Just 16 minutes of sleep loss can harm work concentration the next day

Have you had a less-than-stellar performance review lately? Do you daydream, or are you making bad decisions?

It might not be about your job but about your sleep. And it’s not all your fault.

We each study different aspects of health and aging. A recent study we conducted found that poor sleep may inhibit judgment and lead to off-task and distracting thoughts at work. Making sleep a priority can improve cognitive performance at work.

Less sleep, less concentration

Sleep loss of about a quarter of an hour can affect work performance. fizkes/Shutterstock.com
Using eight-day diary data from a sample of 130 middle-aged workers in a U.S. IT firm, we found that a previous night’s sleep characteristics predicted next-day “cognitive interference,” or the experience of off-task and distracting thoughts.

To measure this, we used a 5-point frequency (0=never to 4=very often) and averaged responses on nine items that measure the experience of off-task and distracting thoughts than usual. For example, one of the questions was “How often did you have thoughts that kept jumping into your head today?”

On days following shorter and poorer quality sleep than usual, workers reported more cognitive interference. Across the participants, sleeping just 16 minutes less than usual was associated with one additional point on the cognitive interference scale the next day.

The participants also reported that after experiencing more cognitive interference on a particular day, they would go to bed earlier and wake up earlier than usual due to fatigue.

The link between previous night’s sleep and next-day cognitive interference was more apparent on workdays, less on non-workdays. Perhaps participants have more opportunities for cognitive interference and less opportunities for sleep during workdays. The results suggest that putting a larger emphasis on optimizing sleep health will result in more effective work performance.

From this study’s results, we deduce that shortened sleep may reduce work productivity. Previous lab-based experimental studies have shown that sleep deprivation, such as restricting sleep duration to four or five hours has negative effects on performance in cognitive tests.

However, there has been a lack of observational studies examining the relationship between sleep and cognitive functioning in participants’ own daily lives. Our study adds empirical evidence that poorer sleep the night before work will result in slower mental activity, delayed decision-making and potentially an increase in mistakes.