The human brain is a very powerful organ. Even though it makes up only about 2% of our body weight, it uses almost 20% of the body’s total energy.
This happens because the brain is always active.
Even when we are resting or doing nothing, the brain is still working. It controls breathing, heart rate, body temperature, and also keeps processing thoughts, emotions, and memories.
The brain mainly uses glucose as its source of energy. This energy is required for nerve cells to send signals and communicate with each other.
Activities like thinking, focusing, learning, and decision-making all increase energy use in the brain. This is why sometimes we feel mentally tired, even without doing any physical work.
From a medical point of view, the brain needs a continuous supply of glucose and oxygen. If this supply is disturbed, it can lead to problems like:
- dizziness
- confusion
- weakness
- loss of consciousness (in severe cases)
Conditions like hypoglycemia can directly affect brain function because the brain depends heavily on glucose.
This shows how important proper nutrition and stable blood sugar levels are for normal brain activity.
But this also makes us think if the brain never truly “rests”, what actually helps it recover from mental fatigue? 
MBH/PS