A new study suggests that American adults who usually sleep fewer than 6 hours a night are more likely to have poor health habits than those who sleep 7 to 8 hours. The findings also suggest a similar poor pattern of health behaviours for those who usually sleep 9 hours or more. However, the authors were keen to stress that the finding do not prove that too much or too little sleep causes poor health behaviours, or the other way around. More research would be needed to investigate causes, they said.
The study, which is based on a national survey of a representative sample of US adults, was conducted by Charlotte A Schoenborn, and Patricia F Adams, from the Division of Health Interview Statistics at the US Centers for Disease Control and Prevention, and published on the National Center for Health Statistics – Health E Stats website on 7th May 2008.
The results showed that people who slept fewer than 6 hours were more likely to have a cluster of unhealthy behaviours such as being physically inactive in their leisure time, more likely to consume five or more alcoholic drinks a day, more likely to smoke, and they were also more likely to be obese. And they showed that adults who slept 9 hours or more, were also at increased risk of engaging in the same unhealthy behaviours, said the report.
What interested the authors the most, said Schoenborn, was the breadth of the findings. She said that:
“It seems to be across all these behaviors that sleep is associated… we don’t know which direction the associations go, what’s causing what, but we do see a clustering of these unhealthy behaviors and it suggests that we need to be dealing with these as a group rather than one at a time.”
Schoenborn explained that they found only 18 per cent of people aged 18 and over who slept between 7 and 8 hours a night currently smoked cigarettes, compared to over 30 per cent of adults who had fewer than 6 hours sleep. “That is a very large difference,” said Schoenborn.
Another large difference was in obesity, where they found one third of adult Americans who slept fewer than 6 hours a nights were obese, compared with only 22 per cent of those who slept 7 to 8 hours.
The authors wrote in their conclusions that the links between sleep and other behaviours are not straightforward, and it is not possible to say whether the sleep pattern causes the poor health behaviour, or the other way around, or whether something else links the two, because the study was a cross-sectional survey.
More research would have to be done to investigate the causes, they said, and to identify other factors such as poverty and level of education, that might also play a role in influencing sleep and other behaviours.
However, despite these limitations, the authors said their findings show how important it is that doctors and health practitioners discuss obesity and risky health behaviour such as smoking, use of alcohol and lack of exercise, when patients consult them about sleep problems.
Schoenborn said the public health message coming out of this study would be to encourage people:
“To look at their total lifestyle — including sleep — and don’t diminish the importance of sleep.”
“It is very important and it is something we just dismiss and say we’re tired but it really can affect your overall well-being,” she added.
“Sleep Duration as a Correlate of Smoking, Alcohol Use, Leisure-Time Physical Inactivity, and Obesity Among Adults: United States, 2004- 2006.”
Charlotte A. Schoenborn, M.P.H., and Patricia F. Adams, Division of Health Interview Statistics.
CDC, National Center for Health Statistics, Health E Stats, 7th May 2008.
Sources: CDC.
Written by: Catharine Paddock, PhD