Load shows how hard the day was on your body — on a scale from 0 to 21. It is not calories and not steps: it is how much you actually taxed your heart and body. An easy walk adds a little, a hard interval session adds close to the maximum.

How we measure it

The basis is your heart rate across the whole day, not just during a workout. The longer and the higher it stays above rest, the more load adds up:

  • a short effort at a high heart rate and long work at a moderate one can contribute the same;
  • the whole day counts — work, stairs, stress, not only the gym;
  • the scale is non-linear: getting from 0 to 10 is easy, while every next point up to 21 comes harder — that is genuine work at the limit.

Why the scale stops at 21

By design: 21 is your very hard day, something you work up to rather than repeat every time. Most days live in the 8–14 range, and that is normal. Chasing the maximum daily is a direct route to overtraining.

What matters is the balance with recovery

Load on its own is neither good nor bad. It means something in a pair with recovery:

  1. High recovery + high load — a productive day. This is how fitness grows.
  2. Low recovery + high load — you are borrowing. Occasionally fine, constantly not.
  3. High recovery + low load — there is resource to spare, you can add.
  4. Low recovery + low load — your body is resting, and it is right to.

Do not chase the number for its own sake. Take your cue from recovery: it tells you today's ceiling.

Sources

  • Sharp spikes in load raise injury risk; gradual growth protects — Gabbett T. et al., Br. J. Sports Med., 2016. read
  • Training load can be quantified from heart rate and effort — Foster C. et al., J. Strength Cond. Res., 2001. read
  • HRV helps dose load according to recovery — Plews D. et al., Sports Medicine, 2013. read

tri helps you plan load but does not replace a coach or a doctor. Sharp pain, dizziness or severe breathlessness are reasons to stop and see a specialist.