So this way my creative attempt at trying to replicate a long run with marathon pace at the end. I did 2 hour hilly bike ride then 60 minutes of 3 minute, 1 minute intervals on the cross trainer at the gym. Two quick stops on route - one to come home to get a bike lock which I had forgotten and one quick change at the gym (was wearing more clothes on the bike today). Felt pretty strong throughout but was taking in lots of fuel. Intervals were tough at the end (but that was the idea) and heart rate went up nicely.