The notes below are very simple notes identifying very approximate working and energy levels for typical UK humans.     The units used are ISO units of mechanical work. A kiloJoule is 1000 Joules and a joule defined as the energy expended (or work done) in applying a force of one newton through a distance of one metre (1 newton metre or N·m).    The dietary/nutritional energy values are normally identified using kilogram calorie (kcal ) .       ( 1 bar of dark Kit Kat has a nutritional value of 243kcal = 1013 kJ ).    The conversion factor is

1 kcal = 4,187 kJ.

the current UK normal calorie intake for a man to maintain his weight is about 2 500kcal per day = 12 217 kJ per day

BS EN ISO 8996:2004 : Ergonomics of the thermal environment. Determination of metabolic rate

The normal uses energy at a standard rate when lying down with an empty stomach.   The rate is called the basal metabolism and for a 70 kg man this is about 7000kJ per 24 hours.

A person also consumes energy (leisure joules) for everyday activities not associated with work rate required to do normal tasks.    The average leisure joules for a man is about 2400kJ per day.

( A man not engaged any physical activity other than light leisure activities would use about 9400kJ )

Energy is consumed for occupational activities which differ relative to the type of occupation.    The following table lists the daily energy levels related to humans involved in different employments.

Specific activities consume energy at different rates as shown below;

The human energy efficiency in completing task is illustrated below: