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Less Sleep Associated with Shorter Telomeres

By Ross Pomeroy

British researchers have associated sleep duration with telomere length in males. For guys, it's yet another reason to focus on catching more of those Zs.

Telomeres are short regions of repetitive nucleotides at the end of our chromosomes. Their primary purpose is to protect the chromosome, and thus the vital information that it contains, from deterioration. Scientists have linked the shortening of telomeres with aging, but they're not certain as to whether telomere shortening directly contributes to aging. Still, many hope that by keeping telomeres long, we can extend the human lifespan by as long as 30 years!

In the present study, researchers from University College London and Cardiff Metropolitan University recruited healthy subjects -- 228 women and 206 men -- from the Whitehall II Cohort study, a long-term health investigation that has been following 10,308 working men and women since 1985. Subjects were surveyed about the average amount of sleep they receive each night, with categories of "5 hours or less," "6 hours or less," "7 hours or less," and "more than 7 hours." The researchers then measured the average telomere length of the participants' white blood cells.

In men, the researchers found a significant linear association between sleep duration and telomere length. Subjects reporting greater average amounts of sleep had longer telomeres. This was independent of other factors such as age, educational attainment, employment status, BMI, smoking, hostility and symptoms of depression.

"Telomeres were on average 6% shorter in men sleeping 5 hours or fewer compared with those sleeping more than 7 hours per night," the researchers say.

Two primary limitations of the study were its cross-sectional nature (meaning that we don't know whether reduced sleep led to shortened telomeres or vice versa) and that sleep data was self-reported.

The study sets the stage for future longitudinal studies on whether shorter sleep leads to accelerated telomere shortening and advanced cellular aging.

Source: Jackowska M, Hamer M, Carvalho LA, Erusalimsky JD, Butcher L, et al. (2012) Short Sleep Duration Is Associated with Shorter Telomere Length in Healthy Men: Findings from the Whitehall II Cohort Study. PLoS ONE 7(10): e47292. doi:10.1371/journal.pone.0047292

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