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Does bright light really make you feel brighter - or is this just smoke and mirrors?


It's mental health day on Sunday. Apt perhaps because, whether you work or not, we tend to find it easiest to smile on the weekend - and head down in the dumps on Monday.

That may be because some of us work in places with little or no daylight - whether that's a spare bedroom or the desk furthest from the window. This paper explains how people in windowless environments reported poorer scores on role limitation due to physical problems and vitality—as well as poorer sleep quality overall. Compared to the group without windows, workers with windows tended to get more exercise and get more sleep.  


So how does that work? this paper gives a great overview of the mechanisms involved- not only the sleep-wake cycle, but other direct physiological effects. Scroll down to page three, section four - and check out some of the references. To paraphrase ... light can trigger physiological changes (heart and thermoregulation) within a minute of exposure and the limbic structures (amygdala and hippocampus) within seconds.... artificial light exposure at night time and/or particular spectral compositions of the light have direct effects on mood and behavioral state... light can affect mood, alertness/attention, waking EEG, and cognitive performance in people. ..'

It's tempting to think that a bright light - perhaps even one of the SAD lamps that Amazon is pushing right - is enough. But this thesis from Finland suggests that combining a hit of light with 20 minutes of aerobic exercise will give you more bang for your buck.