With normal breathing, about how many breaths does the average person take per day?

Your lungs work all day and night, whether you’re awake or asleep. That’s about 20,000 or so breaths per day with normal breathing. By the time you’re 50, you have taken around 400 million breaths. Lungs are organs which get oxygen into your blood and into every cell in your body. And they help get rid of carbon dioxide (CO2), which is toxic if you have too much.

Humans descended from the superfamily Hominoidea (10–20 million years ago); the earliest fossil records for hominids (earliest direct ancestors) date back 4–5 million years, and modern homo sapiens date back approximately 200,000 years. Over 2.3 billion years ago, early cyanobacteria began emitting O2 via photosynthesis. Considering that the earth’s atmosphere stabilized at ~21% O2 and ~78% nitrogen (N2) about 550 million years ago, it is safe to say that modern humans evolved to efficiently use this atmosphere for “normal” breathing.

Normal breathing is defined as the movement of air in and out of the lungs in an environment with infinite volume and stable external pressure. Normal breathing is an autonomous function performed without conscious effort, although humans can take conscious control for actions such as breath-holding, talking, singing, swimming, and exercise.