Though poor sleep can be linked to a wide range of health problems, does that include obesity?

Certainly, people who are obese often develop issues with obstructive and central sleep apnea, the two most common sleep disorders, as well as related health problems such as Type 2 diabetes, heart disease, and osteoarthritis. In fact, US health surveys indicate that 30 percent of employees report insufficient sleep with an equivalent number reporting problems with daytime sleepiness.  Given that many of these same surveys show that 22 percent or more of employees are obese while an additional 36.8 percent are overweight, it’s hardly surprising that recent research provides support for a sleep-obesity link.  

Unfortunately, while the link between poor sleep and obesity seems to exist, it’s still not clear how they can be related.  One hypothesis suggests that impaired sleep can affect the hormones that regulate how energy levels are regulated in the body.  Another hypothesis focuses on the impact that poor sleep can have on lifestyle behaviours such as diet and exercise, i.e., fatigue leading to less time spent exercising or eating sensibly.  

Considering the general shift away from labour-intensive jobs towards more sedentary work, getting the minimum amount of moderate-intensity exercise needed to stay healthy (roughly 150 minutes per week according to health guidelines) is becoming increasingly difficult for most people. If you add in the fatigue that comes from inadequate sleep, along with the problems associated with carrying excess weight,  it`s not surprising that poor sleep and obesity often go together.

A new study published in the journal Health Psychology examines the sleep/obesity link  in a sample of nearly nine thousand working Australian adults.   Christopher Magee of Australia’s University of Wollongong  and a team of fellow researchers used data taken from the Household, Income and Labour Dynamics of Australia (HILDA) Survey which has been underway since 2001.  The HILDA Survey has been collecting information on family dynamics, work, and health through face-to-face interviews and self-report questionnaires on more than 16,000 adults in a series of annual waves.  

Along with information on health and lifestyle factors,including body mass index (BMI) and waist circumference measures, physical activity levels, and general health history, the HILDA survey has recently incorporated different measures of sleep quality.   This includes average number of hours of sleep per night, how many times participants wake up at night, average length of time needed to get to sleep, etc.   Participants were also asked to rate their overall sleep quality, whether they used sleep medication or over-the-counter sleep aids, and whether they were prone to daytime sleepiness.

Results showed that the study participants fell into one of five different groups depending on sleep quality:

  • Poor sleepers - poor perceived sleep quality, frequent sleep disturbances at night, increased daytime sleepiness, greater use of sleep medications, problem snoring, and short sleep durations (six hours or less per night).   Approximately 20 percent of all participants fell into this category.
  • Frequent sleep disturbances – generally reporting good sleep quality overall but still reporting a high rate of sleep disturbances (waking up frequently at night and trouble getting back to sleep). This group accounted for another 19.2 percent of participants.
  • Minor sleep disturbances - reporting good sleep quality with occasional sleep problems such as difficulty falling asleep and waking up at night.  This was the largest group with 85.2 percent of all participants.  
  • Long sleepers - having good quality sleep with infrequent episodes of disturbed sleep.  Called long sleepers because of the high proportion of individuals reporting longer than average sleep hours.  Accounted for 9.6 percent of all participants.
  • Good sleepers – good quality sleep, very few sleep disturbances, few episodes of daytime sleepiness, able to sleep without the need for sleep aids, and averaging seven to eight hours a night. This is the second largest group accounting for 26. 7 percent of all participants.

Overall, poor sleepers had the highest BMI and waist circumference measures followed by the frequent sleep disturbances group and then the minor sleep disturbances group.   The good sleepers group showed the lowest BMIs followed by the long sleepers group.  The poor sleepers and frequent sleep disturbance group participants also showed the lowest level of physical exercise which appears consistent with the BMI and waist circumference results.   Interestingly enough, the long sleepers group also showed lower levels of physical exercise despite relatively good BMI /waist circumference scores though it is still unclear how this relationship can be explained.

As Magee and his co-authors point out, there is likely a two-way link between poor sleep and obesity.   While poor sleep might lead to obesity by affecting hormone levels and/or lifestyle factors, obesity can also lead to poor sleep due to sleep apnea, arthritis, and other obesity-related health issues.  Additional  research is definitely needed to learn more about how sleep quality and obesity are related but studies such as this one already demonstrate how poor sleep and obesity can both affect productivity in the workplace.

It also highlights the importance of workplace health programs to encourage better sleeping habits in workers.  While diet and exercise programs already exist, at least in some workplaces, the economic benefits of effective workplace programs to help workers dealing with sleep problems cannot be underestimated.

So how well did you sleep last night?   And what might this mean in terms of your overall health?

References

Magee, C. A., Reddy, P., Robinson, L., & McGregor, A. (2016). Sleep quality subtypes and obesity. Health Psychology, 35(12), 1289-1297.

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