TRIMP Training Stress Calculator
Calculate Training Impulse (TRIMP) using Banister's exponentially weighted heart rate method to quantify the internal training load of a session.
📈 Exercise Science📐 TRIMP = duration × HRr × 0.64 × e^(1.92 × HRr) for men🏥 Health
Sex
Session duration (minutes)
Average heart rate (bpm)
Resting heart rate (bpm)
Maximum heart rate (bpm)
Please enter valid values.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| TRIMP Training Stress Calculator | — | TRIMP = duration × HRr × 0.64 × e^(1.92 × HRr) for men | arbitrary units |
Step-by-Step Examples
Example 1
Easy Run
60 minutes, average HR 130, rest 55, max 190, male.
- HRr = (130 − 55) / (190 − 55) = 0.556
- Weighting = 0.64 × e^(1.92 × 0.556) = 1.862
- TRIMP = 60 × 0.556 × 1.862 = 62.1
✓ TRIMP 62.1 — moderate
Example 2
Threshold Session
45 minutes, average HR 168, rest 55, max 190, male.
- HRr = (168 − 55) / 135 = 0.837
- Weighting = 0.64 × e^(1.92 × 0.837) = 3.199
- TRIMP = 45 × 0.837 × 3.199 = 120.5
✓ TRIMP 120.5 — hard
Example 3
Long Steady Run
150 minutes, average HR 140, rest 55, max 190, male.
- HRr = 0.630
- Weighting = 0.64 × e^(1.92 × 0.630) = 2.148
- TRIMP = 150 × 0.630 × 2.148 = 203.0
- Duration compensates for lower intensity
✓ TRIMP 203.0 — very demanding
Real-World Applications
Load Monitoring
TRIMP allows sessions of different intensity and duration to be compared on a single internal-load scale.
Acute:Chronic Ratio
Weekly TRIMP totals feed into acute-to-chronic workload ratios used to monitor training progression.
Cross-Modal Comparison
Because it is heart rate based, TRIMP compares running, cycling, and swimming loads on common terms.
Sports Science
Banister's TRIMP underpins the impulse-response models that formalised the fitness-fatigue framework.
Common Mistakes to Avoid
⚠️
Comparing TRIMP scores between athletes
TRIMP depends on individual heart rate reserve and the exponential weighting. It is meaningful as a within-athlete trend, not as a between-athlete comparison.
⚠️
Using an estimated maximum heart rate
Age-predicted formulas carry substantial individual error, which propagates directly into the heart rate reserve fraction and distorts TRIMP.
⚠️
Applying TRIMP to interval sessions
Average heart rate poorly represents highly variable sessions. Interval work is systematically underscored by average-based TRIMP.
Frequently Asked Questions
What is TRIMP? ▾
Training Impulse — a measure of internal training load combining session duration with heart rate intensity, weighted exponentially to reflect the disproportionate cost of higher intensities.
Why is the weighting exponential? ▾
Because physiological strain rises faster than linearly with intensity. The exponential term reflects the accelerating blood lactate response as intensity increases.
Why do men and women use different coefficients? ▾
Banister's original work fitted separate constants to observed blood lactate profiles, which differ modestly between sexes.
How does TRIMP compare with TSS? ▾
TSS is power-based and specific to cycling and running with power meters; TRIMP is heart rate based and applies across any activity where heart rate is measured.
What is a normal weekly TRIMP? ▾
There is no universal figure — it depends entirely on training volume and individual heart rate parameters. Track your own trend rather than seeking a target number.