At rest, what percent of the body's energy expenditure is used for breathing?
a. 3%
b. 5%
c. 8%
d. 10%
Answer: a. 3%
At rest, about 3% of the body's energy expenditure is used for breathing. During moderate intensity exercise, this increases to between 3 and 5%. In very high intensity activity, the expenditure can increase to 10% or even 15% in trained athletes.