During one of the rounds at the Eagle Peak Open I wore my wife's fancy new heart rate monitor with GPS.
Once the data was downloaded, there was a lot of information on the how much energy it took to play the temp 13 holes that the Rebels set up at Willamette Pass.
Turns out I used up over 1100 calories and actually climbed 2400 feet while descending 3800 feet. You can check out the results here
Amazing how accurate the GPS was. Zoom in with the satellite picture turned on and you can see pretty much ever move I made.
I'll probably use one at Lava Launch and compare the results.