| |
| Definition |
| Basal Metabolic Rate (BMR) is the minimum caloric requirement to sustain life in a resting individual. It can be responsible for burning up to 70% of total calories expended. |
| |
| BMR Factors |
- Genetics
- People are born with different metabolism speed
- Gender
- Males have more muscle mass and less body fat
- Males average 10-15% higher BMR than females.
- Age
- After 20yrs of age, BMR drops 2% per decade
- Weight
- The heavier you are, the higher your BMR
- Heavier women have 25% higher BMR than thinner women.
- Body Surface Area (BSA)
- The greater your BSA, the higher your BMR is
- Body Fat Percentage (BF%)
- A lower BF% means a higher BMR
- Diet
- Starvation and/or a Low caloric intake, can reduce your BMR from about 20-30%
- Body Temperature
- For every increase of 0.5C in internal temperature of the body, the BMR increases by about 7 percent.
- The chemical reactions in the body actually occur more quickly at higher temperatures.
- So a patient with a fever of 42C (about 4C above normal) would have an increase of about 50 percent in BMR.
- External Temperature
- Prolonged exposure to colder temperatures can increase BMR to create the extra body heat needed.
- Glands
- Thyroxin (produced by the thyroid gland) is a key BMR-regulator which speeds up the metabolic activity of the body.
- The more thyroxin produced, the higher the BMR.
- If too much thyroxin is produced (a condition known as thyrotoxicosis) BMR can actually double.
- If too little thyroxin is produced (myxoedema) BMR may shrink to 30-40 percent of normal.
- Adrenaline also increases the BMR to a lesser extent.
- Exercise
- Building lean muscle helps to burn more calories and raise your BMR
|
| |
| Measuring BMR |
- Gas Analysis through direct or indirect calorimetry
- Formulas
|
| |
| BMR Formulas |
| Click here for a list of BMR formulas |
| |
| Sources Cited |
- Expert Panel on the Identification, Evaluation and Treatment of Overweight in Adults. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: Executive Summary. Downloaded from www.ajcn.org on July 9, 2006, Am J Clin Nutr 1998; 68:899-917.
- Wikipedia
- USDHHS
- USDA
|
| |