The old adage about “early to bed, early to rise” has more truth to it than we ever realized. We are finally coming to recognize how insufficient sleep affects our immune system. There have been several studies over the last twenty years that clearly demonstrate this relationship.
We know that insufficient sleep decreases our production of CD3+ CD4+ CD8+ T cells. These are cells that are very much involved in fighting off infection. Our bodies also produce increased amounts of proteins called cytokines during sleep. These are necessary for fighting infection and regulating sleep itself. When we are sleep-deprived, the production of some of these cytokines becomes abnormal and can promote inflammation and hinder our ability to fight infections.
In one recent study titled A Prospective Study of Sleep Duration and Pneumonia Risk in Women published in the journal Sleep, a report of inadequate sleep resulted in a 40% increased risk of pneumonia. In an earlier study involving 276 healthy subjects, inadequate sleep resulted in a much greater chance of developing a respiratory infection.
Several other studies have demonstrated that insufficient sleep can result in a minimal antibody response to vaccinations. In one, sleeping less than six hours a night produced a poor response to hepatitis B vaccination. In others, poor sleep has also been correlated with a substandard response.
Because of these and other findings, we now know that sleep directly affects our ability to cope with and prevent infection. Most studies have demonstrated that we need at least six or more hours of sleep to avoid these changes in our immune system. When we get less than this amount, we start to see alterations in our immune system and a decreased ability physiologically to deal with stress.
What can we do to avoid this? We can make sleep a priority in our lives. It is estimated that nearly one-third of the population gets less than six hours of sleep each night. This many people more susceptible to infection, resulting in illness and days off work, becomes a huge problem. We can improve our sleep hygiene by turning off computers and smart phones at least one hour before going to bed. We can keep our rooms at a comfortable and cool temperature conducive to sleep. Finally, we can keep a stable sleep/wake schedule, even on weekends, trying to guarantee at least seven hours of sleep. If we do all of these things, our immune system will be much more likely to function normally and keep us healthy.