Cold sore: Viruses or localised infections can cause the eye to redden â the problem usually starts in one eye, but can spread to both. The cold sore virus, which 90 per cent of us carry, can sometimes also infect the eye, causing inflammation.
Endorphins are chemicals, called peptides, that are made in the body. They have much of the same effect on a person as opium or morphine. As a result, they actually lower the feeling of pain in the body and can create a feeling of bliss or euphoria.
The neuron receptors endorphins bind to are the same ones that bind some pain medicines. However, unlike with morphine, the activation of these receptors by the body's endorphins does not lead to addiction or dependence. Regular exercise has been proven to: 1  Reduce stress. 2  Ward off anxiety and feelings of depression. 3  Boost self-esteem.