My son is doing his science project on the impact of the battery of your heart rate and compares it works as an aerobic workout. I fear that the movement of arms and drums with the precision of a clock type monitor heart rate would stören.Auch that this science for a project and probably will not be used again, I do not want to spend too much money for monitors, but I’m available online seem to need expensive equipment properly arbeiten.Irgendwelche suggestions?