Inicio / Historico

Children who sleep better and wake up earlier have more grey matter and deliver superior academic performance

[Spanish version]

Researchers from the University of Granada are leading the ActiveBrains study,in which more than 100 overweight or obese children participated

The research shows that children who go to bed earlier and sleep better and have more grey matter than those with poorer-quality sleep, leading to better academic performance and higher 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,” explains 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.


Migueles J.H., Cadenas-Sanchez C., Esteban-Cornejo I., Mora-Gonzalez J., Rodriguez-Ayllon M., Solis-Urra P., Erickson K.I., Kramer A.F., Hillman C.H., Catena A., and Ortega F.B. (2020), ‘Associations of sleep with gray matter volume and their implications for academic achievement, executive function and intelligence in children with overweight/obesity’. Pediatriatric Obesity. Online:

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

Regions of the brain in which grey matter volume is associated with sleep characteristics in overweight or obese children. Children who enjoyed better-quality sleep also had a greater volume of grey matter in certain areas (marked here in red)

Children who sleep better (that is, those wake up less during the night) and also those who wake up earlier have more grey matter in the brain, deliver better academic performance, and have a higher IQ

Media enquiries:

Jairo Hidalgo Migueles

Department of Physical Education and Sports, Faculty of Sport Sciences, University of Granada