Well I've done w6r1, but found doing 18mins with walking breaks harder today than doing 20 mins run did on Thursday.
Felt a distinct lack of energy/enthusiasm in the 1st run, although it did feel tougher I was able to muster some energy to up the pace 30 secs from the end of the last run, spurred on by my friend.
But just remembered! I drank 2 pints of Boddingtons last night? And not enough water after the beers & before the run this morning had a cup of tea and only a half a pint of water before I ran.. My fault! It's not enough!