Brain energy requirement, metabolism and neurotransmitter turnover consume % of the available oxygen and glucose in the body

Brain energy requirement, metabolism and neurotransmitter turnover consume 20 % of the available oxygen and glucose in the body.

  Even though, the brain is only about 2% of the body weight, it consumes about 20% of the body's energy. It is the main consumer of glucose-derived energy. When the mental strain increases, the brain's demand for energy in the form of oxygen and glucose is higher.