Health Information

The amount of energy required for any individual varies directly with the degree of activity and environmental conditions, but the rate of energy production in an individual by its over-all cellular metabolism is more or less constant under some standard conditions “basal conditions” and is known as “basal metabolism”.

The basal conditions are as follows:
1. Person should be awake but at complete rest both physical and mental.
2. Person should be without food at least 12 to 18 hrs, i.e. in the “post absorptive state”.
Post absorptive state: This period is allowed to pass for avoiding:
• Effects of digestion and absorption,
• The effects of SDA of food stuffs and
• Also to prevent any chance of starvation.
3. Should be in recumbent/ reclining position in bed.
4. Person should remain in normal condition of environment, i.e. at normal temperature, pressure and humidity (environmental temperature of between 20° to 25°C).

Under above conditions energy output of the individual is to maintain respiration, circulation, muscle tone (skeletal and smooth muscles), functions of visceras like the kidney, liver and brain for the maintenance of the body temperature.

BMR

The rate of energy production under such basal conditions per unit time (one hour) and per sq meter of body surface is known as “basal metabolic rate” (BMR).

Definition: The BMR may be defined as the amount of heat given out by a subject who though awake is lying in a state of maximum physical and mental rest under comfortable conditions of temperature, pressure and humidity, 12 to 18 hours (post absorptive) after meal.

A constant ratio of endogenous carbohydrates, lipids and proteins are metabolized under such basal conditions. Under such conditions RQ is 0.82 and each litre of oxygen consumed represents 4.825 C of energy output.