Wednesday, 22 May 2013

Lights Out Goes Mainstream

Mainstream are playing catch up!  Peering at bright screens after dark could harm health, doctor claims. None of this is news to those of us who have looked at our health and fitness from an evolutionary perspective for any lingth of time.

UPDATE: Nature has more detailed coverage of Charles Czeisler's work - including a couple of pithy observations:
  • Paradoxically, the daily peak of waking energy driven by the brain's master circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus occurs not at the start but near the end of our usual waking day, providing us with a 'second wind' that keeps us going as the day wears on. Before the widespread use of electric light, people probably experienced that second wind in the mid-afternoon, keeping them going until night fell. But light exposure after sunset signals 'daytime' to the SCN, shifting the clock later, postponing the second wind and delaying the onset of melatonin secretion. As a result, many people are still checking e-mail, doing homework or watching TV at midnight, with hardly a clue that it is the middle of the solar night. Technology has effectively decoupled us from the natural 24-hour day to which our bodies evolved, driving us to go to bed later. And we use caffeine in the morning to rise as early as we ever did, putting the squeeze on sleep.
This brings to mind Wiley and Formby's observation that our bodies are stuck in a perpetual summer, preparing for a winter that never comes.

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