Final answer:
The normal value of work of breathing varies depending on respiratory rate and tidal volume. It refers to the energy required to move air in and out of the lungs during breathing.
Step-by-step explanation:
The normal value of work of breathing can vary depending on several factors, including respiratory rate and tidal volume. The work of breathing refers to the energy required to move air in and out of the lungs during breathing. It can be measured in liter-atmospheres (L-atm) or joules (J). Under non-exertion conditions, the human respiratory rate is 12-15 breaths per minute, and the average tidal volume is approximately 500 mL. A normal breath involves inhaling and exhaling this amount of air, resulting in a certain amount of work being done. However, the specific numerical value of the normal work of breathing in liter-atmospheres or joules would depend on the specific respiratory rate and tidal volume of an individual.