Morning sunlight

How sure we are

Kept separate from the priority score on purpose: confidence in the evidence never raises how worth-it something is.

What we read

• Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults

  PLOS Biology · 2022

  Expert consensus sets a minimum of 250 melanopic lux at the eye held throughout the day — a threshold, not a dose — and names daylight as the easiest way to meet it: outdoors clears it instantly, most indoor light never does.

• Entrainment of the human circadian clock to the natural light-dark cycle

  Current Biology · 2013

  A week of camping with only natural light shifted participants' internal clocks about two hours earlier and shrank the differences between individuals.

• Impact of windows and daylight exposure on overall health and sleep quality of office workers

  Journal of Clinical Sleep Medicine · 2014

  Office workers in windowless rooms slept worse and reported poorer wellbeing than comparable workers with daylight.

• View through a window may influence recovery from surgery

  Science · 1984

  Gallbladder-surgery patients whose window faced trees left hospital sooner and needed fewer strong painkillers than matched patients facing a brick wall.

• Morning sunlight reduces length of hospitalization in bipolar depression

  Journal of Affective Disorders · 2001

  Of 602 depressed inpatients, those with bipolar depression in east-facing rooms, which catch direct morning sun, went home on average 3.67 days sooner. No effect appeared in unipolar patients.

• Sunny hospital rooms expedite recovery from severe and refractory depressions

  Journal of Affective Disorders · 1996

  Patients treated for depression in sunny rooms were discharged about 2.6 days sooner than those in dull rooms.

• Dying in the dark: sunshine, gender and outcomes in myocardial infarction

  Journal of the Royal Society of Medicine · 1998

  Among 628 heart-attack patients, deaths were consistently higher in dull rooms than sunny ones (39 of 335 versus 21 of 293).

• Effects of light on human circadian rhythms, sleep and mood

  Somnologie · 2019

  A review concluding that daytime exposure to bright, short-wavelength-rich light is associated with greater evening sleepiness and better sleep quality.

Research from University of Colorado Boulder · Northwestern University · University of Oxford. We cite their published work. They have no involvement with Anew.

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