Basal Metabolic Rate
The amount of calories required by a human body to keep functioning while at rest is called the basal metabolic rate (BMR). So basically, you still burn calories while you are asleep.
As your body is still functioning while you are asleep, your brain is still in action, your digestive system is processing the food you had for dinner, your heart is still pumping blood, your brain is still working which is why you continue to breathe while you sleep.
But that doesn’t mean you can take BMR lightly. Basal metabolism is responsible for 60-70% of the calories that you burn throughout the day.
BMR calculator
There are a lot of BMR calculators available online. Most BMR calculators use Mifflin-St. Jeor equations. Some calculators also use the Harris-Benedict equation. But the Mifflin-St. Jeor equations are considered to be a lot more accurate than the Harris-Benedict equation.
How it works is, you enter your current height, weight, age and gender and depending on the equation used, the site’s algorithm will calculate the BMR for you. Just Google BMR calculator and you will find a lot of them on the internet.
Basal metabolic rate definition
Every human body generates heat. This phenomenon is called as thermo genesis. The amount of energy expended can be determined based on this process. As obvious as it sounds, BMR reduces with age. That is why keeping your body fit becomes important because increasing your muscle mass increases the body temperature. Factors that can affect BMR and overall energy expenditure include stress, environmental temperature, previously consumed foods and beverages, illness, etc.
If a person is awake when measuring BMR, the calculation might not really be accurate. The sympathetic nervous system shouldn’t be active while calculating BMR. Therefore, this condition requires the person to be continuously at rest. Gas analysis is used to measure the BMR. Either the direct or indirect calorimetry can be used to calculate the BMR. Or you can just use the online calculator, key in your current weight, height, and gender and get the results. Whichever method you use; it has been proven that both the methods are pretty accurate when it comes to determining the respiratory quotient.
What diet to use?
By far, the largest component of total caloric expenditure can be safely considered as the basal metabolism. However, you must be clear that the current available methods of BMR calculation are only approximations, especially those dependent on the Harris-Benedict equations. The expense of energy during thermo genesis and other physical activities make it difficult to determine the exact BMR.
Learn basal metabolism
To summarize the concept of basal metabolism, the basal functioning of the human body contributes to about 70% of energy consumption, the thermo genesis process uses about 10% and the physical activity that we do every day, takes about 20%.