Determination of Basal Metabolism

Determination of Basal Metabolism
  • The amount of energy required to carry on the involuntary work of the body is known as basal metabolic rate.
  • Basal metabolism is usually determined using the apparatus called Benedict and Roth Apparatus.
  • The apparatus is a closed circuit system in which the subject breathes in oxygen from a metal cylinder of about 6-litre capacity and CO2 produced is absorbed by soda-lime present in the tower.
  • The oxygen cylinder floats on water present in an outer tank.
  • The subject wears a nose clip and breathes through a mouthpiece the oxygen present in the cylinder for a period of 6 minutes.
  • The volume of O2 used is recorded on a graph paper attached to a revolving drum by a pen attached to it.
  • Since the subject is in the post-absorptive state, R.Q. is assumed to be 0.82 and the calorific value of one litre of O2 consumed is taken as 4.8 Kcal.
Benedict and Roth Apparatus

Subject: Adult male, 50 kg body weight.
Oxygen consumed in 6 minutes = 1,100 ml
Heat produced in 6 minutes = 4.8 x 1.1 = 5.28 Kcal
Heat produced in 24 hours = 5.2 x 10 x 24 = 1,267 Kcal
The basal metabolism of an individual for 24 hours = 1,264 Kcal.

Last modified: Monday, 4 June 2012, 4:27 AM