Work of breathing When there is increased gas flow resistance, the optimal respiratory rate decreases. This work (generally during the inhalation phase) is stored as potential energy which is recovered during exhalation. A pressure difference is required to overcome the frictional resistance to gas flow due to viscosity, and to provide non-elastic components of movement of the airway tissues to accommodate pulmonary volume change. Total work done against non elastic forces is 35% of total. Work is defined as a force applied over a distance. The SI unit of work is the Joule, equivalent to a force of 1 Newton exerted along a
Energy slave "Man and Energy", but the term did not come to be widely used until the 1960s, and is generally credited to Fuller. An energy slave is used to compare the productivity of a person and the energy that would be required to produce that work in the modern, oil fuelled industrial economy, although it could be applied anywhere that labor is produced with non-human sourced energy. It does not include the ancillary costs of damage to the environment or social structures. Formally, one energy slave produces one unit of human labor through the non-human tools and energy supplied by the