Get 10 minutes of outdoor light after waking
People who get more bright light in the morning tend to fall asleep faster at night.
The kettle clicks off, the ceiling light is on, and your phone is already glowing in your hand. To your body clock, that kitchen is closer to dusk than to day, so part of you still thinks it is night. A few minutes outside soon after waking gives your clock the bright signal it uses to set the day, and it asks for little more than drinking your coffee on the doorstep.
What it helps with
Trouble falling asleep
People who get more bright light in the morning tend to fall asleep faster at night.
Hard to wake up
More time outdoors in daylight is linked to fewer sleep problems and finding it easier to get up in the morning.
Low mood
People who spend more time outdoors in daylight have lower odds of depression and feel low less often.
Key facts
- 1After a summer week of camping with only natural light, eight adults' evening melatonin rise started about two hours earlier.
- 2In one study, a single winter weekend of camping moved people's body clocks earlier by roughly an hour and a half.
- 3In over 400,000 UK adults, more time spent outdoors in daylight was linked to fewer insomnia symptoms and easier waking.
- 4In the same UK data, more daytime outdoor light was linked to lower odds of depression.
- 5Office workers who got more bright light in the morning tended to fall asleep faster and report fewer depressive symptoms.
Why your clock needs morning light
Your body runs on an internal clock of roughly 24 hours that shapes when you feel alert and when you feel sleepy. Left to itself, that clock tends to drift a little later each day, and light is the main thing that keeps it on time. Light in the morning nudges the clock earlier, while bright light late in the evening pushes it later. Mornings spent indoors and evenings spent in front of screens can let it slide, so sleep comes later and waking feels harder. The simple rule is daylight first, screens later.
Why outside beats the kitchen light
Indoor light is much dimmer than it looks to you, because your eyes adjust so well. Brightness is measured in lux, and the gap between a room and the open sky is large, even on a grey day. Special cells in your eyes respond mostly to bright light and pass that signal to the clock in your brain. A window helps a little, but glass and distance cut the light a lot.
| Where you are | Typical brightness |
|---|---|
| Lit living room | About 100 to 500 lux |
| Overcast morning outside | About 1,000 to 10,000 lux |
| Sunny morning outside | 10,000 lux or more |
You don't need sunshine, and you should never look straight at the sun. Simply being outdoors with the open sky in view is what counts.
What the camping studies showed
In a well-known study led by Kenneth Wright, eight adults spent a summer week camping with only natural light. Their melatonin, a hormone that rises in the evening before sleep, started about two hours earlier, and their clocks lined up with sunrise and sunset. A later study by the same team found that one winter weekend of camping moved the clock earlier by roughly an hour and a half. In a UK Biobank study of more than 400,000 adults, people who spent more time outdoors in daylight tended to report fewer insomnia symptoms, easier waking and lower odds of depression. In a study of about a hundred office workers, those who got more bright light in the morning fell asleep faster and reported fewer depressive symptoms.
There are clear limits to this. The camping studies gave people whole days of daylight, far more than this habit, and the large studies find links rather than proof of cause. Nobody has pinned down an exact minimum, though more outdoor time tended to go with better sleep and mood, so a longer stay on dull days makes sense. Expect a gradual, modest change over a couple of weeks rather than a transformed night.
Fitting it into your morning
The easiest way in is to move something you already do outdoors. Drink your coffee on the step, take the dog out first thing, or walk the last stretch to the bus. Aim for within an hour of waking: if you get up at 6:30 a.m., be outside by 7:30 a.m. Keep your shoes and a jacket by the door, so "I couldn't find my other shoe" stops being a reason. Rain and grey skies still count, since a cloudy morning outside is usually brighter than any room in your home.
On a rushed or rotten day, two minutes on the balcony is still better than nothing. Leaving your phone inside helps your morning follow daylight first, screens later, and before long you become someone who greets the day outdoors. If trouble sleeping or low mood has lasted more than a few weeks, talk to a doctor, and keep this habit alongside their advice. Which part of your morning could you move outside tomorrow?
Action steps
- 1Step outside within an hour of waking. Spend 10 minutes outdoors on a doorstep, balcony, garden or the walk to work, before you settle in front of a screen. If you wake at 7 a.m., aim to be out by 8 a.m.
- 2Let your eyes take in the sky. Look around at the open sky and the street, skipping sunglasses if the light feels comfortable, but never stare at the sun.
- 3Stay a little longer on grey days. On cloudy or rainy mornings, spend 10 minutes or a bit more outside, under a porch or umbrella if you need one, at about your usual time.
Suggested routines
- Irregular sleep schedule
Wake up at the same time every day
Going to bed and waking at regular times is linked to a lower risk of early death, more strongly than total hours slept.
- Poor sleep quality
Stop drinking coffee 9 hours before bed
Studies show mistimed caffeine use reduces total sleep by about 45 minutes and deep sleep by 11.4 minutes.
- Irregular bedtimes
Go to bed at the same time every day
Keeping sleep to regular times is linked to a lower risk of early death, more strongly than total hours slept.
References
- Wright, K. P., et al. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology, 23(16), 1554-1558. doi.org/10.1016/j.cub.2013.06.039
- Stothard, E. R., et al. (2017). Circadian entrainment to the natural light-dark cycle across seasons and the weekend. Current Biology, 27(4), 508-513. doi.org/10.1016/j.cub.2016.12.041
- Burns, A. C., et al. (2021). Time spent in outdoor light is associated with mood, sleep, and circadian rhythm-related outcomes: A cross-sectional and longitudinal study in over 400,000 UK Biobank participants. Journal of Affective Disorders, 295, 347-352. doi.org/10.1016/j.jad.2021.08.056
- Figueiro, M. G., et al. (2017). The impact of daytime light exposures on sleep and mood in office workers. Sleep Health, 3(3), 204-215. doi.org/10.1016/j.sleh.2017.03.005