The study took a look at 3,760 men and women 30 to 64 years old in Finland working at any time in the prior year. Their sleep characteristics were determined by questionnaire and health measures were derived from physical examination conducted by field physicians. Data for work absences due to sickness were gathered from the Special Insurance Institution of Finland, which tracks all sickness absences lasting more than 10 days. The average follow-up period was seven years.
The results published in the September issue of the journal Sleep - showed:
- The risk of an extended absence from work due to sickness rose sharply among those who reported sleeping less than 9 hours per night.
- The optimal sleep duration with the lowest risk of sickness absence from work was between seven and eight hours per night seven hours, 38 minutes for women; seven hours, 46 minutes for men.
- Insomnia-related symptoms, early morning awakenings, feeling more tired than others, and using sleeping pills were consistently associated with a significant increase in workdays lost due to sickness.
Optimal sleep duration should be promoted, as very long and very short sleep indicate health problems and subsequent sickness absence, said Tea Lallukka, Ph.D., principal investigator and specialized researcher at the Finnish Institute of Occupational Health. Those sleeping five hours or less, or 10 hours or more, were absent from work every year for 4.6 to 8.9 days more, as compared to those with the optimal sleep length. Insomnia symptoms should be detected early to help prevent sickness absence and deterioration in health, well-being and functioning. Successful prevention of insomnia not only promotes health and work ability among employees, but it can also lead to notable savings in reduced sickness absence costs.
Insufficient sleep due to inadequate or mistimed sleep contributes to the risk for several of todays public health epidemics, including cardiovascular disease, diabetes and obesity, added Dr. Timothy Morgenthaler, president of the American Academy of Sleep Medicine and national spokesperson for the Healthy Sleep Project.
The Sleep Well, Be Well campaign was launched earlier this year to increase awareness of the importance of sleep as one of the three pillars of a healthy lifestyle. The campaign is a collaboration between the Centers for Disease Control and Prevention, American Academy of Sleep Medicine, Sleep Research Society and other partners.
Sleep Loss And Brain Size
Another recent study on sleep published in the September issue of Neurology states that sleep difficulties may be linked to faster rates of decline in brain volume. The study found that sleep difficulties were linked with a more rapid decline in brain volume over the course of the study in widespread brain regions including within frontal, temporal and parietal areas. It also found that results were more pronounced in people over 60 years old.
The study involved 147 adults between 20 and 84 years old and the researchers examined the link between sleep difficulties having trouble falling asleep, staying asleep at night, brain volume. All participants underwent two MRI brain scans with an average of 3.5 years apart before completing the sleeping habits questionnaire. Thirty-five percent of the participants met the criteria for poor sleep quality and scored an average of 8.5 out of 21 points on the sleep assessment which looked at how long people slept, how long it took them to fall asleep at night, use of sleeping medications, as well as other factors.
It is not yet known whether poor sleep quality is a cause of consequence of changes in brain structure, said Claire E. Sexton, study author with the University of Oxford in the United Kingdom. There are effective treatments for sleep problems so future research needs to test whether improving peoples quality of sleep could slow the rate of brain volume loss. If that is the case, improving peoples sleep habits could be an important way to improve brain health.