Light activates and regulates your biorhythm

Some suffer from "winter blues", a seasonal melancholy that occurs in fall and winter when the length of each day becomes shorter and the sunshine is less bright.

Many of you have likely experienced some sort of depression for no specific reason on a gloomy day.
On a bright sunny day, you likely have felt positive and joyous.

The reason is that  bright morning sunshine positively effects your autonomous nervous system, activates the sympathetic part of your nervous system, brings up your body temperature, and thus awakens your body in a normal way.

The morning light also suppresses the secretion of melatonin (a hormone derived from serotonin especially in response to darkness). This process results in more natural awakening which enables people more rested and refreshed.

Rhythms in our body that repeat at approximately every 24 hours are called circadian rhythms. The most prominent of these rhythms is the sleep/wake cycle. Circadian rhythms are synchronized to the solar day by light/dark cycles.

Since we spend most of our time indoors at the office or home,  we lack the benefits of sunshine. 
Also, unusual hours and work schedules force many of us to stay awake and active at night, which effects our biological clock, and may result in health problems.

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