Age slows down the healing process
For me the term recovery run has become an oxymoron
Running at any speed just pounds the heck out of me
last year my training was less than 20mpw
run hard
bike easy
bike easy
repeat
The runs ranged from 20 to 70 minutes with the 20 minutes at 10k effort 40 minutes at 10k plus 10 secs and 70 minutes at 10k plus 20 secs
Two months before turning fifty I ran a 5k in 16:49 followed by a 5000 2 weeks later in 16:45.The return of a chronic pf problem motivated me to shutdown the running.
After 4 months of letting the heel heal I started running again.
This time only 1 day per week.I started with 1 mile uphill really hard and have progressed over the last 6 weeks to 3 or 4 miles hard as in close to race effort.The other days I ride the bike but several of those rides are 2 hour hard mtn trail type rides.It seems to be working.The idea is to stress my body with race type efforts.The body responds to the stress just like allways attempting to rebuild STRONGER.The key difference is it just takes more time to repair the damage.
Everyone heals/recovers at different rates but as we get older we all start healing/recovering slower from workouts.
Does mileage aid short term recovery?
Is there a long term price to pay?
I believe it really depends upon the person.If running 100mpw at 50 works that is great but if you start breaking down consider cross training mixed with some quality running.It might not get you that last 10 secs per mile but it just might keep you in the sport for an extra decade.