Three equations were derived to predict the energy expenditure of adult males walking on the treadmill. The estimation from walking speed is the most satisfactory with a mean deviation of 0.73% (SD=±8.97%) from values actually observed ; the equation is

E/BW = 0.0006732V^2 - 0.0549V + 3.42

where E, BW and V stand for energy expenditure (kcal/hr), body weight (kg) and walking speed (m/min), respectively. Other two equations in terms of heart rate are as follows :

E/BW=6.39W/R-4.15

E/BW=7.08R1/R-4.78

where R, W and R1 are heart rates expressed in beats/min before walk, during walk and for the first 30 sec after walk, respectively. The mean variability of the values obtained from the equations is within 4% of those actually observed. By using the last equation, the energy expenditure can be easily predicted without measuring the walking spped and the heart rate during walk, although the accuracy of the prediction is a little inferior to the other equations. ' Based on these prediction equations, three nomograms were developed not only to predict the energy expenditure of walking but aiso to preset the treadmill spped to obtain a given energy expenditure.