bogydave

Garmin 520, HR & Cadence
After today's ride it displays
" Recovery time : 57 hours "

How is this calculated ?

Seattle Forrest

Garmin licenses this software from a company called Firstbeat. They probably have a white paper about how it works. The gist of it is that it uses HRV to asses your recovery state, and it needs about a week of riding data to get to know you.

bogydave

Full year with it now.
Not that I follow it,
many times
it says 72 hours, I ride 20 miles the next day & it says 36 hours

More curious about it than
using it for ride recovery or
when to ride.

yamsyamsyams

It calculates this for running as well. I just ignore the actual hours listed but use the number to quickly verify how I feel after the workout. Eg if I started out sluggish and felt sluggish at the end, i would expect a higher recovery number. If it’s low then perhaps I just feel off or was lazy that day.

DrIsotope

If you haven't done a LTHR test and input the numbers into Connect, the Recovery Advisor is worthless. The recovery advisor time on my last double metric was only around 35 hours. Unless you're riding for hours near threshold (and therefore glycogen depletion and complete exhaustion,) you'll never see a 72 hour recovery time.