ENERGY COST OF PHYSICAL ACTIVITIES
Next to Basal Metabolism it is the
physical activity, which accounts for the largest energy expenditure.
There is a wide variation from
individual to individual in occupational activity.
The energy required for the actual
physical activity varies depending on the type of occupation of an individual.
For computing energy requirements,
the occupations have been classified as sedentary, moderate and heavy.
ICMR classification of activities based on occupation is given in table-20C.
The energy cost of physical activities is expressed in terms
of BMR units.
BMR Unit :
The energy cost of rest and physical
activity is expressed as multiples of BMR which is called the physical activity
The physical activity ratio expresses the energy cost of an
individual activity per minute as ratio of the cost of BMR per minute. Hence it
is advantageous to express the energy expenditure in terms of BMR units.
THERMIC EFFECT OF FOOD
Food ingestion stimulates metabolism and requires energy to
meet the multiple activities of digestion, absorption and
transport of nutrients. This
overall stimulating effect of food
is called dietary thermogenesis or thermic effect
of food (formerly called as specific dynamic action (SDA). The
increase in energy cost because of thermogenesis is 10%.