What Is TRIMP? The Heart Rate Training Load Formula Explained

TRIMP turns your heart rate during a workout into a single number representing training stress — helping you balance load and recovery without guesswork.

7 min read
Beginner-friendly
ESC 2021 sourced
LIVE · 14 / 60s
9:41● ● ●
Measurement complete
Your HRV today.
68 ms
Heart-rate variability
Excellent
RMSSD
68 ms
+6% · parasympathetic
SDNN
91 ms
+3% · autonomic
7-day trend
↑ up 4%
What is HRV

The variation between heartbeats — your nervous system's report card.

RMSSD vs SDNN

Two metrics, one number. Why Pulse shows both — and which to watch.

TRIMP load

Training-impulse: your weekly training load, in one chart.

The protocol

4 steps. Sixty seconds. Done before your coffee.

  1. 01
    Morning

    Understand the Formula

    TRIMP = Duration × Average HR × Intensity Weighting. The higher your heart rate relative to max, the more stress each minute contributes to your daily score.

  2. 02
    60 sec

    Log Your Workout HR

    After a session, open Pulse Rate and record your workout duration. The app uses your heart rate zones to calculate a TRIMP score automatically.

  3. 03
    Read

    Compare Day-to-Day Load

    Review your weekly TRIMP totals in the trends view. A sustainable training week typically shows gradually increasing load with planned lower-load recovery days.

  4. 04
    Daily

    Use Load to Plan Recovery

    When your weekly TRIMP spikes significantly, your body needs more time to adapt. Use the morning HRV reading to confirm readiness before your next hard session.

What you'll see in Pulse

Your progress, exactly how the app shows it.

The same chart that lives on your iPhone's Progress screen — rebuilt so you know what you're looking at.

Wellness Index trend
82 / 100 Excellent
Last 30 days
100 75 50 25
Excellent (80+) Borderline (40–60) Very low (0–40)
Excellent 80+

Outstanding score. Your key heart metrics are above normal.

Normal 60 – 80

Most healthy adults fall within this range.

Borderline 40 – 60

Not necessarily alarming — but worth monitoring.

Very Low 0 – 40

If this persists, please consult a healthcare professional.

Bonus · TRIMP

Training Impulse, decoded.

TRIMP = duration × intensity. A 60-minute easy run scores about 70 TRIMP. A 30-minute interval session scores 110. Pulse adds them up daily and tells you when your week is too light, just right, or about to overcook you.

80–140
Optimal weekly load
140–200
Stretch (watch HRV)
200+
Overreaching
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