads five signals against your own baseline — your resting heart rate trend, last night's sleep, your energy reserve, recent autonomic load, and any accumulating physical strain. Each gets a different say in the answer.

RHR carries the most weight, because it's the cleanest signal the body offers for systemic load. Sleep and energy reserve come next. Stress sits underneath. Visible strain — like an elevated walking heart rate — can pull the recommendation down even when the rest of the picture looks fine.

Safety overrides can bypass the recommendation entirely and suggest rest: if you report feeling sick, if recovery is still elevated from a previous heavy day, or if critical metrics are running far above your baseline. The overrides are conservative on purpose. A wrong "push" call costs you days; a wrong "rest" call costs you an afternoon.

Pacing — what it actually means.

If you have ME/CFS, Long COVID, fibromyalgia, or any condition that punishes overexertion, you've probably heard the word pacing. The clinical concept it refers to is the energy envelope.

Described in the Institute of Medicine's 2015 diagnostic criteria for ME/CFS and refined by the Workwell Foundation and Leonard Jason's research group at DePaul University, the idea is this: people with post-exertional malaise have a daily energy budget that is smaller than it feels in the moment. Spending under it is sustainable. Spending over it triggers a crash that can last days. The art is staying inside the envelope on the days the envelope is small.

Two things make the envelope hard to honor. The feeling lags the signal — you feel fine at 9 a.m. and crash at 4 p.m. Good days lie — a genuinely better morning tempts you to spend like a healthy person and overshoot. A second signal helps. HRV moves before symptoms.

Body Insights is not a diagnosis. It's a daily reading that names the envelope.

You can always override. The app won't argue.

This is a recommendation engine, not a command. Body Insights does not decide your day — it gives you a second signal you didn't have. If you know your body, your context, or the day ahead in a way the numbers don't capture, you override. The app remembers what you did and what happened after, so the model gets quieter and more accurate over time.

The voice of the app is suggests, never tells. "Today has room for moderate effort" — not "You will train moderately." A friend across a kitchen table, not a coach with a whistle.