Study Suggests Decline In Cognitive Ability With Extreme Sleep Duration

F.J. Thomas

Sarasota, FL ( – Older workers who get insufficient – or too much – sleep may be have less mental acuity than those who get the proper amount of sleep, according to new research. According to data from the United Nations, in 2015, 12 percent of the population was over the age of 60. By 2050, it is estimated that this age group will comprise over one-fifth of the population. With the rise of an aging population, cognitive impairment is a growing concern, especially considering the correlated increase in aging workers.

It is well known how sleep can effect overall health and cognitive abilities. A long term study published this month in The Journal of the American Medical Association (JAMA) suggests that cognitive function should be monitored in those individuals that get less than 4 hours or more than 10 hours of sleep.

Beijing researchers from Peking University Clinical Research Institute, Capital Medical University, and Chinese Academy of Sciences reviewed data from the English Longitudinal Study of Ageing (ELSA) in the UK, and the China Health and Retirement Longitudinal Study (CHARLS) that included data on 28,756 participants. The Beijing researchers analyzed data from 20,065 participants with 9,254 from the ELSA study, and 10,811 from the CHARLS study.

The ELSA study questioned individuals who were aged 55 and older. Median age of participants in the ELSA study was 64.6 with over half at 55.9 percent being female. The starting age for the CHARLS study was 45 with a median of 57.8, and 50.2 percent male participants.

The ELSA study began with the first wave in 2002-2003. Follow up assessments were done every 2-3 years until 2017.The CHARLS study began in 2011 with follow up surveys done every 2 years until 2015.

Individual cognitive abilities in both studies were assessed on aspects of memory, executive function, and orientation. Scores were calculated based on results of several tests. A word recall test included immediate and delayed recall. With the animal fluency test, participants were asked to name as many animals as they could in 1 minute. The serial sevens test included counting backwards from 100 in increments of 7. Individuals also participated in an intersecting pentagon copying test, and a date orientation test that asked about days of the week, month, and year.

Researchers found that individuals who slept less than 4 hours or more than 10 hours scored much lower than the reference group who slept 7 hours per night. The results showed consistency across all demographics of health and education status.

News brought to you by