Heart rate monitor definatly - never, ever go off the machines they're crap!

Do you know what hr you should be aiming for? If you like I can work it out for you. Just let me know your age and what you want to achieve (aeorobic conditioning or fat loss).

HTH

And BTW well done for getting a hr monitor they're invaluable - takes all the guess work out of whether or not your in "the zone"