Sleep during the early stages of urbanisation

This week, I publised an article entitled Comparison between an African town and a neighbouring village shows delayed, but not decreased, sleep during the early stages of urbanisation in the journal Scientific Reports. The article is Open Access, which means it is freely available for all to read.

I hope the research has contributed to the discussion on artificial light, urban lifestyles and sleep and that other researchers find it useful. But in this post, I want to reflect on the background to the story – how the research came about and what happened when it got some publicity.

The results and conclusions

To start, let’s just be clear about what my research showed. The research presented the following main results:

  1. Sleep and activity timing is delayed in a small town compared to a neighbouring village.
  2. The delay in sleep timing associates with the amount of light participants were exposed to in the hours after sunset – i.e. the amount of artificial light. More artificial light, later sleep and activity timing.
  3. People living a rural lifestyle in the village were exposed to more bright light during the day than people in the small town.
  4. Total duration of sleep did not differ between the town and the village – though the town residents went to bed an hour later, they also were able to get up an hour later.
  5. Calculated measures of sleep quality (such as the proportion of time spent asleep compared to total time in bed, and the number of nighttime awakenings) were poorer in the village than in the small town.
  6. Villagers lifestyles, which included poorer quality of beds, more physical activity, more people sharing a sleeping space, more families keeping livestock near their homes, associated with poorer sleep. The greatest influence on this sleep quality was type of bedding.

We argue (as you can see in the paper) that these results suggest that urbanisation does not directly cause sleep loss, in terms of duration or quality. As hypothesised elsewhere, electrification associates with later sleep timing, but it doesn’t automatically result in shorter sleep. This is because in this context, participants were able to get up later to compensate for the later bedtimes, which isn’t always possible in the Western world. The sleep quality results suggest that urbanisation can be beneficial to sleep: urbanisation come a suite of lifestyle changes that allow people to sleep more comfortably. Perhaps when urbanisation is taken to further extremes, like the mega cities of the world, then urbanisation can be disruptive to sleep, but in the initial stages it may be a good development.

How the research came about

I spent two and a half years living in northern Mozambique, partly for my wife’s work and partly because it’s something my wife and I have always felt we should do. I, a trained research scientist with an interest in science communcation, was a bit out of place job-wise in rural Mozambique, but I got stuck in with a few things including running a TReND in Africa course on scientific communication (see here for a report). But I was really searching for a way to do some research. Luckily, at the December 2015 meeting of the UK Clock Club, I met Kieren Egan and Malcolm von Schantz of the University of Surrey, who were presenting work on sleep in communities very similar to those in which I was spending all of my time. After a quick lunch chat at the meeting and a few emails later, we had organised a small study of sleep and activity in my region of Mozambique, which I was going to conduct in the last three months of my time there.

It was a fairly ambitious project: I needed to collect activity monitor data from 150 or so Mozambicans to build up useful numbers, and before collecting any data we needed to twice translate (into Portuguese and Chichewa, the local language) a simplified questionnaire that could supplement the objective data from the activity monitors. Importantly, a small, international team was gathered by Malcolm which provided the equipment (15 wrist watch-style activity monitors) and support (scientific background and ethical approval) to give me the tools I needed to collect all this information as the field researcher. I already had good friends in Milange who could help me gain access to the communities, including Domingos Baulene and Ivo Matapule, without whom I, as a European, would have struggled to get permission to work in the rural areas and would have struggled to recruit the volunteers I needed. Domingos and Ivo helped me choose a rural community that would be open to enter the study and helped organise the necessary meetings with local chiefs. Once we had had these meetings, we were ready to collect data and when I arrived back in Mozambique in May with my 15 activity monitors, the project could start.

What followed was a fortnightly rotation of the watches, as each watch would be with a volunteer for two weeks, recording their activity and exposure to light and temperature. I had enough time to keep a day in between each 14-day period to charge them (if the electricity was on!) and download the data. At the start of each 14 days, I would meet the volunteers in a convenient place (often my house in our neighbourhood in Milange, and near the chief’s house in the village areas), explain my project in Portuguese or in Chichewa with the help of Ivo or Domingos, read and get signatures consent forms (or verbal consent for those who were unable to write), explain the activity monitor and how to look after it, and also conduct the questionnaire. These meeting days were tiring – not only the effort to speak in Portuguese and discuss my scientific proposal in understandable terms, but also the uncomfortable travel on unmade roads to the rural areas, which were up to an hour and a half on the back of a 50cc motorbike (cramped for someone of 1.90m).

Amazingly, at the end of the three month period I had all 15 activity monitors back with me and still functional, and 150 two-week recordings of activity and sleep patterns ready to be analysed. My wife and I left Milange just under a week after the end of data collection, and subsequently went on holiday for a few months. Back in Surrey, I had time and a mentor who allowed me to process the data, gather thoughts from colleagues, and write a paper, which eventually was accepted into a journal. A long and winding road to publication!


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