View Morning Sunlight

• Get outside within 30–60 minutes of waking up to expose your eyes to direct sunlight (自然光). ^{1 2 3}
  • This typically requires about 10-15 minutes of sunlight on a sunny day, while cloudy days may require 20 minutes or more. ⁴
  • Feel free to use the time outside to exercise (jump rope), walk, eat a light breakfast or journal in the sunlight.
  • If you wake before sunrise, turn on bright artificial lights until the sun rises. Once it rises, get outside if possible. ⁵
• Try to get morning sunlight before the “circadian dead zone,” which occurs between 11 a.m. and 3 p.m.
  • While sunlight exposure during this period has many benefits (e.g., mood, vitamin D and hormone levels), it won’t effectively shift your internal clock.
• Even on overcast days, natural sunlight is usually brighter than artificial lighting.
  • Don’t use screens or indoor lighting as your light source, as they have different spectrums and light profiles for photon energy.
  • If natural sunlight isn’t an option for any reason, consider using very bright artificial lights or a light therapy lamp (ideally 10,000 lux or brighter).
  • One can use a light meter app to detect photon energy in the environment.
• Increases early-day cortisol release

View Afternoon Sunlight

• While morning sunlight is critical for setting your circadian clock, afternoon sunlight serves as a secondary cue ,⁶ signaling the body to prepare for night.
• Encourages the correct level of melatonin

Limit Nighttime Light

• After sunset and in the hours before bedtime, opt for dim, low-positioned lights, such as table lamps, instead of overhead lights.
  • This low ambient light supports natural melatonin production and makes it easier to fall asleep.