<!-- Do not copy any part of this script without permission; James T. Griffing, MS, BS; http://www.exrx.net //--><!-- 
function calc (form) {
var MHR, LHR, HHR, PMeth, RMeth
LHR = form.LowHR.value / 100
HHR = form.HighHR.value / 100
  if (form.Age.value < 110) {
     MHR = 220 - form.Age.value
     PMeth = "Percent of Age Predicted "
}
  if (form.Age.value >= 110) {
     MHR = form.Age.value
     PMeth = "Percent of "
}
  if (form.RHR.value > 0) {
     form.LowBPM.value = (MHR - form.RHR.value) * LHR + form.RHR.value * 1
     form.HighBPM.value = (MHR - form.RHR.value) * HHR + form.RHR.value * 1
     RMeth = "Heart Rate Reserve"
}
  else {
     form.LowBPM.value = MHR * LHR
     form.HighBPM.value = MHR * HHR
     RMeth = "Maximum Heart Rate"
}
form.Method.value = PMeth + RMeth
}
//-->