WHOOP · Your reading
What WHOOP Strain should I aim for today?
Aim for the Strain your Recovery can pay for. On a green morning a high day (14–17) is fair game; on yellow, moderate (10–13) usually fits; on red, keep it light (0–9). Keep all-out days (18–21) for races and key sessions.
What the score is made of.
WHOOP Strain measures your body’s total exertion on a scale from 0 to 21. WHOOP scores it for the whole day and for each activity, so a stressful afternoon adds Strain as well as a workout.
It combines two loads. Cardiovascular load comes from your heart rate: the higher it climbs and the longer it stays up, the more Strain you build. Muscular load estimates the work your muscles, bones and joints do in strength, HIIT, yoga or Pilates, which heart rate alone undercounts.
The scale isn’t linear. WHOOP describes it as logarithmic, so going from 10 to 14 takes far more than going from 0 to 4. It’s also personal: two people doing the same session will usually score differently.
WHOOP also sets an Optimal Strain each day, a target based on your Recovery score, the Strain you’ve already built that day and, if you use it, your menstrual cycle phase.
What each band means for tomorrow.
| Score | Level | What to do today |
|---|---|---|
| 0–9 | Light | Little to recover from: WHOOP calls this room for active recovery. Right for a red morning or an easy day, but if every day sits here, plan a harder one for the next green morning. |
| 10–13 | Moderate | Maintains fitness, per WHOOP, and tomorrow should be largely unaffected. A sensible target for a yellow morning or a steady training day. |
| 14–17 | High | The band WHOOP says builds fitness. Expect tomorrow’s HRV and resting heart rate to show it, so pick this on green mornings and follow it with an easier day unless Recovery comes back green. |
| 18–21 | All Out | Maximal effort that WHOOP says is hard to recover from. Keep it for races and key sessions, plan tomorrow light or switched, and let Recovery say when the next hard day is due. |
Educational, not medical advice. With chest pain, a fever or feeling unwell, rest and see a doctor.
What the score can’t see.
Strain counts load; it doesn’t judge it. A 15 can be the best session of your month or the one that tips a tired week over, and the number alone can’t tell which. What matters is load against what you’re used to: research on training load links rapid jumps, more than hard training itself, to soft-tissue injuries. Build week on week rather than chasing a bigger number.
One day’s Strain is one day. Read it across the week: a week of 16s with Recovery sliding is a different story from two 18s with green mornings between them. And Strain can’t see a niggle or a day you ate too little.
Pick the target in the morning: Recovery sets the ceiling, your plan sets the purpose. px reads your WHOOP Strain every morning alongside your sleep, HRV, resting heart rate and calendar, and sizes the day from all of it, telling you why.
Sources
Your WHOOP scores, explained.
Questions
What is a good WHOOP Strain score?
There isn’t one number. WHOOP sets four bands: light 0–9, moderate 10–13, high 14–17 and all out 18–21. A good Strain is the one that matches your Recovery and your plan.
Why is it so hard to push WHOOP Strain higher?
Because the scale is logarithmic. WHOOP says it’s easier to go from 0 to 4 than from 10 to 14, so each point near the top takes much more work.
Does Strain affect my next Recovery?
Not directly. WHOOP bases Recovery on overnight signals such as HRV and sleep, but says higher Strain can lead to lower HRV and a higher resting heart rate the next day, which then shows in the score.
Can I get high Strain from lifting weights?
Yes. WHOOP adds muscular load to cardiovascular load, so strength work can raise Strain without a high heart rate. Linking your exercises after a session, or logging sets in Strength Trainer, makes the estimate more precise.
px reads your WHOOP Strain every morning.
Alongside your sleep, HRV, resting heart rate and calendar, so the day is sized from all of it, not one number. You get the plan and the reason.