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The Light of Day Improves Mental Health

  • by
excerpted Gary Wenk Ph.D., Psychology Today and Journal of Affective Disorders

A recent study shows how more sunshine each day is good for your health.

Journal of Affective Disorders
Volume 295, 1 December 2021

Light has powerful effects on mood, sleep, and the circadian system. Humans evolved in an environment with a clear distinction between day and night, but our modern environments have blurred this distinction.

In general, greater daytime light exposure predicts better sleep quality, fewer insomnia symptoms, better mood and less fatigue.


  • Most of our waking hours are spent inside with artificial lighting conditions and reduced sunlight exposure.
  • This lifestyle disconnects us from our circadian rhythms and leads to a decline in mood and poor sleep quality.
  • A study of over 500,000 people showed that each additional hour spent outdoors significantly lowered odds of becoming depressed.
  • Greater sunshine exposure each day also reduced antidepressant usage, greater happiness and lower neuroticism.