How do you log Kinect games w/out an HRM?

elvb

I play Kinect Sports almost every day. I work up a good sweat, heavy breathing, the whole nine yards. When I log it into MFP, I enter it as High Impact Aerobics and adjust the time to a little under what I actually did (to make up for the down time between games). I haven't purchased an HRM yet (hopefully soon) and I feel like I'm cheating in some way by doing this.
Should I be choosing something else instead?

I figure once I actually get an HRM I'll be able to log it manually so I won't feel so bad lol.