Ruffier-Dickson Index Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/9/2026
The Ruffier-Dickson index is calculated with [(pulse after effort − 70) + 2 × (pulse at 1 minute − resting pulse)] ÷ 10. For a resting pulse of 60, a post-effort pulse of 120, and a 1-minute pulse of 80, the IRD is 9, a "very weak" adaptation on the classification grid.
Explanation
The Ruffier-Dickson index (IRD) uses exactly the same three pulse measurements as the classic Ruffier index — resting pulse (P0), pulse immediately after 30 squats in 45 seconds (P1), pulse exactly 1 minute after the effort ends (P2) — but combines them in a DIFFERENT formula, which gives double weight to the recovery gap (P2 − P0) rather than simply adding up the three raw values. This weighting reflects a slightly different idea of what defines good cardiovascular adaptation: how fast the heart drops back toward its resting rate after effort (recovery) counts here more than the raw intensity of the spike during the effort itself. The two indices, Ruffier and Ruffier-Dickson, each have their OWN classification grid (the IRD's is finer, with seven categories versus five for the classic index): their numeric results are never directly comparable to each other, and which of the two indices is being used should always be specified when tracking someone over time, to avoid mixing two different scales. As with any field test, the IRD remains an indicative estimate of cardiovascular adaptation to effort, not a medical diagnosis.
Example: P0=60, P1=120, P2=80
Inputs
Resting pulse: 60 bpm. Pulse after effort: 120 bpm. Pulse at 1 minute: 80 bpm.
Calculation
IRD = [(120 − 70) + 2 × (80 − 60)] ÷ 10 = [50 + 40] ÷ 10 = 9.
Result
An IRD of 9 corresponds to a "very weak" adaptation on the classification grid.
Frequently asked questions
Why does the Ruffier-Dickson index give a different result from the classic Ruffier index for the same measurements?
Because the two formulas combine the same three pulse measurements in mathematically different ways: the classic index simply adds up the three values, while the IRD gives double weight to the recovery gap between the 1-minute pulse and the resting pulse. The two indices therefore measure slightly different aspects of cardiovascular adaptation, each with its own classification grid, and they aren't interchangeable.
Which index should I use, Ruffier or Ruffier-Dickson?
Both remain used in practice, often calculated together from the same three pulse measurements for a more complete picture. What matters most is staying consistent when tracking someone over time: always compare the same index from one session to the next, never today's IRD against a classic Ruffier index from an earlier measurement.
What does a result above 10 on the IRD scale mean?
An IRD above 10 falls into the lowest category on the classification grid, associated with cardiovascular adaptation considered poor and a recommendation for further evaluation. As with any unusual result on a field test, advice from a healthcare professional is recommended rather than interpreting this single number in isolation.
Are there other post-exercise cardiac recovery tests?
Yes, see also our cardiac recovery calculator, based on a different effort protocol and a single threshold (the Cole et al. reference), rather than the three measurements and seven-category grid used by the IRD.