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1.4. LIGHT AND HEALTH
Our daily functioning varies in line with the 24
hours of the day. This circadian (from circa =
about, dies = day) variation is caused by our
internal biological clock, which gets its timing
cues from the external light-dark cycle. A well-
synchronized biological clock helps regulate
our mood, sleep, energy, appetite and diges-
tion and helps ensure our well-being. Some-
times our internal clock gets out of sync with
the external world, – for example, because of
long-distance travel or working night shifts. This
can cause various health-related problems.
Many factors in day-to-day life diminish the
ability of our internal biological clock to syn-
chronise us properly with our external environ-
ment. We no longer work regularly from dawn
to dusk: many people work irregular hours or
must follow shift-work schedules, or travel ex-
tensively across several time zones. Also, mod-
ern electric lighting allows activities to extend
well into the night.
These factors can be balanced through ex-
posure to bright light that is timed with the in-
dividual’s needs in mind. For more information
about how to use the device to improve your
well-being, visit
www.valkee.com/support.
Keep dry
