Seven hours of sleep a night and lots of reading — that seems to be the magic formula for keeping mentally alert into old age, according to the findings of a study out of Spain.

After analyzing the lifestyles of 245 seniors aged 65 and older, researchers from the CEU Cardenal Herrera University in Valencia, Spain, found that those who slept either too much or too little and abstained from brain-stimulating activities like reading were at increased risk of developing cognitive impairment.

According to the study, published in the journal Revista de Investigacion Clinica, seniors who slept more than eight hours or less than six, were 2.6 times more likely to suffer from cognitive impairment compared to those who got six to eight hours a night.

Likewise, the absence of brain-boosting activities such as reading contributed to cognitive decline. Those who admitted to not reading had a 3.7 times higher risk, while those who said they read occasionally increased their risk by 2.5 times.

Overall, 12 percent of the participants suffered from cognitive impairment.