' I don't know from pace so I thought OP's daily runs were high intensity.'

It doesn't have to do with pace Everybody has a different speed which is not really in itself a measure of intensity - for one person, 8 minute miles could be the fastest they could run and for another it could be glacially slow, even if they are running with the same effort. To run 6-7 miles a day, I would guess that 8 minute miles is an easy pace for the OP - otherwise, they would quickly burn out completely. Their hard pace is probably much much speedier. 8 minute miles are awesome though - I wish I had that speed!

Re: Rollerblading. Rollerblading is great - it's also great crosstraining for running I like ice skating for that reason. Sometimes there are rollerblading groups - I think there is a roller derby player here on the forum who might have training tips.