Sleep deprivation is associated with many chronic health conditions, including Alzheimer’s disease, cardiovascular disease, and type 2 diabetes. Roughly one-third of all adults living in the Unites States are sleep-deprived. A recent study demonstrates that sleep deprivation impairs the body’s immune response, providing a link between inadequate sleep and chronic disease.

How much sleep a person needs is largely dependent on their chronotype – an individual’s innate tendency to sleep at a particular time during a 24-hour period. Chronotypes are based on circadian rhythms and are genetically determined, making it difficult to identify proper controls for sleep studies.

To address this problem, this study involved 11 pairs of monozygotic (identical) twins whose self-reported sleep patterns differed by at least 60 minutes per night. The authors of the study monitored the participants' sleep and analyzed their gene expression profiles.

The average sleep duration for all the study participants was roughly seven hours and 20 minutes per night. The average sleep duration difference among the twin pairs was one hour and four minutes. Gene expression profiles differed between the twins, as well. In particular, poor sleep altered gene expression of factors involved in the immune response of white blood cells. These alterations could contribute to the dysregulated immunity often observed in sleep-deprived people.

• Link to full study.

• Watch this clip in which Dr. Matthew Walker describes some of the deleterious effects that poor sleep has on the immune system.