Sleep the “Optimal” Amount to Avoid Sick Days

Do you often miss work because you are sick? If so, you might need to adjust your sleep schedule. Research from a study supported by the National Institute for Health and Welfare, the Academy of Finland, and the Finnish Work and Environment Fund found that people who slept too little or too much missed more work days due to sickness than their colleagues. The study suggests that the optimal sleep duration is between seven and eight hours each night.

The researchers used a nationally representative survey to gather data, surveying 3,760 men and women in Finland. At the outset of the study, the participants were between 30 and 64 years old. The researchers used a questionnaire to learn about participants’ sleep habits. Physicians in the field conducted physical examinations of the participants to learn about their health. The researchers also obtained data from the Social Insurance Institution of Finland, which helped them track sickness-related work absences. The average follow-up period for study participants was seven years.

Sleeping between seven and eight hours is associated with the lowest risk of missing work because of sickness. The researchers identified 7 hours and 38 minutes as the optimal sleep length for women and 7 hours and 46 minutes as the optimal sleep length for men. People who slept more than nine hours or less than six hours each night had a much higher risk of sickness-related work absences. People who slept less than five hours or more than 10 hours were absent from work 4.6 to 8.9 days more than people who slept for the optimal duration.

The findings demonstrate that sleep is an indicator of overall health. The researchers suggest that, if employers and the Finnish government could fully address sleep issues, the direct costs of sickness-related work absences could decrease by as much as 28 percent.

“Insufficient sleep—due to inadequate or mistimed sleep—contributes to the risk for several of today’s public health epidemics, including cardiovascular disease, diabetes, and obesity. Getting at least seven hours of nightly sleep is a key to overall health, which translates to less sick time away from work,” stated American Academy of Sleep Medicine President Dr. Timothy Morgenthaler.

This research is published in the journal Sleep.