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Ask the Experts


What exactly is Light Deprivation? I live in Illinois and around this time every year I feel "blue", not depressed per say, just kind of "blue".

I find that if I visit a tanning salon, maybe once a week, it does seem to help. But I would like a clear definition, and is tanning really helping?

Answered by: Michael Terman

Adequate daily exposure to full daylight levels -- whether outdoors or from indoor artificial lighting -- is very important to maintain stable, refreshing sleep and normal mood and energy.

There are two major factors that confound such exposure:

(a) short days with late sunrise in winter; and

(b) inadequate or poorly timed interior lighting in contemporary living/working environments.

The major corrective is supplementary light exposure -- "light therapy" -- upon awakening in the morning, as described in detail on

As for tanning salons: just don't do it even if it lifts your mood! The skin cancer hazard from ultraviolet radiation is real, and the safe alternative using UV-filtered light to the eyes (not the skin) has proved effective in clinical trials of thousands of patients.