A COMMON sleep habit may be an early sign of Alzheimer’s, a study shows.
Do you love a lie-in or a do you regularly feel exhausted from too little sleep?
Clocking in enough hours of shut-eye is important for long-term health, scientists at the University of Warwick said.
They cited recent research which urged adults to aim for roughly seven hours of sleep each night.
But going above or below this sleep sweet spot could put people at risk of worrying health issues, researchers warned.
People who sleep longer than seven hours may be more likely to suffer cognitive decline and diseases such as Alzheimer’s, they found.
Regularly sleeping less than seven hours could also bring on side effects, as short snoozers were more at risk of depression, heart disease and obesity.
Scientists described their findings – published in Nature Mental Health– as a “paradigm shift” for understanding the connection between sleep and health.
Led by Professor Jianfeng Feng, from the School of Computer Science at the University of Warwick, researchers analysed the sleep data of almost half a million adults in the UK aged between 38 and 73.
Participants were asked how many hours of sleep they tended to get each night.
Based on how they answered this question, researchers then split them into groups of ‘short’ and ‘long sleepers’ – people who slept fewer then seven hours and those that slept more.
Participants’ sleep habits were then examined alongside health outcome data, genetic information and brain scans.
Researchers found that having a lie-in was associated with diseases such as Alzheimer’s and schizophrenia.
But they noted that hitting snooze appears to be a symptom, rather than a cause, of these conditions.
Long-sleepers were more likely to show signs of cognitive decline, had higher inflammation and lower levels of ‘good’ cholesterol.
Also known as high-density lipoprotein (HDL) cholesterol, it helps remove other forms of cholesterol from the bloodstream is linked to a lower risk of heart disease.
Brain scans also showed that long sleepers had brain matter loss in areas associated with memory and known risk areas for degenerative disease, such as Alzheimer’s.
As for short snoozers, people who regularly clocked in fewer than seven hours of sleep were more likely to experience low mood and fatigue and suffer conditions like depression, heart disease and obesity.
They also tended to have worse muscle bone health and were most at risk of vitamin deficiencies like vitamin D.
Finally, brain scans showed that short sleepers have reduced brain matter in brain areas involved in emotion.
Alzheimer's disease symptoms
The first noticeable sign of Alzheimer’s disease is often memory problems.
People may have difficulties recalling recent events and learning new information.
Memory problems can make a person with Alzheimer’s more likely to:
- Forget about recent conversations or events
- Get lost in a familiar place or on a familiar journey
- Forget appointments or significant dates
- Become increasingly disorganised
This is because one of the first parts of the brain to be damaged in Alzheimer’s is the hippocampus, which has an important role in memory.
The person is much less able to form new memories, which means they often don’t remember things that have happened recently.
Their memories of events that happened a long time ago are not usually affected in the earlier stages.
People with the disease may also experience:
- Difficulty with concentrating on conversations, cooking a meal or knowing what day it is
- Difficulty with conversation and finding the right words for things
- Mood changes, such as anxiety or becoming more easily annoyed, sad or frightened
- Struggles with judging distances and seeing the outline of objects
Source: Alzheimer’s Society
Researchers said this might be a biological consequence of cutting sleep short.
They concluded that short and long sleep had “biologically distinct” effects and “their own genetic associations”.
These means the each side of the sleep spectrum weren’t “two extremes of the same process” – instead, they each had different effects on health.
Prof Feng said: “This study represents a paradigm shift in how we understand the relationship between sleep and health.
“Short sleep is often an underlying cause of health issues, whereas long sleep tends to reflect pre-existing conditions.
“These findings highlight the importance of personalised interventions to address the unique biological pathways of short and long sleepers.
“Our ultimate goal is to construct a comprehensive sleep health profile across the human lifespan, providing actionable insights for individuals at every stage of life.”
The study comes after researchers warned that your weekend sleep patterns could be hampering your immune system – making it harder to shift that spring bug.
The NHS recommends that adults aim to get between seven and nine hours of sleep each night.