Holger,

so you are actually kayaking around 60-70% of your max heart rate? That is great restitution/easy cardiovascular training. I got a heart rate monitor for christmas and is hooked on it now <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> Guess I'll have to look at the kayak and consider it for those long and easy cardio workouts. Only problem is that the setup time is rather longer than taking the bike or putting on the running shoes..