Basal Metabolism and How It Is Measured

By Dan Carey, Phd., Health & Human Performance, Univ. of St. Thomas

[this is the first in a series of posts that will look at VO2 max, anaerobic threshold, and measuring anaerobic threshold}

Basal metabolic rate (BMR) is the rate the body uses energy at rest and is expressed in calories/day. This is measured in a clinic or exercise physiology lab by measuring oxygen use by the body, with each liter of oxygen consumed being equivalent to approximately 5 calories. This is an especially important measurement for individuals trying to balance energy intake with energy expenditure and control their weight. For the average person, BMR accounts for 65-70% of daily energy expenditure.

While BMR tests are relatively inexpensive, BMR can be predicted with a fair degree of accuracy (150-200 calories) by regression equations. The best-known equation is the Harris-Benedict equation below:

BMR= 655+ 9.5(kg BW) + 1.9 (ht cm) - 4.7 age

Another simpler equation is:

Male BMR= 1.0(kg BW) times 24
Female BMR= 0.9(kg BW) times 24


For weight control it is generally recommended that an individual burns 1.75 times their BMR over the course of a day. For example, a 170-pound male (77.3 kg) would have an approximate BMR of 1855 calories/day. If this BMR is multiplied by 1.75, a value of 3245 calories/day should be expended to control body weight. Of course, the other side of the energy balance equation is energy intake. Clearly, if an individual is meeting the guidelines for energy expenditure but is exceeding this energy expenditure rate for energy intake, weight would be expected to increase.