Definition
It is defined as the minimum amount of energy required by the body to maintain life at complete physical or mental rest
While determining BMR:-
1) person should awake but had sound sleep.
2) At rest
3) in a post absorptive state.
4) Not any strenous activity
5) At neutral temperature
6) Not in stress
Measurement of BMR
BMR Usually measured in the morning fasting time.
The person should be mentally relexed and comfortable seated.
BMR measured by two methods:-
1) open circuit method (Douglas Method)
2) closed circuit method (Benedict- routh Method)
Factors affecting BMR
1) Age :- The BMR in children is higher than adults.
As the person ages, the BMR decreases because the lean body mass decline with age.
2) Gender:- BMR is higher in male than in women, because of the greater lean muscles mass in the men.
3) Body surface Area:- BMR is directly proportional to the body surface area.
Increases in surface area BMR increases
4) Climate condition:- in colder climate the BMR is higher.
5) physical activity :- Athletes and leverage have high BMR compared to person who lead a senatory life
BMR is up to 50% decrease during starvation.
6) Fever :- BMR increased is about 12% with arise of 1°C a body temperature
7) Stress:- Under severe stress, major trauma BMR increases.
Normal range of BMR:-18.5-24kg
In Adult female :- 22 cal/kg bodywt/day
In Adult male :- 24cal/kg bodywt/day
Significance of BMR
1) BMR is important to calculate the calorific requirement of an individual and planning of diets.
2) Assessment of thyroid function.
3) BMR is low normal in starvation, under nutrition, Addison's disease
4) BMR is above normal in fever, diabetes insipidus, leukaemia and polycythemia.
