BMR: your body at rest.

Even on a quiet day, your body has work to do. Your heart keeps beating. You keep breathing. Cells maintain and repair themselves. A workout is only one part of the energy your body uses.

01What does BMR mean?

Basal metabolic rate, or BMR, describes energy use under tightly controlled resting conditions: awake, fasted and at a comfortable temperature. Resting metabolic rate (RMR) is measured under less strict conditions and is usually a little higher. They are related measurements, rather than interchangeable terms. [1]

02Where the day’s energy goes

Total daily energy expenditure includes resting energy use, digesting and processing food, and physical activity. That last category includes everyday movement as well as exercise. Resting energy expenditure typically makes up around 60–70% of the daily total. Your personal share varies, especially with how active you are. It is not a fixed split for everybody. [1]

Think about an ordinary day: sleeping, making breakfast, walking to the shops, sitting at a desk. Some energy use continues throughout. Movement adds another part. A watch’s exercise number cannot describe the whole day.

03Does more muscle help at rest?

Muscle tissue needs energy even when it is not exercising. More muscle can therefore contribute to higher resting energy use. The size of that contribution matters: a widely used adult tissue model estimates about 13 kcal per kilogram of skeletal muscle per day at rest. This is a tissue-level estimate, not a prediction of an individual’s response to training. [2]

Using that estimate, an extra kilogram of muscle would contribute roughly 13 kcal a day at rest, rather than hundreds. This simple arithmetic does not account for other changes that happen during training. [2]

There is no need to turn strength into a promise of effortless weight loss. It can be worth practising without expecting a dramatic change in a calorie number.

04Strength can sit alongside your walks

WHO recommends that adults include activities that strengthen all major muscle groups on at least two days a week, alongside aerobic activity. Its guidance links strength activity with benefits beyond energy expenditure. [3]

That leaves room for an ordinary routine. Keep a walk you enjoy. Make space to learn strength movements with guidance appropriate to you. Start with what you can repeat, rather than trying to earn a larger calorie allowance.

Rest is part of being alive. Your body is still working.

05A number is not an eating plan

A BMR estimate does not include your full day’s needs. It should not be treated as a personal calorie target. Equations are estimates, and body composition is only one influence on resting energy expenditure. [1]

If you need an eating plan for a health condition or a specific goal, discuss your situation with a qualified professional. This article offers a way to understand energy use, without asking you to track every part of your day.

06Sources and further reading

1. National Academies, Dietary Reference Intakes for Energy (2023): Factors Affecting Energy Expenditure and Requirements. Definitions, daily expenditure and the typical resting share.
2. Wang and colleagues (2010): Specific metabolic rates of major organs and tissues across adulthood. An evaluation of tissue-level estimates, including skeletal muscle.
3. WHO Guidelines on Physical Activity and Sedentary Behaviour (2020): Recommendations. Adult aerobic and muscle-strengthening guidance.

General information, not an individual nutrition or exercise prescription. Sources checked 12 October 2026.