I'm 33, my PB for 5k is 16:3x and I have ran 77:3x for half.
Last week I ran 15 mile long run in 1hr 40min averaging 6:42/mile. It was a moderate effort run, I was breathing normally, at no point it felt hard. I naturally picked pace slightly with each mile.
Today I ran 12 mile long run in 1hr 20min averaging 6:41/mile but in quite windy conditions. It was still a moderate effort and no struggling. As last week I was picking my pace slowly over the duration of my run.
So I am wondering should I stick to this pace as long as I can cruise freely at this pace or should I better slow down for my long runs? I know that aerobic base building is basically a function of time so it would seem that I would reap more benefit by running slower and longer but I was wondering what are the benefits of running faster vs longer?