Children's sleep behaviors linked to gray matter volume with implications for academic performance, IQ

Children who sleep better (that is, those who wake up less during night) and those who wake up earlier have more grey matter in their brains (specifically, in eight cortical regions and in the hippocampus), perform better academically, and have a higher level of intelligence (IQ).

This has been demonstrated by scientists from the Sport and Health University Research Institute (iMUDS) and the Mind, Brain and Behaviour Research Centre (CIMCYC)—both part of the University of Granada (UGR). The scientists are collaborating in the ‘ActiveBrains’ study led by researcher Francisco Ortega, which involves a sample of more than 100 overweight or obese children.

Their work, published in the journal Pediatric Obesity, reveals that the regions of the brain associated with sleep in children include: the temporal (inferior temporal gyrus and the fusiform gyrus), the parietal (superior parietal cortex, supramarginal gyrus, postcentral gyrus, and precuneus), the frontal (frontal–superior medial gyrus), and the subcortical (hippocampus).

Our research shows that sleep is associated with greater grey matter in some areas of the brain that are important for better academic performance and cognitive development.”

Jairo Hidalgo Migueles, researcher at the UGR’s Department of Physical Education and Sports and principal author of this work

This research highlights the importance of developing strategies to improve children’s quality of sleep (not only its duration) at the cognitive level in the various stages of child development.

An appropriate window of time

“Similarly, we found that waking up earlier was strongly associated with better academic performance. This result seems to indicate that the appropriate window of time must be ensured, from the time the child wakes up until the school day begins, thus ensuring good cognitive activation,” notes Hidalgo Migueles.

Among the most original aspects of this study is the fact that the authors performed an objective and highly detailed measurement of sleep through accelerometers built into smartbands that the children wore through the night.

The UGR scientists also obtained high-quality images of the brain activity of the schoolchildren using magnetic resonance imaging carried out at the CIMCYC.