Using the standard methods of prediction which employ one calibration point at rest and
a series of calibration points at several levels of activity, it was found that the 24 h energy
expenditure of individuals could not be predicted from HR with any acceptable extent of
accuracy. This was mainly because the relation between HR and HP was linear using the
standard calibration procedure only at energy expenditures greater than approximately
10 kJ/min. The relation seemed less close at the levels of HP or HR which are usually
encountered during a sedentary or moderately active day.