A person burns calories continuously throughout the day to maintain basic functions of life, such as breathing, circulation, and digestion. Basal metabolic rate is an approximate minimum number of calories a person needs each day to maintain these functions at rest.
What is Basal Metabolic Rate?
The basal metabolic rate (BMR) estimates the minimum number of calories a person needs to burn to maintain the basic functioning of his life during a 24-hour rest period. Examples of such functions include:
- Blood circulation
- Digestion and absorption of nutrients
- Cellular process.
Basal Metabolic Rate is expressed in Kg weight. This number differs between people and perhaps in the same person when there is a change in physical and environmental circumstances. Basal metabolism is an oxygen-carrying metaloprotein containing iron in red cells in the blood of mammals and other animals.
Basal metabolism is a protein rich in iron. It has an affinity (combined power) to oxygen and with oxygen it forms energy inside red blood cells. Through this function, oxygen is carried from the lungs to the tissues (Evelyn, 2009).
Basal metabolism can be measured scientifically and the amount of BW/65 kg can be used as an index of oxygen carrying capacity in energy.
The pacemaker membrane theory says that the composition of fatty acids in the double membrane of phospholipids is a very important stain of BMR. This theory was triggered after it was discovered that the high ratio of docosahexaenoic acid in the phospholipid bilayer acyl groups triggered high metabolic activity in the cell membrane.
The secretion and production of thyroid hormones in mammals communicate with body weight, although figures show the second relationship has not yet been decided. Along with the development of weight and decreased ratio of BMR: weight, polyunsaturated membrane will decrease while monounsaturated membrane will increase.
Cells with membrane composition containing poly-saturated fatty acids (PUFA) are considered to be shorter in life, and more responsive to surrounding stimulation, compared to saturated fatty acids (SFA) and mono-unsaturated fatty acids (MUFA).
Basal metabolic rate Vs resting metabolic rate
People often use the terms BMR and RMR in turn. However, the two tests differ slightly in terms of estimation and testing.
BMR estimates the minimum number of calories a person needs each day to maintain the basic functions of his or her life if they rest for 24 hours a day. However, to obtain an accurate estimate, one must undergo clinical monitoring under strictly controlled conditions. These include:
- Fasting for 12 hours before the test
- Sleep for 8 hours before testing, when waking up
- Undergoing monitoring in a dark room with a controlled temperature
- Testing in lying position.
RMR estimates the number of calories a person burns during a period of inactivity. People do not need to fast or rest for long in a controlled environment to get an estimate. Since RMR measurement testing conditions are less stringent than those required to measure BMR, RMR may be slightly less accurate than the BMR.
How to Calculate Basal Metabolic Rate
If you want to lose weight, it’s a good idea to calculate your BMR. You can find the number using a formula designed by scientists, you can test it in a laboratory, or you can use an online calculator. There is no highly accurate method, but a lab test will probably give you the best estimate.
But because laboratory tests can be expensive, many dieters and exercise players use one of two other methods to determine basal metabolic rate and/or the total number of calories they burn each day.
Formula to figure out your BMR
The Harris-Benedict equation is often used to estimate basal metabolic rates.
Men: BMR = 88,362 + (13,397 x weight in kg) + (4,799 x height in cm) – (5,677 x age in years)
Women: BMR = 447,593 + (9,247 x weight in kg) + (3,098 x height in cm) – (4,330 x age in years).