Monday, April 20, 2009

15 - Basal Metabolic Rate Mcqs with notes

1q: which of the following statements is true regarding basal metabolic rate ?

a. increased in starvation
b. it is not influenced by hormonal changes
c. it is not affected by dietary changes
d. decreased by 40 % in starvation
e. it is not affected by energy expenditure

Some important points about basal metabolic rate :

1. the energy expended by an individual during resting post-absorptive state is called Basal Metabolic Rate. It represents the energy required for normal body functions .

2. in starvation it is decreased by 40 % .

3. it is influenced by hormones like thyroid hormones and catecholamines .

4. it is affected by dietary component . eg: diet containing protein increases metabolic rate than same amount of carbohydrate and fat .

5. from 50 % to 70 % of the daily energy expenditure in sedentary individuals is attributable to BMR until very old age .

Factors affecting BMR are :

1. Age : BMR is higher in children than adults. With advancing age BMR gradually falls and in neonate BMR is high .
2. Sex : women have lower BMR than male
3. Surface area : BMR is directly proportional to body surface area .
4. Exercise : increases BMR .
5. Climate : in colder climates BMR is higher than in tropical climates.
6. Nutrition : BMR decreases 20-30 % in malnutrition ,starvation, wasting disease .
7. Body temperature : BMR rises by 14 % for each Celsius degree of elevation .
8. Hormones : circulating levels of hormones secreted by thyroid ,adrenal medulla ,anterior pituitary ( eg: GH ) , male sex hormones increase BMR .
9. Emotional state : sympathetic stimulation .
10. Pregnancy , lactation
11. Race
12. Sleep , drugs , barometric pressure etc . 

Download and read this article by American journal of nutrition which discusses about the various factors affecting the BMR on priority basis.

The MCQ above was asked in the PGIMER ( PGI ) chandigarh 2001 december paper .

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