Every machine needs fuel for its effective functioning, just like that your brain is the engine of your body. There is no fixed percentage of how much energy is required by the brain. But on average, it is said that out of total body energy, 20% is used by the brain at resting state. The human brain only comprises around 2% of our entire body weight, but it consumes 20% of total energy. Glucose is solely the source of energy for the brain except for the period of starvation. The brain also requires energy to perform functions efficiently.
Our brain performs critical roles like learning, memorizing, signaling, and interpretation of impulses. Performing these functions requires a massive amount of energy, and it is very expensive when we talk in terms of energy use.
Having a rough idea of how much and where this energy is used, we can say that all parts of the brain do not equally use this energy. A quarter of energy is used by the brain cells to maintain themselves and to remain alive. After that, 75% is used for signaling that involves sending and processing signals in the brain.
Watch this video to know If we really use only 10 percent of our brain?
A considerable amount of energy is utilized at the point of synapses. This synapse is the gap between two neurons where all the electrical signaling takes place due to the transmission of the electric impulse. In these gaps, cells are pumping ions like potassium and sodium to create an electric charge so, a high amount of energy is required here.
There are two major types of tissues in the brain, Grey matter and white matter. Between these two, Grey matter requires more energy than the other. In white matter, a fatty layer of the myelin sheath surrounds axons. This sheath provides insulation, and thus, it prevents electric charge from leaking out. Due to this, the white matter requires 70% less energy.
Similarly, the energy requirement of all parts of the brain differs from another. The area of the brain involved in auditory processing (that is related to listening) requires far more energy than the olfactory system involved in vision and also more than memory storage. The reason is the fast and precise signaling necessary for hearing as we cannot afford any delayed response for a danger sound like a fire alarm.
A higher percentage of energy consumed by the brain is also because the brain never stops working. At night, even when you are sleeping, your brain roughly consumes the same amount of energy as it does during day time. If you are not engaged in verbal or gestural communication and sitting calm at a place, it does not mean that neurons in the brain are also not functioning. Constant communication is going on in our brain, and it requires bulk of energy.
Now the question is whether energy requirement by our brain is changed when we are involved in complex activities. During heavy exercise, walk, or running, our legs use about 3-4 times more energy. So, you might think that the answer is the same for the brain. But here in brain, the requirement of energy remains steady while performing complex activities too.
According to the myth, we only use 10% of our brain. The neurons of the remaining 90% are in silent mode or activated for a concise period, being energy efficient. What if we start to use 100% of it? Perhaps all of the energy will be used by the brain, and other organs may deprive of it.
Another interesting thing to know is that your brain has no reserve to store energy. It continually requires oxygen and energy in the form of glucose. All you have to do is to take small and frequent meals to be more efficient and active.
Until Next Time,
Team Doctor ASKY!