is basal metabolic rate?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain vital functions: breathing, heart function, body temperature, and cell renewal.
BMR accounts for 60–75% of all calories burned per day. This means that even lying in bed all day, your body burns more calories than during any workout. That is why metabolic rate is so important for weight control.
🧮 How to Calculate BMR? Mifflin-St Jeor Formula
The Mifflin-St Jeor formula (1990) is considered the most accurate modern formula for calculating BMR, especially for people with excess weight:
For Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Example for a man: 80 kg, 180 cm, 30 years → BMR = (10×80) + (6.25×180) − (5×30) + 5 = 800 + 1125 − 150 + 5 = 1780 kcal
Example for a woman: 65 kg, 165 cm, 30 years → BMR = (10×65) + (6.25×165) − (5×30) − 161 = 650 + 1031.25 − 150 − 161 = 1370 kcal
📊 What Determines BMR?
Basal metabolic rate depends on many factors — some are unchangeable, while others can be influenced:
| Factor | Effect on BMR | Can It Be Changed? |
|---|---|---|
| Muscle mass | The biggest factor. The more muscle, the higher the BMR | ✅ Yes |
| Age | BMR decreases by ~1–2% per decade after age 20. | ❌ No |
| Sex | Men have ~10–15% higher BMR (more muscle) | ❌ No |
| Body size | A larger body requires more energy | Partially |
| Genetics | Can differ by up to 200–300 kcal between people with a similar build | ❌ No |
| Hormones | Thyroid hormones directly regulate BMR | ✅ Medically |
| Body temperature | Each +0.5°C raises BMR by ~7% | ❌ No |
| Nutritional status | A long-term deficit reduces BMR by 15–30% | ✅ Yes |
🚀 How to Increase BMR?
- Increase muscle mass. Each kg of muscle burns ~13–15 kcal per day at rest. 5 kg of muscle = +65–75 kcal per day = +2 370 kcal per month.
- Eat enough protein. Protein digestion burns 20–30% of its calories (thermic effect), carbohydrates — 5–10%, fats — 0–3%.
- Do not follow long-term very low-calorie diets. Metabolism adapts — after 3–4 months of deficit, BMR can decrease noticeably.
- Be active throughout the day. NEAT (Non-Exercise Activity Thermogenesis) — walking, standing, moving — can differ by up to 2000 kcal between a sedentary and an active lifestyle.
- Consider caffeine and green tea. They temporarily (for 2-4 hours) increase BMR.
- Drink cold water. The body has to warm the water to body temperature — this requires energy.
💡 Practical Everyday Tips
📋 Track Progress
Use a diary or app. Weekly trends are more important than daily fluctuations. Regularly measure not only weight but also circumferences.
💧 Drink Enough Water
2–3 liters per day. Water aids digestion and metabolism and reduces false hunger.
😴 Sleep 7–9 Hours
Quality sleep is essential for hormonal balance, muscle recovery, and appetite control.
🏃 Move Every Day
Even 30 minutes of walking per day can significantly improve metabolism and mood.