I just came across an article published last month in the Proceedings of the National Academy of Sciences, US. It turns out that shifting of the circadian clock – the natural light/dark and sleep cycle represented in mammalian hypothalamic suprachiasmatic nuclei – is probably not good for you. If lack of sleep in the modern era isn’t bad enough, the daily deviation from the natural synchronous rhythms of activity and light, brought about mainly with the advent of electric lighting, affects us as well (rather than just the absolute amount of sleep).
Researchers at Rockefeller University in New York bounced mice off the normal 24hr light cycle they (and, of course, we) evolved in response to, and found devastating effects:
Housing in these conditions results in accelerated weight gain and obesity, as well as changes in metabolic hormones. 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.
Maybe this means we should start going to work at 5:30 in the morning, get home at 2:00pm, and turn off the lights at 6:00.
Oh yea, and no more transoceanic flights, night shifts, or midnight screenings….and last call is now at 8:00pm.