Parents have been urged to let their toddlers keep napping after research suggests it is vital for brain and memory development.
Some toddlers stop napping as early as age two while other children as old as five still want some daytime kip.
US researchers found have been looking at the hippocampus, the part of the brain that has a major role in learning and memory.
Their previous revealed a difference in the development of the hippocampus for children who nap and those who have stopped.
Prof Rebecca Spencer, of the University of Massachusetts Amherst, said: “When little kids are napping, they consolidate emotional and declarative memories, so then you ask yourself, when this is such an important time of learning, why would they transition out of napping if napping is helping learning? Why not just keep napping?”
Researchers said that when young children have an immature hippocampus, it reaches a limit of memories that can be stored without them being forgotten, triggering the need for sleep.
Napping then allows memories to move to the brain’s cortex, freeing space for more information to be stored in the hippocampus.
Prof Spencer said: “When the hippocampus is inefficient it’s like having a small bucket. Your bucket is going to fill up faster and overflow and some memories will spill out and be forgotten.
“That’s what we think happens with the kids that are still napping. Their hippocampus is less mature, and they need to empty that bucket more frequently.”
When the hippocampus is more developed, children can move away from taking naps because their hippocampus has matured to a point that their “bucket” will not overflow.
Forcing children to stop taking naps “could lead to suboptimal learning and memory”, she added.
The findings are published in the Proceedings of the National Academy of Sciences.
