Yes, a lack of sleep can really make you ill! But why?

More than a century ago scientists proved sleep supports the retention of memories of facts and events. But now, 100 years on, they are taking it way beyond that, proposing that deep sleep may also strengthen immunological memories of previously encountered pathogens.

Studies in humans have shown that long-term increases in memory T cells are associated with deep slow-wave sleep on the nights after vaccination.

“Taken together, the findings support the view that slow-wave sleep contributes to the formation of long-term memories of abstract, generalised information, which leads to adaptive behavioural and immunological responses,” one of the researchers said.

“The obvious implication is that sleep deprivation could put your body at risk.”

He said many viruses can easily mutate some parts of their proteins to escape from immune responses.

“If too few antigen-recognising cells [the cells that present the fragments to T cells] are available, then they might all be needed to fight off the pathogen. In addition to this, there is evidence that the hormones released during sleep benefit the crosstalk between antigen-presenting and antigen-recognizing cells, and some of these important hormones could be lacking without sleep.”

Next they will tackle what information is selected during sleep for storage in long-term memory, and how this selection is achieved. In the end, this research could have important clinical implications.

The research was published earlier this week in Trends in Neurosciences, as part of a special issue on Neuroimmunology.

Do you think getting plenty of sleep helps you recover faster from illnesses and injury? How many hours a night do you find is optimal?