It is better to consult a certified specialist or measure BMR through a calorimetry device. Online BMR tests with rigid formulas are not the most accurate method of determining an individual's BMR. Supplements – Certain supplements or drugs raise BMR, mostly to fuel weight loss. Also, menopause can increase or decrease BMR depending on hormonal changes. This is why pregnant women tend to eat more than usual. Pregnancy – Ensuring the livelihood of a separate fetus internally increases BMR. Similar to a phone that goes into power-saving mode during the last 5% of its battery, a human body will make sacrifices such as energy levels, moods, upkeep of bodily physique, and brain functions in order to more efficiently utilize what little caloric energy is being used to sustain it. On the other hand, starvation can reduce BMR by as much as 30%. BMR increases approximately 7% for every increase of 1.36 degrees Fahrenheit in the body's internal temperature.ĭiet – Small, routinely dispersed meals increase BMR. Likewise, too much external heat can raise BMR as the body expends energy to cool off internal organs. Weather – Cold environments raise BMR because of the energy required to create a homeostatic body temperature. Genetics – Hereditary traits passed down from ancestors influence BMR. The more muscle mass in the physical composition of an individual, the higher the BMR required to sustain their body at a certain level.Īge – The more elderly and limber an individual, the lower their BMR, or the lower the minimum caloric intake required to sustain the functioning of their organs at a certain level. However, anaerobic exercises, such as weight-lifting, indirectly lead to a higher BMR because they build muscle mass, increasing resting energy consumption. Muscle Mass – Aerobic exercises, such as running or cycling, have no effect on BMR. The three equations used by the calculator are listed below: You can pick the equation to be used in the calculation by expanding the settings. Of these equations, the Mifflin-St Jeor Equation is considered the most accurate equation for calculating BMR with the exception that the Katch-McArdle Formula can be more accurate for people who are leaner and know their body fat percentage. The Katch-McArdle Formula is slightly different in that it calculates resting daily energy expenditure (RDEE), which takes lean body mass into account, something that neither the Mifflin-St Jeor nor the Harris-Benedict Equation does. The Mifflin-St Jeor Equation has been shown to be more accurate than the revised Harris-Benedict Equation. It was revised in 1984 to be more accurate and was used up until 1990, when the Mifflin-St Jeor Equation was introduced. The Harris-Benedict Equation was one of the earliest equations introduced. In most situations, the BMR is estimated with equations summarized from statistical data. The daily caloric need is the BMR value multiplied by a factor with a value between 1.2 and 1.9, depending on activity level. Basal metabolism is usually the largest component of a person's total caloric needs. An accurate BMR measurement requires that a person's sympathetic nervous system is inactive, which means the person must be completely rested. The BMR is measured under very restrictive circumstances while awake. Physical activity makes up ~20% of expenditure and ~10% is used for the digestion of food, also known as thermogenesis. For most people, upwards of ~70% of total energy (calories) burned each day is due to upkeep. In such a state, energy will be used only to maintain vital organs, which include the heart, lungs, kidneys, nervous system, intestines, liver, lungs, sex organs, muscles, and skin. It is the equivalent of figuring out how much gas an idle car consumes while parked. The basal metabolic rate (BMR) is the amount of energy needed while resting in a temperate environment when the digestive system is inactive. Related Body Fat Calculator | Calorie Calculator

Bmr calculator with body fat