Friday December 12 2014
Later waking was associated with better sleep
A major new study of American workers has recommended “later start times to improve on health,” the Mail Online reports.
To improve people’s sleep patterns the research team suggested work start times could be moved later, such as 10am. This was just a suggestion, and was not backed up with any new evidence from this study itself.
This research didn’t actually look at any health effects of sleep, but explored possible reasons for why people might sleep less. Most of the findings seemed common sense, such as having to get up to go to work.
Still, fatigue appears to be a common problem. As our website reports in the Living with insomnia section one in three Britons suffers from poor sleep, with stress, computers and taking work home often blamed for the lack of quality slumber.
And two of the most widely visited topics on the NHS Choices website are “10 medical reasons for feeling tired” and “Why am I tired all the time?”
If you are struggling to stay awake during your morning commute it may be an idea to discuss if there is any possibility of flexible working times.
Where did the story come from?
The study was carried out by researchers from the University of Pennsylvania and was funded by the US National Institutes of Health and NASA.
The study was published in the peer-reviewed science journal Sleep.
One of the authors is on a paid science advisory council for Mars Inc (the chocolate bar people). The same person and a colleague are editors and deputy editors of the journal in which the article was published. None declare a financial conflict of interest.
The coverage in the Mail Online was accurate, although seemed more excited by the findings than we were. Claims that a lie-in “could dramatically improve your life” were not backed up by new evidence uncovered as part of this study.
What kind of research was this?
This was a secondary analysis of data collected from a previous cross-sectional survey.
The research team was looking for reasons why some people sleep less than others. They highlight that sleep is essential for memory consolidation and alertness, while lack of sleep is linked with poorer health.
Regular poor sleep puts you at risk of serious medical conditions, including obesity, heart disease and diabetes – it also shortens your life expectancy.
What did the research involve?
The research team analysed information on what people did each day, and how long they spent doing it, including sleep patterns. They compared the habits of short sleepers (less than 6 hours a night) with normal sleepers (6 to 11 hours) and longer sleeps (over 12 hours) to uncover possible reasons for the sleep differences.
The information was already collected for them as part of the “American Time Use Survey”. This gave them access to detailed information on the daily habits of 124,517 adult Americans over 15 years of age.
The definition of sleep in the study included a range of rest and napping type behaviours such as “dozing off”, “catnapping” and “getting some shuteye”. This is different from most studies recording sleep, which tend to ask how much sleep people get on average over the week and or weekends.
The analysis looked for links between sleep duration and the wide range of daily activities reported during the survey, such as going to work, socialising, self-grooming and watching TV.
The analysis was adjusted to reflect the general American population in terms of demographics and took account of where and when the surveys took place.
What were the basic results?
One of the main findings was that people slept less if they had to go to work. A good example of science confirming common sense. With every hour that work or education started later in the morning, people slept 20 minutes more.
Working multiple jobs was linked with the highest chance of sleeping less than six hours a night on weekdays.
Self-employed people were less likely to be short sleepers compared to private sector employees.
Short sleep was consistently linked to the following factors:
- being 25 to 64
- being a man
- having a high income
- being employed
How did the researchers interpret the results?
The researchers suggested: “Interventions to increase sleep time should concentrate on delaying the morning start time of work and educational activities (or making them more flexible), increasing sleep opportunities and shortening evening and commute times.
“Reducing the need for multiple jobs may increase sleep time, but economics disincentives from working fewer hours will need to be offset.
“Raising awareness of the importance of sufficient sleep for health and safety may be necessary to positively influence discretionary behaviours that reduce sleep time, including television viewing and morning grooming.”
This cross-sectional study highlights possible reasons why people might sleep less, most of which seem common sense, such as having to get up to go to work. The data were collected as part of a large cross-sectional survey in the US, but the findings are likely to be relevant here in the UK. The study does not provide any new information on whether, or how, poor sleep leads to poorer health, directly or indirectly.
The study did not have detailed information on some factors that affect sleep, such as alcohol or caffeine, or, as far as we could tell, the quality of sleep. Similarly, their definition of sleep, which included napping, was a little different to what you might expect. These limitations reduce the reliability of the findings but, in our view, are unlikely to affect the overall conclusions reached.
The researchers’ interpretation was that people’s sleep patterns may be improved if the working day started later, such as 10am, or was flexible. This was raised in the discussion but was not built on evidence collected from the study itself. Many work places will have such arrangements, but they may be practically difficult in many time-bound industries.
The study serves to point out possible solutions to low sleep hours. However, the solutions of less work, more rest and flexible hours may be somewhat at odds with current trends of economic development based on consumerist principles. The reasons people sleep less seem deeply entrenched in financial, cultural and societal pressures and changing these is likely to be challenging in increasingly globalised economies of the modern age.
The economist John Maynard Keynes famously predicted that by the early 21st century we would all be working just 15 hours a week due to efficiency gains through technology. How wrong he was.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.