How you slept last night is linked to the likelihood of developing Alzheimer's disease.

Just one night of poor sleep causes an increase in the brain chemical involved in Alzheimer’s disease, new research has shown.

Scientists out of Stanford University and Washington Medical School have discovered a spike in the levels of the chemical amyloi beta – the main component found in the brain plaques of Alzheimer’s patients – occurs in the brain following a poor night sleep.

Though dementia and lack of sleep have been connected before, this is the first study to show how one might lead to the other.

After just one bad night's sleep, the concentration of amyloi beta in the brain will increase and then return to normal.

However, the researchers suggest that continued sleep deprivation could lead to a build up of the substance in the brain and eventually result in memory loss.

"We think that perhaps chronic poor sleep during middle age may increase the risk of Alzheimer's later in life," the head of the Department of Neurology at Washington Medical School Professor David Holtzman told The Sydney Morning Herald.

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Amyloi beta is not the only offending substance. Another chemical, called Tau, was also found to increase after multiple nights of sleep deprivation.

This chemical has been shown to cause tangles in the brain's neurons and it too has been linked with Alzheimer's disease.

At the moment, more than 400,000 Australians are living with dementia and the disease is the second leading cause of death in the country.