You have finished a workout and want to know how much you spent. An ordinary pedometer is nearly useless here: it can count steps, and on a stationary bike, a rowing machine or in a strength session you barely “step” at all. tri looks deeper — not at your legs but at your heart.

Counting from heart rate, not steps

While you move, the optical sensor on your wrist watches how often your heart beats. The higher the rate, the more work the body is doing and the more energy it spends. That is far closer to the truth than counting steps.

The difference is simple:

  • A pedometer sees only walking and running. A plank, dumbbells, stretching are nearly zero to it.
  • Heart rate responds to any load. You can stand still and work at your limit — the heart will notice.

So for a strength session or calm yoga a pedometer will understate the burn, and tri will not.

Why your numbers differ from a friend's

You did the same workout and spent different amounts — and that is normal. Several things affect the burn:

  • Weight. The bigger the body, the more energy the same work takes.
  • Heart rate. Whoever's heart beat faster most likely spent more.
  • Fitness. A well-trained person's heart works more economically, and for the same session they often burn slightly less than a beginner.

So do not compare your figure with someone else's. Look at your own trend — how your burn changes from week to week.

Set the workout type — it makes it more accurate

Before a session, tell the app what you are about to do: run, bike, swim, strength. This is not a formality.

Every kind of load has its own arithmetic: at the same heart rate, running and calm stretching spend energy differently. When tri knows the type, it picks the right calculation — and the number gets closer to the real one.

A couple of habits that help:

  1. Mark the start and the end of the workout so that only the working stretch is counted.
  2. Wear the band snugly on your wrist — the pulse reads cleaner, and the calories with it.

The short version: calories here are a reflection of your heart's effort, not a count of steps. The figure is an estimate, but an honest one — and genuinely useful when you look at it over time.

Sources

  • Wearables measure heart rate accurately but err noticeably on calories — Shcherbina A. et al., J. Personalized Medicine, 2017. read
  • Accuracy of energy expenditure on wearables — an umbrella review — Doherty C. et al., Sports Medicine, 2024. read

This is not medical advice. tri helps you notice patterns but does not diagnose — for health questions, see a doctor.