Have you noticed that it can be harder to get to sleep in the lighter nights of the UK summer? This is due to circadian rhythm and the impact light has upon it and our sleep. I think we inherently know that light interferes with our sleep and we sleep better when it is dark, however modern living can have us permanently ‘lit up’, as we have artificial light available to us 24/7.
Although we are looking at our bedroom environment, it is worth noting that we need sunlight, which is the most intense light available to us, to help set our circadian rhythm and exposure to daylight and the sun can have a very beneficial impact upon our ability to sleep well.
When it comes to artificial light and the lights we use in the bedroom, there are differences in illumination, brightness and wavelength.
Blue light, has a shorter wavelength than orange light, and is emitted from LEDs, fluorescence light and our electronic devices (as mentioned in a previous lesson). This shorter wavelength blue light can interfere with melatonin production (1).
Suggest to your client to have dim lights in the bedroom, using a small lamp rather than bright overhead LED lights which are often found in the room. You can put in a lower wattage or lower lumen bulb, a warmer coloured bulb can be beneficial as it has a longer wavelength and can help to feel relaxed and more conducive to sleep.
As previously mentioned in the lesson on Electronic Devices, it is useful to remove them from the bedroom.
Sleeping in the Dark
It is best to sleep in a dark room, pitch dark removes distractions and possible disruptions to sleep, as closing our eyelids isn’t enough to block out any light which may be in the bedroom (2).
Other research has indicated we need to sleep in the dark as any low level light which seeps through our eyelids whilst asleep can cause:
- Eye strain resulting in sore, tired eyes, discomfort and trouble focusing (3).
- Weight gain as sleeping with the lights on appears to affect the circadian rhythm of metabolism and a study showed that a 10lb increase in weight was found in women sleeping with the lights or TV on (4).
- Cancer risk with one study showing high levels of artificial light and prostate/breast cancer, although further study is needed to indicate a true causation (5).
Whilst, I don’t think we need to be ‘scare-mongering’ clients with why you must sleep with the light off, these studies are a useful insight into why a dark room is important to our sleep.
As coaches, we can suggest to a client to alter their lighting, sleep with the lights off, have a black out blind/curtains or wear an eye mask and check in as to whether they feel they’ve gotten a better night’s sleep and feel more rested.
Reasons Why People Say They Sleep Better With the Lights On and What To Do
It could be due to comfort as they are afraid of the dark. Suggest they have a timer so they go to sleep with the light on but it switches off after they are asleep. If it is a deep fear they may need to see someone who specialises in phobias.
They get up in the night to go to the toilet and are worried about not seeing or tripping over something. Suggest they have motion sensor lights or dim night lights (these can be found in shops specialising in baby items or the baby section of larger stores) and ensure the path to the bathroom is clutter free.
Their partner won’t sleep without them on leaving them unable to sleep in the dark. Ask if there is any possibility of compromise with their partner using a dimmer light and if not can your client use an eye mask.
The attachment to falling asleep with the TV on. Try and establish a new bedtime routine which switches the TV off before getting cosy in bed. If that is an issue, can they have the TV on a dim setting and is there a timer setting with the TV which can be set so the TV won’t be playing all night (if not, use a timer plug).
References
- Lockley, S. W., Brainard, G. C., & Czeisler, C. A. (2003). High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. The Journal of clinical endocrinology and metabolism, 88(9), 4502–4505.
- Figueiro, M. G., & Rea, M. S. (2012). Preliminary evidence that light through the eyelids can suppress melatonin and phase shift dim light melatonin onset. BMC research notes, 5, 221.
- Suh, Y. W., Na, K. H., Ahn, S. E., & Oh, J. (2018). Effect of Ambient Light Exposure on Ocular Fatigue d