Basal Metabolic Rate

What Is Basal Metabolic Rate?

You burn calories even when resting through basic life-sustaining functions like breathing, circulation, nutrient processing, and cell production. This is known as basal metabolic rate (BMR).

Basal metabolic rate (BMR) vs resting metabolic rate (RMR)

Basal metabolic rate (BMR) is often used interchangeably with resting metabolic rate (RMR).

While BMR is the minimum number of calories required for basic functions at rest, RMR — also called resting energy expenditure (REE) — is the number of calories that your body actually burns while it’s at rest.

Although BMR and RMR slightly differ, your RMR should be an accurate estimate of your BMR. The two values tend to vary by about 10% Trusted Source

How to estimate your BMR

One popular way to estimate Trusted Source BMR is through the Harris-Benedict formula, which takes into account weight, height, age, and sex.

Females assigned at birth (FAABs)

BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in years)

Males assigned at birth (MAABs)

66 + (13.7 x weight in kg) + (5 x height in cm) – (6.8 x age in years)

How many calories do you need every day?

If you want to get an idea of how many calories you should eat daily and you’ve estimated your BMR using the Harris-Benedict formula, your next step is to include the number of calories you burn during daily activities based on your lifestyle:

• Sedentary: If you get minimal or no exercise, multiply your BMR by 1.2.
• Lightly active: If you exercise lightly one to three days a week, multiply your BMR by 1.375.
• Moderately active: If you exercise moderately three to five days a week, multiply your BMR by 1.55.
• Very active: If you engage in hard exercise six to seven days a week, multiply your BMR by 1.725.
• Extra active: If you engage in very hard exercise six to seven days a week or have a physical job, multiply your BMR by 1.9.

The final number is approximately how many calories you need on a daily basis to maintain your weight.

Of course, this is an estimate. According to a 2021 study, the formula would be more accurate if it included body composition, weight history, and other factors that have been shown to affect BMR.

However, to get the most accurate idea is to have a trained technician perform indirect calorimetry, which is a study of your metabolism. This test measures how much oxygen (O2) you take in and how much carbon dioxide (CO2) you take out when you breathe. The quantity of these gases variesTrusted Source depending on how your body metabolizes different macronutrients such as carbs, fats, and protein for energy.

How you can change your BMR 

Your BMR is determined by a number of factors, including:

• sex
• weight
• height
• age
• ethnicity
• weight history
• body composition
• genetic factors

Of these factors, you can take steps to change your weight and body composition. So if you want to change your BMR, your first step should be to increase muscle.

For example, a 2018 study suggests that resistance training is an effective means of boosting BMR levels among a group of inactive adult women. However, this won’t necessarily translate to weight loss, according to the researchers.

Tips to Improve Health

• Exercise Regularly: Combine cardiovascular exercises (like walking or running) with strength training to boost metabolism.
• Healthy Diet: Focus on balanced meals that include lean proteins, whole grains, vegetables, and healthy fats.
• Stay Hydrated: Drink enough water daily, as hydration affects metabolism.
• Quality Sleep: Aim for 7–9 hours of sleep per night to support metabolic health.
• Manage Stress: High-stress levels can negatively impact metabolism.