WE TEST FOR RESTING METABOLIC RATE “RMR” AT BIOHACKR HEALTH
How many calories do you burn at baseline? This looks at your calorie expenditure at rest, as if you were lying in bed all day. Your heart beating, your lungs breathing, your hair and fingernails growing. It is an important metric to know. If you are on a weight change journey- weight loss or weight gain- or an exercise journey, this will help you target your calorie goals.
SUMMARY: Resting Metabolic Rate is a testable level done at Biohackr Health in Palo Alto. Resting Metabolic Rate changes with lean muscle mass and diet. It is more changeable than other biometrics, and we recommend following it every 3-4 months if on a weight or exercise journey.
CAN YOU CHANGE YOUR RMR?
YES. The two biggest ways are through your lean muscle mass and calorie intake.
- Lean body mass is the single strongest predictor of RMR. You can increase muscle mass with resistance training. Skeletal muscle is metabolically active tissue. Other organs also affect metabolic rate more- liver, kidneys, heart, and brain. It is interesting but the liver and brain are only 2% of most people’s body weight but are 20% of your resting metabolic rate needs. These organs are thought to cause 75% of the differences between individuals RMR when combined with fat and fat-free mass.
- Calorie intake affects RMR. Caloric restriction and very low calorie diets can cause RMR to decrease by 7-10%. This is a common cause of weight loss stalling. Overfeeding increases RMR.
- Exercise can affect RMR decline seen with calorie restriction. Exercise must be of sufficient frequency, intensity, and duration. There is a clear effect of exercise and energy intake on RMR.
- Exercise training effects on RMR are seen more acutely (not chronic). In one example, highly trained runners who stopped daily training had changed their RMR by 7-10%.
HOW DO YOU MEASURE RMR?
RMR BREATHING TEST- INDIRECT CALORIMETRY
This is the gold standard and what we perform at Biohackr Health. For more information, please see our blogs RMR. The test is done in our Palo Alto clinic. It takes about half an hour total, and you need to prep for it- no eating, exercise, and other requirements. It is a simple test of you relaxing and breathing into a machine which measures your oxygen and carbon dioxide levels. There is a broad range based on your skeletal muscle vs fat mass, ranging usually from 1000-2000/calories. Men’s baseline needs tend to be higher. The Mayo Clinic original study in 1988 has great graphs
RMR EQUATIONS
The Mifflin-St Jeor equation is recommended as the most accurate prediction method for both normal weight and obese individuals and is within 10% for 70-80% of people. But variation can be substantial, so indirect calorimetry is preferred. (See our Biohackr RMR test above)
- Men: RMR = 9.99 × weight (kg) + 6.25 × height (cm) – 4.92 × age + 5
- Women: RMR = 9.99 × weight (kg) + 6.25 × height (cm) – 4.92 × age – 161
