I agree that slowing down is important for the additional mileage. As I have watched my mileage increase into the 70s this training block, my pace on a lot of runs is around 7:30 because of my overall fatigue. Most of the fatigue is from those 16-20 mile long runs that seem to take extra time to recover from.
Training update for 8/5- 8/11:
69 miles total.
Monday: 3 miles easy around 7:45 avg probably. sore from from long run the previous night where I did 10 miles right under marathon goal pace (15 total)
Tuesday: Began workout very late after a long day... 4 mile warmup, 3 mile tempo with 5:55 avg, 1 mile cooldown. Still not feeling great.
Wednesday: 12 fairly easy in 1:25. 7:10 avg.
Thursday: 6 miles easy and strides
Friday: Yasso 800s. 10x800 w/ roughly 500m jog rest (2:30 rest on avg). Averaged about 2:42 for them! not sure really what to make of this workout... Was starting to get pretty fatigued at the end.
Saturday: 12 miles on hilly route. 1:20:48. Ran with some fast guys and averaged 6:44. Hurting on all the hills.
Sunday: tried to do 20, but got in 17. 2:09:30. 7:37 avg. Ran at sunset. It was very hot and humid. I was also feeling the fatigue of Friday's workout and Saturday's fairly hard longer run.
Overall solid week. Only 3 weeks away from marathon date! Time to start the taper.