Schofield equation

The Schofield Equation is a method of estimating the basal metabolic rate (BMR) of adult men and women published in 1985.

This is the equation used by the WHO in their technical report series.World Health Organization, Fao, and Unu. Energy and protein requirements. Geneva: WHO, Technical Report Series 724, 1985. The equation that is recommended to estimate BMR by the US Academy of Nutrition and Dietetics is the Mifflin-St. Jeor equation.J Am Diet Assoc. 2009;109:330-346.

The equations for estimating BMR in kJ/day (kilojoules per day) from the body mass W (kg) are:Energy Requirements of Adults, Report of a Joint FAO/WHO/UNU Expert Consultation, (See table 5.2).

Men: Age Equation (kJ/day) SEE < 3 249 × W - 127 292 3–10 95 × W + 2110 280 10–18 74 × W + 2754 441 18–30 63 × W + 2896 641 30–60 48 × W + 3653 700 > 60 49 × W + 2459 686

Women:

Age Equation (kJ/day) SEE < 3 244 × W - 130 246 3–10 85 × W + 2033 292 10–18 56 × W + 2898 466 18–30 62 × W + 2036 497 30–60 34 × W + 3538 465 > 60 38 × W + 2755 451

The equations for estimating BMR in kcal/day (kilocalories per day) from body mass (kg) are:

Men: Age Equation (kcal/day) SEE < 3 59.512 × W - 30.4 70 3–10 22.706 × W + 504.3 67 10–18 17.686 × W + 658.2 105 18–30 15.057 × W + 692.2 153 30–60 11.472 × W + 873.1 167 > 60 11.711 × W + 587.7 164

Women: Age Equation (kcal/day) SEE < 3 58.317 × W - 31.1 59 3–10 20.315 × W + 485.9 70 10–18 13.384 × W + 692.6 111 18–30 14.818 × W + 486.6 119 30–60 8.126 × W + 845.6 111 > 60 9.082 × W + 658.5 108

Key:

W = Body weight in kilograms

SEE = Standard error of estimation

The raw figure obtained by the equation should be adjusted up or downwards, within the confidence limit suggested by the quoted estimation errors, and according to the following principles:

Subjects leaner and more muscular than usual require more energy than the average. Obese subjects require less. Patients at the young end of the age range for a given equation require more energy. Patients at the high end of the age range for a given equation require less energy.

Effects of age and body mass may cancel out: an obese 30-year-old or an athletic 60-year-old may need no adjustment from the raw figure.

Physical activity levels

To find total body energy expenditure (actual energy needed per day), the base metabolism must then be multiplied by a physical activity level factor. These are as follows:

Activity Male Female Description Sedentary 1.3 1.3 Very physically inactive, inactive in both work and leisure. Lightly active 1.6 1.5Daily routine includes some walking, or intense exercise once or twice per week. Most students are in this category. Moderate activity 1.7 1.6Intense exercise lasting 20–45 minutes at least three time per week, or a job with a lot of walking, or a moderate intensity job.Very active2.11.9Intense exercise lasting at least an hour per day, or a heavy physical job, such as a mail carrier or an athlete in training.Extremely active2.42.2Extremely active means an athlete on an unstoppable training schedule or a very demanding job, such as working in the armed forces or shoveling coal.

The FAO/WHO uses different PALs in their recommendations when recommending how to calculate TEE. See Table 5.3 of their working document. Energy Requirements of Adults, Report of a Joint FAO/WHO/UNU Expert Consultation.

These equations were published in 1989 in the dietary guidelines and formed the RDA's for a number of years. The activity factor used by the USDA was 1.6. In the UK, a lower activity factor of 1.4 is used. The equation has now been replaced by the Institute of Medicine Equation in September 2002 in the US, however is still currently used by the FAO/WHO/UNU.

Schofield equation

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