The thymus is a small organ located in the upper chest. It produces T-cells, white blood cells known as T lymphocytes, that help to fight off infections. These cells attack viruses and bacteria. It is an area that helps to regulate the energy flow through the body and increases the mind-body connection. When we are stressed or ill, the thymus shrinks as a response. It’s an vital part of the immune system. If we are stressed and it shrinks, it increases our risk of infections and illness. Stress management is important to keep the thymus functioning properly.