DU BOIS: BASAL ENERGY REQUIREMENT OF MAN 353 



tunately, not accurate. Recently a better method was devised 

 by Mr. Delafield Du Bois. This so-called height-weight formula 

 can be expressed in a chart which enables one to find the approxi- 

 mate surface area if the height and weight of the individual be 

 known. Using it to recalculate the results obtained upon nor- 

 mal persons, we find that the average heat production of men 

 between the ages of twenty and fifty is about 40 calories per 

 square meter per hour. There is a normal range of variation 

 amounting to plus or minus 10 per cent from the average, and 

 a few apparently normal individuals may depart as much as 15 

 per cent from the mean. Curiously enough very fat people and 

 very thin ones have almost exactly the same heat production, 

 measured in this way, while there may be a difference of 30 or 

 40 per cent between the two groups if we base the calculations 

 on kilograms of body weight. 



The level of the metabolism varies greatly with age. During 

 the first few days of life it is very low, then rises rapidly during 

 infancy, and reaches its highest level in the almost unexplored 

 period between the ages of two and six years. After this it falls 

 rapidly until about the eighteenth year when the curve flattens 

 out. Between the ages of twenty and forty there is compara- 

 tively little change, but after this a slight fall, so that by the 

 eightieth year the line is about 10 per cent below the average 

 level for the ages of twenty to forty. There seems to be a stimu- 

 lation to the basal metabolism during the period of growth. 



Women show an average basal metabolism about 7 per cent 

 lower than that of men of the same age. Athletes are about 7 

 per cent higher than men of sedentary habits. Confinement in- 

 doors or in bed reduces the metabolism, as does cage life for a 

 previously active dog. Prolonged undernutrition can reduce 

 the metabolism 30 or 40 per cent. Benedict's subject Levanzin, 

 who fasted for thirty-one days, showed a marked reduction in 

 basal metabolism, amounting to about 23 per cent after three 

 weeks starvation. 



The basal metabolism is always measured fourteen hours or 

 more after the last meal, because food stimulates the heat pro- 

 duction. A meal containing 60 grams of protein can increase the 



