We recommend consulting a qualified physician before making any changes to your lifestyle.
What is Basal Metabolic Rate (BMR)?
Basal Metabolic Rate (BMR) is the amount of energy your body uses each day at rest, without considering any physical activity. Essentially, it represents the energy required to keep you alive and your organs functioning, even if you spend the day in bed and do not move any muscles.
Our BMR calculator uses two formulas for calculation:
1. Basal Metabolic Rate Formula:
This formula takes your height, weight, and age as input and provides a number representing the energy your body needs while at rest.
2. Harris-Benedict Formula:
We use the original Harris-Benedict formula to estimate your body’s energy requirements based on your activity level.
Using these formulas, our calculator provides an approximate daily BMR. However, keep in mind that lean body mass, an important factor, is not considered here.
For example, it may underestimate the energy needs of very muscular individuals or overestimate the energy needs of very obese individuals.
Factors Affecting BMR
Muscle Mass
Aerobic exercises such as running or cycling do not significantly affect BMR. However, anaerobic exercises, like weight training, indirectly increase BMR by building muscle, which raises energy expenditure at rest. The more muscle mass a person has, the higher their basal metabolic rate.
Age
As a person ages and becomes less active, their BMR—or the energy needed to maintain vital organ function—gradually decreases.
Genetics
Certain inherited traits from parents also play a role in determining an individual’s precise BMR.
Climate
Cold weather increases BMR because the body burns energy to stay warm. Extremely hot climates also raise energy expenditure, as the body requires energy to cool internal organs. Approximately, for every 1.36°F change in temperature, your body’s BMR adjusts by about 7%.
Diet
Eating multiple small meals throughout the day can increase BMR. Conversely, prolonged fasting can reduce your BMR by up to 30%. Similar to a smartphone switching to low-power mode when the battery is low, the human body responds to low energy levels with decreased activity, reduced mental function, and lower energy expenditure.
Pregnancy
Supporting the growth and nutrition of a fetus increases a mother’s BMR. This is why pregnant women often experience increased appetite. Similarly, hormonal changes during menopause can either raise or lower BMR, depending on the individual.
Dietary Supplements
Some supplements or medications, often intended for weight loss, can raise BMR. Caffeine is one of the most common examples.