The Schofield equation is the name of a formula used to calculate an individual's basal metabolic rate (BMR). Basal metabolism is the amount of energy a body needs to use to sustain life. Energy is needed for metabolism at the cellular level, synthesis of hormones and enzymes, temperature maintenance, muscle movement and more. The BMR measures the basal metabolism over a given period of time, usually over the course of 24 hours. The Schofield equation is actually one of a set of equations that calculates minimal daily caloric needs to avoid weight loss based upon an individual's age group and sex.
The BMR represents 45 to 70 percent of calories burned during the day. The large disparity in this percentage is secondary to the enormous variability of the BMR depending upon age, sex and physical activity. The remaining percentage of calories utilized relies primarily upon the degree of physical activity expended by a given individual. For sedentary individuals who engage in little physical activity, the BMR will represent a higher percentage of calories burned. Physically active teenage boys, on the other hand, will have a BMR representing a smaller percentage of their daily caloric expenditures.
Internet calculators are available to perform Schofield equations. A table, however, is the easiest way to identify how an individual's age and sex influence the appropriate Schofield equation necessary to determine the basal metabolic rate. As indicated in the table below, men have a higher overall BMR than women and younger individuals have higher BMRs than do their elders. The larger than expected constant of 14.8 under the female column for those aged 18 to 30 represents the higher caloric expenditures typical of pregnancy and lactation. The overall greater BMR of men over that of women is attributed to their body composition: men have a larger ratio of muscle to fat, in addition to their typically greater amount of physical activity.
|AGE (in years)||MALE||FEMALE|
|15-18||BMR = 17.6 x kg weight + 656||BMR = 13.3 x kg weight + 690|
|19-30||BMR = 15.0 x kg weight + 690||BMR = 14.8 x kg weight + 485|
|31-60||BMR = 11.4 x kg weight + 870||BMR = 8.1 x kg weight + 842|
|>60||BMR = 11.7 x kg weight + 585||BMR = 9.0 x kg weight + 656|