a short session is a lot better than no session and also often better than a full-on effort that leaves you destroyed for days.
Remember - that the recovery bus when you get fitter and faster, the hard sessions just damage you.
Ye that is what I was thinking. No point damaging myself too much I guess. It also won't take much at the moment to make me considerably fitter.
Do the hard sessions (even shorter ones) regularly and you'll get fitter - simples!