What does running at 70% effort mean?
Running at 70% effort means moderately hard: you can still talk, but only in short sentences. It's a 7 on a 1–10 scale of how hard the running feels, the scale coaches call RPE (rating of perceived exertion). It is not 70% of your top speed, and not 70% of your maximum heart rate.
The effort scale
Fartlek sets every rep, recovery and easy run as a percentage on this scale, from 30% to 100% in steps of 10. Each level has a name and a check you can do while you run:
| Effort | Level | How it feels |
|---|---|---|
| 30% | Very easy | Walking pace or the gentlest jog. |
| 40% | Easy | Relaxed jog, easy to chat. |
| 50% | Comfortable | Easy running, full sentences. |
| 60% | Steady | Still chatty, breathing deeper. |
| 70% | Moderately hard | Short sentences only. |
| 80% | Hard | A few words at a time. |
| 90% | Very hard | A word or two, tops. |
| 100% | All out | Nothing left in the tank. |
How it maps to RPE
Divide by ten: 70% is an RPE of 7, 90% is 9, and 100% is 10, everything you have. The talk test places you quickly: full sentences mean 60% or less, short sentences about 70%, a few words at a time 80%, and a word or two 90%.
Which effort for which run
- Easy runs and recoveries: 30–50%. Relaxed enough to chat. Most of your weekly running belongs here.
- Steady and long runs: 60–70%. Breathing deeper, still in control.
- Tempo: around 70%. Comfortably hard: you could hold it for a while, but you couldn't chat.
- Intervals: 80–90%. Hard reps of 1 to 5 minutes, like the Norwegian 4x4 or Yasso 800s.
- Short bursts and strides: 90–100%. Fast but relaxed, 10 to 30 seconds, like strides or Tabata.
Why effort instead of pace
Pace says how fast you're going. Effort says how hard that is for you today. Heat, hills, wind, a bad night's sleep or the last rep of a hard session all change what a given pace costs, and running by effort keeps the session doing its job on those days, with no zones to set up. Heart rate is useful on long, steady runs, but it lags behind short reps: in a 30-second burst it is still climbing when the rep ends.
Is 70% effort the same as 70% of max heart rate?
No. 70% effort is about how hard the running feels. 70% of your maximum heart rate is, for most runners, an easy effort you can hold a conversation at.
How Fartlek uses it
Every run in Fartlek, from the workout library to the runs Pete builds and your training plan, gives each step a target on this scale. Voice, color and haptic cues mark every change of effort, even with your phone locked, and the app includes this guide for when you're not sure.