As you can probably guess, long working hours can have negative health effects. Studies to date have shown that putting in long hours at work is associated with reactions by the cardiovascular and immunologic systems, sleep disturbances, depression, and obviously, fatigue and an overall unhealthy lifestyle.

On a different topic, there have been research studies in recent years showing that certain factors present in midlife cause one to be at increased risk for dementia later in life. One of the risk factors for developing dementia in our later years is the presence in our middle years of a decline in mental functioning. This means that if some of our mental faculties have already begun to go downhill when we are middle-aged, then we are at a greater risk for developing dementia when we get older than those people whose mental capacities are stable in midlife.

In a recent multicenter study* – done and analyzed in London, Finland, the US, and France – researchers examined, in middle-aged people, the association between long working hours (ie, working overtime, or greater than 40 hrs/week) and a decline in mental functioning (also known as a cognitive decline).  A group of five cognitive tests was administered to 2,214 middle-aged British civil servants at baseline and then five years later. Compared with working 40 hours/week, working 55 hours/week and more was associated with a decline in two of the tests over time, including a test of reasoning ability.  This means that those people who worked more than 55 hours/week during the five years of the study suffered from a decline in their ability to reason shown by their test results at the end of the five years. 

Of note, the many factors which could potentially affect these results were taken into consideration (controlled for) in the analysis including: physical diseases, education, occupational position, sleep problems, psychosocial stressors, and health risk behaviors.  There were several limitations to the study, such as the fact the number of work hours was self-reported by the participants which is dependent on the person’s ability to recall accurately, and that this study included only civil servants, and thus does not represent the entire working population. 

Since we know from other studies that the presence of cognitive decline in midlife is a risk factor for later dementia, it’s very important that we continue to learn to what are risk factors for an early-onset of decline in our mental capabilities. This study suggests that – in midlife – continued long working hours (in this case, greater than 55 hours per week) are associated with decreasing mental functioning over time.

Something to think about, right?

*[American Journal of Epidemiology. 2009; 169(5): 596-605.]