We already know that when we disrupt the sleep of mice, we affect their memory. We also know that amyloid beta (a marker for Alzheimer's) increases whilst we're awake - potentially putting insomnia sufferers at a greater risk of developing the disease.
Now a new study suggests that those who awaken more than five times every hour are more likely to have preclinical Alzheimer's disease.
The study looked at 100 men and women between 45 and 80 years of age. For two weeks, each participant wore a device that measured their sleep. They also completed sleep questionnaires and sleep diaries.
Study participants stayed in bed for around eight hours each night, sleeping for an average of six and a half hours. In total, a quarter of participants showed evidence of preclinical Alzheimer's disease. Those who woke up the most often were more likely than the others to show abnormal amyloid plaques (deposits found in the brains of those suffering from Alzheimer's).
Those who spent less than 85% of their time in bed actually sleeping were also more likely to show evidence of preclinical Alzheimer's.
These are just preliminary findings - and all we have here is an association; not a cause-and-effect. That being said, it's further evidence that sleep is hugely important to our overall health and that we need to address the prevalence of insomnia with urgency.