Disrupting Natural Sleep-Wake Rhythms Causes Behavior Changes

by: Dave Gabriele

(NaturalNews) Could allowing our lifestyles to disrupt the natural 24 hour rhythm of our bodies affect our behaviour? Researchers from The Rockefeller University and the Mount Sinai School of Medicine in New York have found that disruption of natural circadian rhythms, as seen in shift work or international travel, could be causing significant changes in our brains, bodies and behaviours.

A study published January 25, 2011, in the journal of the Proceedings of the National Academy of Sciences (PNAS), titled "Disruption of circadian clocks has ramifications for metabolism, brain, and behaviour", examined the effects of making subtle changes to the sleep-wake cycles of mice. The mice were placed in a 20 hour light-dark cycle, rather than the normal 24 hour cycle, for 10 weeks. Significant effects were found in the brains and behaviour of the mice.

The mice exhibited changes in metabolic hormones resulting in accelerated weight gain and obesity, as well as behavioral changes such as increased impulsiveness and decreased mental flexibility. "In the brain, circadian-disrupted mice exhibit a loss of dendritic length and decreased complexity of neurons in the prelimbic prefrontal cortex, a brain region important in executive function and emotional control. Disrupted animals show decreases in cognitive flexibility and changes in emotionality consistent with the changes seen in neural architecture."

The Rockefeller and the Mount Sinai research team, led by neuroendocrinology post-doctorate Ilia Karatsoreos, is attempting to map out how environmental disruptions of natural sleep-wake cycles affect human biochemistry in terms of hormones, metabolism and the genes that drive our circadian rhythm. The work suggests that our modern lifestyle could be significantly affecting us in ways not yet understood.

According to Karatsoreos, "The circadian system is a 'web,' with rhythms at the molecular level driving rhythms at the cellular level, which results in rhythms at the tissue level. This can lead to a cascading set of effects throughout the whole organism, and we want to understand how exactly that happens."

New York's Rockefeller University, established in 1901, is a centre for research and graduate education in the biomedical sciences, chemistry, bioinformatics and physics. PNAS is one of the world's most-cited multidisciplinary scientific serials. Since its establishment in 1914, it publishes leading research reports, commentaries, reviews, perspectives and colloquium papers.

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