A study from the University of San Francisco, California (United States) reveals that long naps are linked to a high probability of suffering from Alzheimer’s. An excessive nap therefore can be an alarm symptom and not a cause of the disease.

“The main lesson is that if you used to not take naps and notice that you are now starting to feel more sleepy during the day, it may be a sign of declining cognitive health,” says Professor Dr Yue Leng.

The study was conducted with more than 1,000 people, with an average age of 81 years. Of the participants, 76% had no cognitive disability, 20% had moderate cognitive disability, and 4% had Alzheimer’s.

Those participants who napped for more than an hour a day had a 40% higher risk of developing Alzheimer’s than those who slept less than an hour.

In addition, insomnia, unusual sleep patterns and poor sleep quality are known to be associated with senile dementia.