The day after Rosh Hashana is a fast day...and it was for me.  My fastest marathon time yet!  I chose not to fast but focused on my heart rate.  Since the prior marathon I changed my training routine to be heart rate centric.  That was a switch from using pace as my metric to my heart range.  It meant a lot slower training.  Out of the 6 days I would run, 5 would be based on keeping my heart rate in zone 3 (essentially an easy effort).

For me zone three is 135-141 bpm....which translates to a pace somewhere (at least when I started) at 10:30 to 11:00 min/mile.  I had been wanting to train at 9:08 (for a 4:15 marathon finish) so these paces felt very very slow.  At first.  After about a month, that pace turned out to be around 10:00 min/mile.  There was one day of interval training which I would do 800 Yassos or hill climbs and not pay much attention to my heart rate to slow me down (but to track for curiosity purposes).

So after about a month of this kind of training, I did notice a significant change in that my paces did get faster even though my heart rates were staying in the same zone.  I planned my next marathon to run 4:20 based on MARCO Marathon Calculator.  I was very skeptical about keeping such a slow pace for the first half of the race and only slowly progressively increasing the heart rate range I could run in, but I decided to give it a try.

It was amazing.  I never felt beat or exhausted.  My legs were happily pumping away and even at the end of the race I felt strong and could have gone another 10 miles (maybe at a bit slower pace than at the finish but still ready to go).  I am completely convinced at trying heart rate training some more.

I finished with 4:22.

ps...the following day I ran 2.5 miles and felt good (sore quads, but completely manageable).  I took the rest of the week off until a 6 miler on Friday before Yom Kippur and then a 12 miler on Sunday (after Yom Kippur)...which I ran without my heart rate monitor just to run and enjoy the weather.  I had two of my fastest miles both sub 7:50 and could have easily finished a half marathon under 2 hours.  Now that is progress!