What's a Good Aerobic Decoupling Number?
Under 5% means your aerobic base is in good shape. Here's how to read the number, what counts as too low, and when to ignore it entirely.
Last updated: Jun 2026
Aerobic decoupling tells you whether your power and heart rate stayed "coupled" over a long, steady ride — or whether your heart rate drifted upward while your power held. It's one of the best simple signals of aerobic fitness, but the number only makes sense if you know how to read it.
The quick answer
Is negative decoupling good?
A slightly negative number just means your heart rate was as low (or lower) in the second half as the first — usually a sign of a strong, well-warmed-up aerobic system on an easy ride. Occasionally it can also hint that your FTP is set a little low, since the ride sat comfortably below threshold. Look at the bigger picture rather than reading too much into one figure.
When to ignore it
Decoupling is only meaningful on long, steady, aerobic efforts. Don't read anything into it on:
Trust the trend
Two nearly identical rides can produce noticeably different decoupling numbers — there's a lot of day-to-day variation. Don't compare one ride to the next. Watch whether your decoupling on similar steady rides is trending down over weeks and months. That downward trend is the real sign your aerobic base is improving.
