TRIMP was developed by Banister (1991) as the ‘training impulse’, a method to quantify training load.

Banisters TRIMP takes into consideration the intensity of exercise as calculated by the heart rate (HR) reserve method and the duration of exercise.

The mean HR for the training session is weighted according to the relationship between HR and blood lactate as observed during incremental exercise and then multiplied by the session duration.

TRIMP is calculated using the formula below:

time (mins) x ∆HR x y


t = duration (mins)

∆HR =  fractional elevation in HR or HR reserve

y = weighting factor

(Strava‘s Suffer Score is a modified TRIMP score)