It may have seemed earlier this month that the British press was focusing only on the News Corps phone-hacking story (or Kate and Will’s trip to Los Angeles), but, believe it or not, other articles were also being written, published, and talked about across the pond during that period.
One that caught my attention was a Guardian article on the health importance of our circadian rhythms. These are the internal “clocks” that set the timing of all our biological functions, such as the daily rise and fall of such things as blood pressure, body temperture, alertness, hunger, mood, sexual urges, and much, much more.
I co-authored a book on this topic many years ago, when the field was relatively new, so it’s always interesting to catch up on the latest research. In the Guardian article, Russell Foster, a professor of circadian neuroscience at the University of Oxford, mentions some of the more recent (and more consequential) scientific findings in the field. He describes, for example, how scientists now know that although we have a “master pacemaker” that resides in a cluster of neurons deep within the brain’s hypothalamus, all the other cells in our body also express clock genes and proteins.
That master pacemaker, therefore, doesn’t perform alone, but acts instead like “a conductor of an orchestra regulating the timing of the multiple and varied components of the ensemble,” writes Foster.
Circadian scientists have also recently discovered a new type of light receptor in the eye that is highly sensitive to the blue part of the light spectrum — the light that permeates the sky at dawn and dusk.
The receptor is thus perfect, writes Foster “for adjusting the internal clock to the natural light/dark cycle. Remarkably, even in animals and people in whom the rods and cones used for vision have been completely destroyed and who are otherwise totally visually blind, the [photosensitive cells in the receptors] can still detect light to shift the circadian clock.”
But, as Foster also notes, the more we discover about out biological clocks, the more we also learn about the mental and physical health problems that can develop when the clocks become desynchronized.
The more we learn, too, about how our modern 24/7 lifestyles contribute to that health-destroying desynchronization. Yet, we — as individuals and as a society — seem unwilling to address this problem.
Foster issues a warning of sorts:
“The introduction of electricity and artificial light in the 19th century and the re-structuring of work times have progressively detached us from the solar 24-hour cycle of light and dark. The result is disruption of the circadian and sleep systems.
“Such disruption results in performance deficits including increased errors, poor vigilance, poor memory, reduced mental and physical reaction times and reduced motivation. Long-term sleep and circadian rhythm disruption might contribute to chronic conditions such as diabetes, obesity and hypertension. Furthermore, obesity is strongly correlated with sleep apnea and hence additional sleep disturbance. Under these circumstances, the result can be a dangerous positive feedback loop of obesity and sleep disturbance.
“Humans have embraced the freedom to do what we want, when we want. Our 24/7 society has invaded and subjugated the night, an apparent victory of civilisation over nature. But the reality is that our society is replacing a biological order, honed by millions of years of evolution, with an illusion.
“Disrupting sleep and circadian rhythm impairs our brains and that drives many of us to substitute the rhythm normally imposed by internal time with daytime stimulants such as coffee, and nighttime sedatives such as alcohol — or worse. Such agents provide only the crudest mimic of the natural cycle of activity and rest.
“We have not achieved liberty, we have created a 24/7 tyrant.”
You can listen to Foster talk about the science of circadian rhythms — and the crucial role that a good night’s sleep plays in keeping those rhythms synchronized — in a 30-minute podcast interview with Guardian reporter Alok Jha.