My last few weeks have been spent in a deluge of podcasts, radio appearances and interviews, following the UK launch of Sleepless: Discovering the Power of the Night Self, my new book (and – excuse the brag – The Times Book of the Week!!).
Interestingly, almost every interviewer has approached the subject through their own lens, with some honing in on the spiritual nature of night, others on the remarkable benefits of night sky gazing, while some wanted to discuss the grieving and insomniac brain and others were more interested in how we become more creative at night. Mariella Frostrup wanted to talk about Margaret Thatcher’s infamous four hours of sleep and the frustrations of tossing and turning, and Clare Balding (with whom I night yomped over the South Downs) was interested in the way darkness nudges us into heightened states of trust.
All of which is to say that, thanks to so many insightful interviews, these subjects are still blooming and developing in my mind. There’s still time to sign up for our online launch next Wednesday (31 January) at 7pm, when Susan will be putting her own insightful questions to me. Sign up here to get the link.
And so I was intrigued to read recently that, come the winter darkness, our activity levels drop by 37%. In a poll of 2000 people, 75% blamed the cold while 57% were put off by the dark mornings and evenings (both of which I have come to love).
In the Northern Hemisphere, January is also the peak month for insomnia. And January 24th (just two days ago) is on record as consistently being the most depressing day of the year. Could there be a connection between our poor sleep, our low mood and our reluctance to venture outside? Or perhaps between poor sleep, seasonal affective disorder and a more sedentary indoors lifestyle? Or between the sheer volume of artificial light necessitated by short dark days and our gloomier mood and greater chance of broken sleep?
Prof Andrew Huberman certainly thinks so. In his podcast this week, he dug deeply into a large study on the mental health effects of getting insufficient light in the day and insufficient darkness at night. I wrote a blog post on this very study last year. Luckily, Huberman’s conclusion was the same as mine: we need as much outdoor light as possible during the day, and we need a decent amount of darkness at night.
‘Light is a potent stimulus’, said Huberman, adding that light at night raises the risk of major depression, bipolar disorder, psychosis and self-harm – but not anxiety.
This is an important study for us at the Age-Well Project because its 86,000 participants were all in their 50s and 60s. Moreover, when I discussed it with one of the authors, he told me that the findings were a little different for women. His next study (not yet published) attempts to unpick biological sex differences, but it’s possible that women are more light-sensitive. What does this mean?
It’s too early to say, but when I delved into other studies I found similar intimations: women are different at night. We sleep differently. We respond to sleep deprivation differently. We may have a greater need for darkness at night. We are biologically primed for sleepless nights (how else would the human race have survived?). Susan and I will discuss this, of course, but it reminded me of the huge challenge of disentangling epidemiological studies. In the course of writing Sleepless I reached out to many researchers and was astonished at how often critical factors had been ignored or overlooked, and how infrequently biological sex had been considered. This is changing now, thank goodness. The latest studies have found that women sleep differently according to their menstrual cycle, for instance. Previously women were often excluded from studies because researchers knew our constantly shifting hormones could mess up the data. Writing questionnaires that took such things into consideration was complex, time-consuming and expensive. Hence women have been omitted from hundreds and hundreds of studies.
When it comes to sleep studies, this has come at a high price. Although the latest investigation of dementia, published last month, lists the fifteen factors most likely to nudge the brain into early dementia – and sleep isn’t mentioned.
After studying the records of 365,000 people, the researchers concluded that the main risk factors for early dementia were: low socioeconomic status, social isolation, hearing impairment, stroke, diabetes, heart disease, orthostatic hypotension (a form of very low blood pressure), depression, Vitamin D deficiency, high levels of C-Reactive Protein (aka inflammation), having 2 APOE4 genes, a history of alcohol abuse, not drinking any alcohol, lower levels of formal education, and low handgrip strength (a marker of overall frailty).
What most struck me (other than the low place of smoking, diet, movement and air pollution, and the curious place of moderate alcohol as a preventative factor) were the words of its author: ‘In addition to physical factors, mental health also plays an important role, including avoiding chronic stress, loneliness and depression.’
But even a report of this magnitude needs to be scoured with a critical eye and considered alongside other reports. Things are not always as they seem. As I realised after scrutinising a recent sleep study which came with a headline about the dangers of being a Night Owl.
Night owls have an increased risk for developing type 2 diabetes and are more likely to smoke more, exercise less, and have poor sleep habits compared with their larkish counterparts, stated the study which investigated the self-reported chronotype of 60,000 nurses (all female, aged 45-52). The researchers found that women who woke later had a 72% greater risk of type 2 diabetes and were 54% more likely to ‘have unhealthy behaviours’ than early rising nurses. Oddly, a nightly glass of wine was considered ‘an unhealthy behaviour.’
But after adjusting for six lifestyle factors – diet, alcohol consumption, body mass index, physical activity, smoking habits and typical sleep duration – the link between being an owl and the risk of diabetes fell from 72% to 19%. Dig a little deeper, and we find that the association between a night owl chronotype and diabetes disappeared completely among an entire cohort of nurses. In fact it only applied to nurses who had worked night shifts for ten years – or nurses who had never worked a night shift. The authors concluded that night owls were more metabolically suited to night work and employees should be matched to circadian preferences. But a carelessly written headline would have created a very different picture.
The big confounder in many sleep studies, however, is the role of stress and depression. Is it the poor sleep or the stress that’s causing the poor sleep that leads to health problems?
So, you see the complexities involved in making assumptions. And yes, Susan and I will be discussing misleading headlines, stress and personal chronotype too (if we have time).
It’s January, so let’s end with a bit of good news: it seems that tomatoes and dark chocolate can lower blood pressure. Indeed, dark chocolate may also help reduce the risk of blood clots. Why not cook a few of the tomato-ey recipes on our site (search on ‘tomato’ in the ingredients list) and then knock up a batch of these delicious dark chocolate biscuits?
In the meantime, there may still be places at my forthcoming events:
Sunday Jan 28th – Sevenoaks Book Shop, Kent
Thursday Feb 1st – East Grinstead Book Shop, Sussex
Saturday Feb 3rd – Stony Words, Milton Keynes, Bucks
Saturday March 2nd – Red Lion Books, Colchester, Essex
Sunday March 3rd – Much Ado Books, Alfriston, East Sussex
Tuesday March 19th – Winstone’s Books, Sherborne, Dorset
Wednesday March 20th – Winstone’s Books, Frome, Somerset (link to come)
And there’s still a chance to win one of 3 copies of Sleepless over at my Instagram @annabelabbs. I’ll also be giving away a couple of copies at next week’s launch.
Note: in the picture above I’m wearing blue-blocking glasses (which I don every evening when I’m at home) to keep lights both dimmish and amber hued. More on these in a future post, but yes, my family find them hilarious!