Light and Sleep

There was an interesting article in The Guardian today about a new blood test that can detect whether someone is sleep deprived. The idea is to use it to prosecute drivers involved in accidents who have had less than 5 hours sleep. According to the article driving after less than 5 hours sleep is as dangerous as driving after drinking alcohol. Experts are divided on the ethics of this.

This was particularly interesting for me for two reasons. Firstly, because this time last week I was on a flight from Manchester to LHR, en route to Texas where I took part in a couple of panel discussions about colour psychology having gone to sleep at 11:30pm the night before and left the house at 3:30am after fitful sleep for less than four hours. During the 1.5 hour drive from Leeds to Manchester in the early hours I had felt completely awake; however, I wonder whether I would be able to make this journey in a few years if the legislation is introduced.

But secondly, because my own research is concerned with the effect of light sleep and the devastating effects that lack of sleep can have on our health and wellbeing. A discussion about this topic actually came up during the Texas trip. I would encourage everyone to listen to Matt Walker’s superb TED talkSleep is your super power. We now know that light plays a crucial role in maintaining a healthy sleep schedule. Healthy sleep is entrained by exposure to bright light in the few hours after waking and to lack of exposure to light in the hours before going to bed. There is debate about the relatively importance of the light being blue. The light-sensitive cells in the retina that are implicated in sending signals to the hypothalamus in the brain (from where the release of hormones is controlled) are maximally sensitive to light at about 480nm but there is some evidence that longer wavelengths of light could also influence alertness (in other words, the cones may also be involved). Here is one of my own papers on this topic:

Lin J & Westland, 2020. Effect of long-wavelength light on electroencephalogram and subjective alertness, Lighting Research and Technology, 52 (6), 763-774.

There is already growing research into the use of light and light-related products to help us to sleep better. As public awareness of this issue grows it is inevitable that interest in to this topic will increase. Perhaps such products could be used to mitigate the effects of poor sleep in situations such as the one I was in last week.

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