The talk test.
The simplest way to check your effort mid-run: try to speak. How much you can say tells you roughly where you are on the scale, with no watch and no strap.
How to do it
- Run for at least ten minutes first, so your breathing has settled.
- Say a full sentence out loud, or a line of something you know by heart.
- Notice what it took: easy, the odd pause, short phrases, or a word at a time.
- Match it to the scale below, and ease off or press on to land where the session wants you.
Running with someone else makes it easier: you're talking anyway.
What you can say at each level
| RPE | Talk test | Breathing |
|---|---|---|
| 1 · Very easy | You could sing. | Normal, like walking. |
| 2 · Easy | You could sing. | Relaxed and easy. |
| 3 · Light | A full conversation. | A little deeper than walking. |
| 4 · Moderate | A full conversation. | Deeper, but still comfortable. |
| 5 · Steady | Sentences, with the odd pause. | Steady and rhythmic. |
| 6 · Somewhat hard | Short sentences. | Noticeably heavier, still controlled. |
| 7 · Hard | A few words at a time. | Deep and hard. |
| 8 · Very hard | A word or two. | Heavy and fast. |
| 9 · Near max | Barely a word. | Gasping. |
| 10 · All out | Nothing. | As hard as it gets. |
Why it works
As effort rises, you pass two points where your breathing changes: first it gets deeper, then it speeds up sharply. Studies comparing the talk test with lab measurements find that comfortable talking sits at or below the first point, and that struggling to talk lines up with crossing it. It's a rough guide, not a lab test, but it's one you can use on every run.
Where it's less reliable
- The first few minutes of a run, before your breathing settles.
- Short, hard repeats: breathing lags behind effort, so it catches up after the repeat.
- Heat, altitude, illness or a cold: everything feels harder, so trust how you feel and run easier.
More on how it compares with heart rate and pace in heart rate, pace and power.