Sleep · Protocol 3 of 15
Dim the lights as night falls
1In 30 seconds
After sunset, keep your lights low, warm and below eye level, and avoid bright overhead lights in the hours before bed. Bright light at night tells your brain it is still daytime, which blocks melatonin and can drag down your mood the next day.
2Picture it
3Why do it
- 1
Your melatonin can rise on time, so you get sleepy at your normal bedtime instead of feeling wired.
- 2
You are likely to sleep more deeply and wake with better mood, focus and energy.
- 3
Your home feels cosier in the evening, and you save a little on electricity too.
4How to do it
- Work out your temperature minimum. Average your wake-up time over 3 to 4 days and subtract 2 hours. If you wake at 6:30 a.m., it is about 4:30 a.m.
- Avoid bright artificial light for the roughly 6 hours before that time. In this example, that means from 10:30 p.m. until 4:30 a.m.
- Start dimming the lights from around 8 or 9 p.m. Use lamps placed low in the room rather than overhead lights.
- Swap to warm amber or red bulbs in the rooms you use at night, or use candlelight and blow it out before you sleep.
- If you must use screens at night, wear glasses that filter out blue and green light, but never wear them to drive.
- For night-time bathroom trips, use a dim red or amber night-light instead of the main switch.
5Make it work in India
- Switch off the white tube light or bright overhead LED panel after dinner and use a table lamp with a warm yellow bulb instead. These are cheap and easy to find.
- A diya or candle in the evening is a lovely, very low-light option. Keep it away from curtains and never leave it burning when you sleep.
- In a joint family where others watch TV late, sit further from the screen, keep a side lamp on rather than the tube light, or wear blue-and-green blocking glasses.
6The long read: the science2 min read · tap to open
Most homes today are lit by LEDs. They are cheap and efficient, but they give off a lot of short-wavelength, bluish light. That is exactly the kind of light your melatonin-sensing eye cells react to most strongly. At night, these cells become far more sensitive than in the day. So a light that seems ordinary to you looks like daybreak to your body clock.
Here is how much light different sources give, measured in lux. A candle gives about 1 lux, and a full moon gives less than 1. A table lamp gives around 200 to 400 lux. Overhead LED lighting gives 500 to 1,000 lux. That gap is enormous, and it explains why dimming and lowering your lights helps so much.
There is also a mood link. A small brain area called the habenula helps create feelings of disappointment, which in normal life teaches us to avoid bad choices. Animal studies, and early work in people, suggest that bright light at the wrong time of night activates a nearby region. That raises cortisol, lowers dopamine and can bring next-day anxiety and poorer learning, even if you sleep the same number of hours.
Your brain does not read the clock on the wall. It reads its own internal time, which you can estimate from your temperature minimum, about 2 hours before you usually wake. Keep things dim in the 6 hours before that point and your clock stays on track. Remember that any light that is bright enough will shift your clock, whatever bulb it comes from.
Good evidence Many lab studies show bright evening light, especially from LEDs, lowers melatonin and delays sleep; the links to low mood come mostly from animal work and early human data.
Questions people ask
Will one late concert or wedding ruin my sleep?
No. Your sleep timing reflects your habits over several days. Aim to get it right about 90 percent of the time and enjoy the occasional bright, late night.
I feed my baby at night. Does this matter?
Yes, it helps both of you. Keep the lights as dim as you can, or use a red or amber bulb, so you fall back asleep more easily and your baby’s body clock learns day from night.
7Be careful
Never drive in blue- or green-blocking glasses, because you may miss road signs and signals. Older adults and anyone unsteady on their feet should keep enough low light to move about safely and avoid falls. Never leave candles or diyas burning unattended.
8Try it for 7 days
Tap a day each time you dimmed lights after dark.
From the book: “Avoid Viewing Bright Lights in the Final Hour Before Bedtime” (Sleep Protocol 3). Evidence rating and India notes are our own.