Notesale: Turn your study into money

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Topic:” Energy expenditure measurement methods
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The living entity
uses energy for nourishing, developing and surviving
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Energy expenditure is determined by body size and body
composition and by food intake and physical activity
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The methods which through the amount and rate of energy
expenditure can be measured includes:
1
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2
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3
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These techniques help in quantifying the energy expenditure of body at rest and during
physical activity
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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
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Figure 1
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Working:
1

The human calorimeter consists of a chamber where a human being lives or a selected time
span
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The water absorbs the heat produced and radiated by the
individual in the chamber
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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
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Figure 1
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Mechanism:
In Atwater-Rosa Calorimeter- a thin copper sheet lines through which the heat exchanges
and water passes through it
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Rapidly flowing water absorbs the heat produced from the subject
performing exercise
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2

The rear wheel of the bicycle contacts the shaft of the generator and then lights the bulb
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The wheel is being rotated in
the field of an electromagnet, producing an electric current for accurately determining
output power
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The use of calorimeter remains inapplicable for energy
determinations for most sport, occupational and recreational activities
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INDIRECT CALORIMETER:
All energy releasing reactions in the body ultimately depend on oxygen use
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Caloric transformation of Oxygen:
Working principle:
The case studies has revealed that the bomb calorimeter shows that 4
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There, can be large
variations in the metabolic mixture, but the calorific value of oxygen varies slightly 2-4%
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0 Kcal of energy released by oxygen for a mixed diet, which is designated as
appropriate conversion factor for estimating energy expenditure under steady-rate
conditions of aerobic metabolism
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0 Kcal per liter provides a convenient yardstick for
transposing any aerobic physical activity to a caloric frame of reference
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Working mechanism:
The subject inhales the 100 % oxygen from a spirometry
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A canister of soda lime
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(potassium hydroxide) in the breathing circuit absorbs the carbon dioxide in the exhaled air
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It is difficult to measure oxygen uptake during exercise in a closed
circuit spectrometry
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Figure 1
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Open-circuit spirometry:
Working Mechanism:
An open-circuit spirometry, a subject inhales ambient air with a constant composition of
20
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03% carbon dioxide, and 79
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The nitrogen fraction also
Include a small quantity of inert gases
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Thus, analysis of two factors—volume of air breathed during a specified time period and
composition of exhaled air—provides a useful way to measure oxygen uptake and infer
energy expenditure
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Portable spirometry
2
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Computerized instrumentation
4
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The subject carried like a backpack
the 3-kg box-shaped apparatus
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The meter measured total expired air volume
and collected a small gas sample for later analysis of oxygen and carbon dioxide content
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The equipment becomes cumbersome during vigorous activity
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Figure 1
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Bag Technique:
A subject rides a stationary bicycle ergometer, wearing headgear containing
A two-way, high-velocity, low-resistance breathing valve
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The air then passes into either large
canvas or plastic Douglas bags (named for distinguished British respiratory
physiologist Claude G
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The meter
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collects a small sample of expired air for analysis of oxygen and carbon dioxide
composition
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Computerized Instrumentation:
A computer interfaces with at least three instruments: a system that continuously samples
the subject’s expired air, a flow-measuring device that records air volume breathed and
oxygen and carbon dioxide analyzers that measure the composition of the expired gas
mixture
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A printed or graphic display of the data appears throughout
the measurement period
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Figure 1
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Doubly labeled water technique:
Working principle:
The doubly labeled water technique provides a useful way to estimate total daily energy
expenditure of children and adults in free-living conditions without the normal constraints
imposed by other indirect procedures
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Mechanism:
The subject consumes a quantity of water containing a known concentration of the stable
isotopes of hydrogen (2H or deuterium) and oxygen (18O or oxygen-18)—hence the term
doubly labeled water
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Labeled hydrogen
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leaves the body as water (2H2O) in sweat, urine, and pulmonary water vapor, while labeled
oxygen leaves as water (H2 18O) and carbon dioxide (C18O2) produced during
macronutrient oxidation in energy metabolism
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This procedure estimates
total carbon dioxide production during the measurement period
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85
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The
ingested isotopes require about 5 hours to distribute throughout the body water
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The progressive decrease
in the sample concentrations of the two isotopes permits computation of carbon dioxide
production rate
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Everest, cycling the Tour de France, rowing, and
endurance running and swimming
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6 Double labelled water technique
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Thus, then it remains un-applicable for sport, recreational and
occupational activities
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Indirect calorimetry
remains relatively simple to operate and less expensive to maintain and staff than direct
calorimetry

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