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Chilean Miners/Biological Clocks: Johns Hopkins Expert

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October 13, 2010

TO:  Reporters, editors, producers

FROM:  Lisa De Nike | 443-287-9960 | Lde@jhu.edu

RE:  News source on how prolonged lack of daylight affected the Chilean miners

Reporters working on stories about the impact of the Chilean miners’ long ordeal underground should consider speaking with Samer Hattar, an assistant professor of biology at The Johns Hopkins University.

An expert on how exposure to light – or lack thereof – affects mammals’ biological clocks and health, Hattar can discuss the likely impact that 69 days without natural light had on the miners’ physiology, especially their sleep-wake cycles.

“The thing to remember is that we need exposure to light in order for our internal clocks – the mechanism that sets our sleep-wake cycle and regulates our moods, metabolism and so on – to function properly,” Hattar says. “The miners didn’t have that. As a result, for all intents and purposes, their biological clocks just kept running, which undoubtedly threw off their sleep-wake cycles.”

The miners’ well-publicized efforts to adhere to strict sleep-wake schedules (one group slept while the others were awake, and vice versa) may have helped them organize their day, but would have had no discernible impact on their biological clocks, Hattar said.

Samer Hattar

Samer Hattar

“There is no evidence that sticking to a regular schedule of sleeping and waking the way these men did would have any positive effect on the mechanism that our bodies use to set our internal clocks,” he said.

Long-term interruption of those circadian rhythms has been linked to symptoms ranging from depression and mood disorders to insomnia, metabolic and hormonal disturbances, headaches, impaired concentration and even diabetes and cancer.

Fortunately for the miners, the cure is easy.

“The miners need to be sure to expose themselves to natural light at the correct time of day – daytime – to readjust their clocks and receive the necessary photons to enhance their moods,” Hattar advised. “We don’t know precisely how long it will take them to completely reset their clocks, but it could be any time from a few days to a week or more.”

Reporters wishing to speak with Dr. Hattar should contact Lisa De Nike at 443-287-9960 or by e-mail at Lde@jhu.edu.


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