Topic:” Energy expenditure measurement methods.”
ENERGY EXPENDITURE:
The energy is involved in every aspect, movement and breadth of life. The living entity
uses energy for nourishing, developing and surviving. The energy expenditure can be
estimated by measuring macronutrient or oxygen consumption, or heat production or
carbon dioxide production. Energy expenditure is determined by body size and body
composition and by food intake and physical activity. There are a lot of ways in which
energy is being utilized by the body; including Basic Metabolic rate, Thermic effect of
food and Physical Activity. The methods which through the amount and rate of energy
expenditure can be measured includes:
1. Direct Calorimeter.
2. Indirect Calorimeter.
3. Doubly layered water technique.
These techniques help in quantifying the energy expenditure of body at rest and during
physical activity.
DIRECT CALORIMETER:
Principle:
The result of all metabolic processes produces combustion. In the 1770’s the French
Chemist Antoine, and his companions provided the impetus to directly measure the
energy expenditure at rest and physical state of work. The bomb calorimeter represents
the same idea, the measurement of heat production in human bodies.
Figure 1.1 Diagrammatic representation
of bomb calorimeter.
Working:
1
, The human calorimeter consists of a chamber where a human being lives or a selected
time span. At the top of chamber, the measured amount of water circulates through coils
at a specific set temperature. The water absorbs the heat produced and radiated by the
individual in the chamber. The layer of insulation provides regulation, so any change in
the temperature of water directly represents the heat production by the individual. The
ventilation system is maintained by the exhaled air of the individual continually passes
from the room that passes through the chemicals and removes the moisture and absorb
carbon dioxide. Oxygen is added to the air that recirculated through the chamber.
Figure 1.2 Pictorial representation of human calorimeter.
Mechanism:
In Atwater-Rosa Calorimeter- a thin copper sheet lines through which the heat exchanges
and water passes through it. The water temperature when cooled to 2 degree C, the water
flows more rapidly. Rapidly flowing water absorbs the heat produced from the subject
performing exercise. As the subject slows down, the rate of water also slows down.
2
ENERGY EXPENDITURE:
The energy is involved in every aspect, movement and breadth of life. The living entity
uses energy for nourishing, developing and surviving. The energy expenditure can be
estimated by measuring macronutrient or oxygen consumption, or heat production or
carbon dioxide production. Energy expenditure is determined by body size and body
composition and by food intake and physical activity. There are a lot of ways in which
energy is being utilized by the body; including Basic Metabolic rate, Thermic effect of
food and Physical Activity. The methods which through the amount and rate of energy
expenditure can be measured includes:
1. Direct Calorimeter.
2. Indirect Calorimeter.
3. Doubly layered water technique.
These techniques help in quantifying the energy expenditure of body at rest and during
physical activity.
DIRECT CALORIMETER:
Principle:
The result of all metabolic processes produces combustion. In the 1770’s the French
Chemist Antoine, and his companions provided the impetus to directly measure the
energy expenditure at rest and physical state of work. The bomb calorimeter represents
the same idea, the measurement of heat production in human bodies.
Figure 1.1 Diagrammatic representation
of bomb calorimeter.
Working:
1
, The human calorimeter consists of a chamber where a human being lives or a selected
time span. At the top of chamber, the measured amount of water circulates through coils
at a specific set temperature. The water absorbs the heat produced and radiated by the
individual in the chamber. The layer of insulation provides regulation, so any change in
the temperature of water directly represents the heat production by the individual. The
ventilation system is maintained by the exhaled air of the individual continually passes
from the room that passes through the chemicals and removes the moisture and absorb
carbon dioxide. Oxygen is added to the air that recirculated through the chamber.
Figure 1.2 Pictorial representation of human calorimeter.
Mechanism:
In Atwater-Rosa Calorimeter- a thin copper sheet lines through which the heat exchanges
and water passes through it. The water temperature when cooled to 2 degree C, the water
flows more rapidly. Rapidly flowing water absorbs the heat produced from the subject
performing exercise. As the subject slows down, the rate of water also slows down.
2
