On August 11th, 2012, BBC radio 4 broadcast a programme called Night as part of its Forum series. There were three guests, and the programme started with Professor Russell Foster of Oxford University. Prof Foster is a neuroscientist specialising in circadian rhythms about which he made a series of points.
- The eyes have two functions: firstly, to see, and secondly, to detect environmental brightness. The light sensors in the eyes are plugged into the parts of the brain that regulate our body clock, including sleep and arousal patterns. During a 24 hour period, we all undergo a steady change in hormones such as cortisol and melatonin as a result of changing light levels, and these either wake us up or send us to sleep.
- It is the disruption to these light/dark sensors that cause jet lag, and we get over jet lag by exposure to the new day/night cycle.
- The visually blind are not necessarily body-clock blind – but to be body-clock blind would be like having constant jet lag.
- For those on long term night shift work, the assumption has been that their body-clock adapts, however Prof Foster has found that it doesn’t, even if they work the same shift for 20 years. And this means they constantly have to override the desire for sleep when they are at work.
- This has severe health issues attached – long term night workers have higher rates of cancer, heart disease and non-insulin dependant diabetes.
- Rather fabulously, Foster said we think of our need for sleep as an illness which we can cure; we are arrogant enough to think we can override our internal biology.
- Although there is considerable variation in circadian rhythms within the population, many people with mental health problems also have disrupted sleep/wake cycles – there seems to be a real link in the brain, so if these people prefer to be awake during the night, this is a contributory factor to their mental health troubles. Also, just as with shift workers, those with mental health problems and abnormal sleep/wake cycles are also predisposed to the same debilitating illnesses.
- Foster made the point that night shift workers say they feel alright, but when put under test conditions their performance is remarkably impaired, leading to many accidents, especially industrial ones.
There were two other guests on the show, the second being an artist, Rut Blees Luxemburg whose works are based on urban landscapes at night. And what came out of her discussion of her love of working long into the night was that the lack of sleep impairs the normal brain function, so there is a lack of the normal critical analysis which allows artistic ideas to bloom. There may well be enhanced perception when we are very tired, but this is still not the time to drive a car or operate machinery.
The third guest was Craig Koslovsky of the University of Illinois, who has just published a book about the history of street lighting in Northern Europe. Apparently street lighting emerged very rapidly: in 1660 there was no street lighting, but by 1700 it was established in London, Amsterdam, Dublin, Paris, Hamburg and Leipzig plus other smaller cities in the Netherlands. The main reasons for the rapid expansion of street lighting, he claimed, was partly to prevent crime, and people were equally concerned with slipping into a pile of horse manure they could not see. As the night lit up, people started to colonise the dark hours by going out to the theatre, the opera or to each other’s houses. As a result, meal times changed, moving later by 5 – 6 hours, with the chance to show prestige by dining at night by candle light instead of eating during the day, using free daylight.
This brought the final main comment from Russell that night workers have a huge incidence of stomach ulcers because our digestive tract is incapable of digesting food properly in the middle of the night when these workers are eating ‘lunch’. Which shows, I suppose, that the old phrase, ‘Breakfast like a king, lunch like a queen and dine like a pauper’ still holds true.
In conclusion, when trying to help a client with weight loss or to improve energy levels, the two initial things to get on track are digestion and sleep. What Professor Foster was saying about what he has found out about circadian rhythms shows that, no matter how much we wish it were otherwise, we are still daylight animals, with our bodys and brains designed to work at their best during the day. At night, we sleep.