Sleep apnoea – the condition where people temporarily stop breathing during sleep – can be scary. What’s more worrying is the link to Alzheimer’s Disease recently uncovered by researchers. Studies have suggested that people experiencing sleep apnoea also have higher odds of getting Alzheimer’s Disease. But why should this be the case? Let’s dig deeper.
Alzheimer’s Disease is a very common form of dementia, known to affect up to 70% of dementia sufferers. One of the biggest risk factors for developing the disease is ageing. Sleep apnoea also starts to become more common in middle age, and particularly in menopausal women. Obesity is also a common trend in sleep apnoea sufferers.
The link between Alzheimer’s and sleep apnoea has been suspected for a while by experts. Molecular changes occur in the brain for decades before symptoms of Alzheimer’s can be detected. Over time, amyloid plaques toxic to brain cells can accumulate in the brain – and they start in the same place and spread in the same way in the brains of both people with Alzheimer’s and people with sleep apnoea. And amyloid plaques are known to be indicators of Alzheimer’s disease. As well, the hippocampi (the part of the brain used for memory processing) is smaller in people with sleep apnoea, as well as in people with Alzheimer’s Disease. Sleep apnoea can adversely affect people’s memory – a symptom it has in common with Alzheimer’s Disease. Sufferers of sleep apnoea are also at a higher risk of developing dementia.
What’s unclear is whether the build-up of “tau” protein tangles in the brain is a marker for Alzheimer’s, or if this increased build-up causes the sleep apnoea. It’s possible that having Alzheimer’s Disease might predispose people to experience sleep apnoea, or that having sleep apnoea makes people more vulnerable to dementia and Alzheimer’s Disease. It’s like the chicken and egg conundrum. Or the two disorders may well play off each other, with each making the other worse. The connection is there, that’s certain; but how it actually works remains a mystery. However, confirming this connection allows researchers to move in new directions as they work towards developing treatments for Alzheimer’s sufferers.
And while these studies don’t shed any more light on what actually causes Alzheimer’s Disease, they still provide vital information. The upshot is that if you have sleep apnoea in mid-life, an Alzheimer’s diagnosis is more likely when you get older. Similarly, if you have Alzheimer’s, you’re also more likely to suffer from sleep apnoea than other people in your age bracket. Severe sleep apnoea is associated with a greater build-up of toxic plaque and protein tangles than a milder form of the condition.
Along similar lines, research has also found that when young and healthy men were deprived of just one night’s sleep, they had higher levels of biomarkers for Alzheimer’s Disease in their blood than when they had a full night’s sleep. Similar studies have produced the same results in those aged in their 50s and 60s. These findings highlight the importance of sleep at every age in maintaining healthy brain chemistry. While some amount of sleep deprivation might be expected throughout our lives, it’s more important than ever to try to regularly get seven to nine hours of quality sleep per night.
Sleep has an intrinsic role to play in removing proteins and waste products that accumulate in the brain during the day, and a lack of it can thwart this process. It’s thought that the brain might get less oxygen during episodes of sleep apnoea, causing stress to the brain. The body’s circadian rhythms might also be thrown off by the sleep disturbances caused by sleep apnoea. As well, interrupting the process of solidifying memories during sleep might lead to memory problems further down the track.
So, while having sleep apnoea doesn’t necessarily mean that you’ll also get Alzheimer’s, the risk is likely to be higher. It’s also worth noting that current sleep apnoea treatments such as continuous positive airway pressure (CPAP), relieve the symptoms of sleep apnoea, but are not thought to prevent the build-up of toxic plaque on the brain.
So, if you suffer from sleep apnoea, is there anything you can do to help prevent getting Alzheimer’s Disease?
As there is currently no treatment for Alzheimer’s Disease, it’s doubly important to treat any condition that might make symptoms worse or increase the chances of developing the disease.
The most important thing you can do is get lots of sleep (discover some handy steps to getting a better night’s sleep for older adults here. Get your sleep apnoea diagnosed and treated. Make sleep a priority, even if it means spending 9 hours in bed in order to get 7 – 8 hours of sleep. There are strong brain health benefits of getting plenty of sleep, which will help prevent cognitive decline and dementia. Sleep apnoea has been associated with a quicker decline in mental function, so there’s a good chance that treating sleep apnoea might slow down the progression of Alzheimer’s Disease – something that’s well worth doing.
Find out more about how to help prevent ageing from causing brain function decline here.
On a related note, find out how high blood pressure can damage your brain here.