The amount of sleep you get is associated with a whole assortment of other characteristics such as life satisfaction, BMI and even telomere length. Telomeres are DNA segments at the end of our chromosomes — some have compared them to the ends of a shoe lace. As our telomeres shorten, it hampers the ability of our cells to replicate and repair themselves. The book, Telomere Effect — by the Nobel Prize winner who discovered telomerase and the role telomeres have in the aging process — looks at habits and lifestyle that impact telomere length.
The average American gets just under seven hours of sleep, and in general when we don’t get enough — less than seven hours — it’s not just our health that suffers. Lack of sleep is associated with higher blood pressure, as well as increased risks for diabetes and depression.
Sleep is actually broken into a number of stages or cycles, many of us have heard about REM sleep the sleep cycle characterized by rapid eye movement when our most vivid dreams occur.
Less well known is the Deep Sleep stage just before REM sleep, also sometimes referred to as “slow-wave sleep” or “Delta Sleep.” This stage is considered the deepest part of the sleep cycle and is characterized by a pattern of brain activity called delta waves. The strength of delta waves reflects how deeply a person sleeps — oddly scientists use the term “sleep intensity” when talking about deep sleep. Several studies have found that a genetic variant on the ADA gene, which produces the enzyme adenosine, influences how deeply people sleep.
Throughout the sleep stages many of us move involuntary. Known as periodic limb movement, on average a person might have 10 of these an hour. 23andMe’s Sleep Movement report looks at how your genetics may influence whether you move more or less than average during sleep. The report is based on several studies that point to variants in the BTBD9 gene on chromosome 6, which creates the protein BTB. While not much is known about this protein, it appears to influence not just sleep and movement but also our sense of touch and how we metabolize iron.