The latest scientific study shows that sleeping less than five hours can endanger the health of the body by 15 percent.

When a person is awake, the brain, like the rest of the body, uses chemical substances known as neurotransmitters for mutual "communication", that is, sending information from the nervous to the immune and other systems.

Sleep helps keep neurotransmitter stores at optimal levels.

When a person does not get enough sleep or has bad sleep, the body produces less neurotransmitters.

As a consequence, many body functions, including the immune system, do not function optimally.

Namely, while a person sleeps, the body produces more white blood cells and cytokines/products of the cells of the immune system/, which act as messengers of the immune system and help fight infections and diseases.

By itself, bad sleep can cause their reduced production, which affects the decline of immunity.

Lack of sleep makes a person more susceptible to even a common cold, researchers warn.