Sufficient Sleep Reduces Sick Leave

Inadequate or disrupted sleep is thought to contribute to risks of cardiovascular disease, compromised immune health, and weight gain.  Tea Lallukka, from the Finnish Institute of Occupational Health (Finland), and colleagues analyzed data collected from a nationally representative survey of 3,760 men and women in Finland who had been working at any time in the prior year. Participants were 30 to 64 years old at the study’s start.  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 Social Insurance Institution of Finland. The average follow-up period was seven years.  Utilizing a novel data analysis method, the team found that the risk of an extended absence from work due to sickness rose sharply among those who reported sleeping less than 6 hours or more than 9 hours per night. Further analysis found that the optimal sleep duration with the lowest risk of sickness absence from work was between 7 and 8 hours per night: 7 hours, 38 minutes for women and 7 hours, 46 minutes for men.  Further statistical estimates found that the direct costs of sickness absence to the Finnish government and employers could decrease by up to 28% if sleep disturbances could be fully addressed. The study authors submit that: “This study highlights the need for prevention of sleep disturbances and promotion of optimal sleep length to prevent sickness absence.”