Basal Metabolic Rate Calculation Formula | Factors Affecting Metabolic Rate

Lets know about, what is Basal Metabolic? Basal Metabolic Rate, Factors Affecting Metabolic Rate and Basal Metabolic Rate Calculation Formula.

Basal Metabolic Rate Calculation Formula | Factors Affecting Metabolic Rate
Basal Metabolic Rate Calculation Formula | Factors Affecting Metabolic Rate

What is Basal Metabolic? In a completely relaxed state of mind and body and at least 12 hours after taking food, i.e. after complete absorption of food, the total metabolic changes taking place in the body are called basal metabolism, i.e. the only vital activity of the body for survival. For example, minimum energy is required to maintain respiration, heart beat and circulation etc., to produce which body tissues require minimum oxygen. A healthy person needs 1500 to 1800 calories of energy per day to survive. is required

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Basal Metabolic Rate

The total energy used by the body to maintain the minimum normal functions of the body cells is called metabolic rate because the metabolic rate keeps changing due to many factors in humans. Therefore, the metabolic rate of a person is measured in basal conditions. The speed of energy generation in these basal conditions is called basal metabolic rate. This can usually be expressed in calories per hour per square meter of body surface area.

Basal Metabolic Rate Calculation Formula

Basal metabolic rate can be calculated through the formula given below. 

Male: 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)

Factors Affecting Metabolic Rate

Body Surface Area

On average, the surface area of the body of women is less than that of men, hence it is more in men than in women.


Metabolism gradually decreases with increasing age. Generally this rate is higher in children than in adults because children require more energy during their growth. This rate is increased in pregnant or lactating women. .

Physical exertion 

People who work Physical hard have an increased metabolic rate compared to people who do mental work while resting or sitting.


Excitable people have higher metabolic rate than calm natured people. In case of mental stress, metabolic rate increases due to increase in respiration and heart rate.


Metabolic rate increases even during high tide


The energy used in digesting food is called the specific metabolic rate of food. Consuming protein rich foods increases the metabolic rate as compared to consuming carbohydrate or fat rich foods.


Metabolic rate decreases during fasting.


Some hormones help in maintaining the metabolic rate through a feed-back system, such as when the metabolic rate is slow, the secretion of hormones called epinephrine and thyroxine increases. Thyroxine is secreted from the thyroid gland, which is more metabolic than any other hormone. When the source of thyroxine hormone increases, it is called hyperthyroidism, which increases the metabolic rate up to 100 percent of normal. Due to which there is a possibility of ophthalmic goiter and the source of thyroxine decreases, then it is called hypothyroidism. If the metabolic rate is less than the same by 40%, then there is a risk of myxedema.

The metabolic rate also increases due to anxiety and decreases in the case of depression. In case of fear or anger, the adrenal glands are stimulated to produce additional epinephrine hormone, due to which the metabolic rate increases. The metabolic rate increases due to growth hormones or sex hormones. Apart from this, other factors like climate and location can also affect the metabolic rate in species.

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Calorie Value of food

The value of a revered substance is measured by the amount of energy or power it produces when it is oxidized. Calories are used to measure energy or power. A calorie is the amount of energy or power that is required to raise the temperature of 1 liter of water by 1 degree centigrade. Calorie means kilogram which is equal to 1000 calories. The calorie value of each food item is different which is is as follows.

Energy generated from one gram of protein 4 calories
Energy generated from one gram of carbohydrate 4 calories
Energy produced from one gram of fat 9 calories

Calorie Requirement

For people doing hard physical work (labourers) 3500 calories/day
For people who work while sitting 2500 calories/day
At a rest time 1800 calories/day
For bedridden patient 1200 calories/day

Conclusion: Infants and growing children require more calories than adults; these appropriate calorie requirements are only approximate. The actual calories of a person depend on his weight, age, gender, occupation, climate, health and diet etc. The calories obtained from food prevent the body from gaining weight, control the body temperature and keep it stable, along with this the cells, Keeps tissues, glands and organs functioning.