This is the one I was really dreading. Repeated W6 last week and found it HARD. But it's been fine. Mind I was going very slowly, held back a lot; didn't get tired, breathed in through my nose and actually had that little bit extra to speed up for the last 60 secs as Laura suggests. And my glasses steamed up for the last 5 minutes.
I've gone back to wearing daps as I had a bit of knee pain last week.
What a good scheme this is. I've never done exercise in my life - I was the asthmatic speccy kid who hid in a cupboard with a good book every school sports day.