Comment Be thankful your PE teacher is making the effort. (Score 1) 950
As mentioned in some of the other replies, monitoring based on heart rate is the goal.
If you want the reasoning behind it read this book:
Spark ( http://www.amazon.com/Spark-Revolutionary-Science-Exercise-Brain/dp/0316113506 )
- Quick Summary: Exercise is f'ing awesome for the brain, and you learn better if you exercise (especially in the morning)
I wish I had been taught PE with a heart rate monitor in school.