13. Immune System
The feeling of always being tired can be very exhausting. There are a number of illnesses that may give you this feeling. However, the decreased function of your immunity system can be dangerous. Your immune system is in charge of fighting diseases. It includes bacteria, viruses and other foreign bodies that enter the body.
Your immune system could be compromised, causing you to get sick more frequently. Your immune system will wear down over time and become less able to perform as it should. This allows for more germs to enter.
It can cause many infections that are dangerous. It is vital to seek a diagnosis as soon as you feel tired all the time. It is vital to get the right treatment in order to prevent further health complications.