Getting less sleep than a person should can result in a weakened immune system, increasing the chances that one can get sick. Some experts point out that if a person gets only five hours of sleep per night over a period of five days, his or her immune system is weakened by 50%. One study showed that participants who slept fewer than seven hours a night and were then exposed to a cold virus were three times as likely to come down with a cold as study participants who got at least eight hours of sleep per night.
More about sleep and illnesses:
- Doctors recommend that the average adult get seven to eight hours of sleep every night. Children and teenagers should get at least nine hours.
- During sleep, people produce substances called cytokines that are crucial in fighting off infection. Less sleep means fewer cytokines, increasing a person's susceptibility to illness.
- Adults who oversleep are generally at a greater risk of developing health problems such as obesity, depression and heart trouble. Oversleeping in adults is defined as more than nine or 10 hours per night.