Most of us are aware of what happens to our body when we exercise: we get more muscle, we have more resistance ... We feel that daily activities such as climbing stairs become easier if we exercise on a regular basis.
When you start exercising your brain recognizes that moment as one of stress. As the blood pressure increases, the brain thinks that you are fighting an enemy or running away from it. To protect you and your brain from stress, you release a protein called BDNF (Brain-Derived Neurotrophic Factor). This BDNF has a protective and repairing element that affects your neurons and also acts as a reset switch. That is why we often see things more clearly and feel more liberated right after exercising. Also for what we are happier.
At the same time, endorphins, another chemical in our body to fight against stress, are released into your brain.