How much oxygen does the brain need to stay conscious?

As an expert in the field of neuroscience, I can provide you with information on the oxygen requirements of the human brain. The brain, despite being only about three pounds or 1.5 kg in weight, is a highly metabolically active organ. It consumes a significant portion of the body's total oxygen supply to maintain its complex functions, including consciousness. The brain's oxygen needs are closely tied to the body's overall oxygen consumption. In general, an adult's brain requires approximately 20% of the body's oxygen. This percentage is crucial because oxygen is essential for the production of adenosine triphosphate (ATP), the primary energy source for cellular processes. Without sufficient oxygen, the brain cannot produce enough ATP, which can lead to a loss of consciousness. It's important to note that the brain's demand for oxygen can vary based on factors such as physical activity, cognitive workload, and health conditions. Additionally, the brain has a limited capacity to store oxygen, so a continuous supply is necessary to prevent cognitive impairment or loss of consciousness.

The human brain weighs on average three pounds, or 1.5 kg. The human brain is about the size of a cantaloupe. How much oxygen does the brain need to stay "conscious"? An adults brain requires around 20% of the body's oxygen.