Learning to exercise and keep yourself in shape is a part of the cirriculum.
Start looking up child obesity numbers and you'll see that schools need to be doing more, not less.
I'd imagine the program is to let kids know where their heart rates are, and where they should be to get good exercise. Even if they are recording everything, it's pretty meaningless information. You'd know a person's heart rate from 7th grade.
The bigger issue here is whether your kids are getting exercise and whether they're overweight. If they're heavy, do everything possible to encourage exercise. Once the habits are set, they're incredibly difficult to change once they're adults.