No one wants to get sick. One of the greatest health benefits of a good night’s sleep has to do with the connection between sleep and immune system response. (There’s a reason why you’re feeling more tired than usual when you’re getting sick: Sleep increases immunity, so your body encourages more of it.)
Research has shown that being well-rested dramatically decreases the chance of picking up illnesses like the common cold! UCSF researchers observed and divided participants into groups based on their amount of sleep, then exposed them to the common cold virus. The surprising result was a clear linear relationship between hours of sleep and infection rate. The less sleep a person had in the week before exposure, the more likely they would be infected and catch a cold. In those with an average of five hours of sleep, the infection rate was almost 50 percent, while those with a pre-exposure average of seven hours or more had an infection rate of just 18 percent.
Sleep doesn’t just fight colds, though. It works to prevent all types of illness, infection and malignancy.
A UCLA researcher showed that even one night of sleep deprivation affects Natural Killer (NK) cells, which are special “soldiers” of the immune system most known for killing cells infected with viruses, as well as detecting and addressing early signs of cancer. This studied show that a single night of only four hours of sleep depleted 70 percent of the NK cells that would circulate with eight hours of sleep.
Another study of nearly 25,000 European subjects supported an association between six hours or fewer of sleep and an increased risk of developing cancer, relative to those with at least eight hours of sleep.

20May