How Poor Sleep Increases the Risk of Alzheimer’s Disease September 15, 2025 Most of us know how sluggish and forgetful we can feel after a bad night’s sleep. But mounting research shows that poor sleep isn’t just about feeling tired the next day – over the long term, it may increase the risk of Alzheimer’s disease.1 Alzheimer’s is the most common form of dementia, affecting nearly 50 million people worldwide.2 It’s a progressive brain disorder that causes memory loss, confusion, and difficulties with language, judgement, and problem-solving.2 While age is the strongest risk factor, how well we sleep throughout life also plays a surprisingly big role.2 What happens in the brain when we don’t sleep well? Sleep is not just downtime – it’s when the brain does vital housekeeping. During deep “slow-wave” sleep, the brain clears away waste products, including proteins like beta-amyloid and tau.2 These proteins are natural by-products of brain activity, but when they build up, they form sticky plaques and tangles that are hallmarks of Alzheimer’s disease.2 Studies show that poor sleep or too little deep sleep can accelerate this build-up.1 Older adults who spend less time in slow-wave sleep tend to have higher levels of tau in the brain.3 Even more striking, changes in amyloid and tau can begin up to 20 years before the first signs of memory loss, meaning sleep problems in midlife may quietly raise the risk of dementia decades later.3 The vicious cycle of poor sleep and brain health Sleep deficiency doesn’t only allow toxic proteins to accumulate. It also fuels oxidative stress and inflammation in the brain, raises stress hormones like cortisol, and lowers levels of protective brain chemicals that support neuron growth and repair.1 Over time, this reduces the number of synapses – the vital connections between brain cells – weakening the networks that underlie memory and thinking.1 Interestingly, it’s not just about how many hours we sleep but the quality of that sleep. Some studies found that people with early signs of Alzheimer’s actually slept longer, but their sleep was fragmented and lacked restorative deep stages.3 This meant their brains were not truly resting or repairing.3 Why middle age matters Research from both Harvard and European studies suggests that sleep patterns in midlife are particularly important. People who regularly slept six hours or less at ages 50, 60, and 70 were around 30% more likely to develop dementia later in life compared to those who averaged seven hours.4 On the other hand, very short sleep in older adults – fewer than five hours per night – has been linked to a doubled risk of dementia.4 Taking action Poor sleep can happen for many reasons: stress, shift work, insomnia, or medical conditions like obstructive sleep apnea. Since one in five Australians has sleep apnea – and most don’t know it – getting checked for underlying issues is crucial.5 If you’re struggling with poor sleep, talk to your doctor. Simple changes in sleep habits, managing stress, or treating underlying sleep disorders could help protect your brain for years to come. Prioritising good sleep is not a luxury – it’s an essential investment in long-term brain health. How Sove CPAP Clinic Can Help Founded in 2008, Sove CPAP Clinic has grown to become a leading provider of respiratory and sleep services and products in Australia, with over 60 clinics nationwide. Our comprehensive clinical team includes Respiratory & Sleep Specialists, Sleep Technologists, and CPAP Consultants, ensuring that you receive comprehensive and personalised care. All medical procedures, including sleep studies and lung function testing, are bulk billed to all Australians, with minimal wait time. If you would like to speak to a Respiratory & Sleep Physician, book a bulk-billed sleep study, or seek advice for your sleep apnea, you can reach us at 1300 76 29 39 or info@thecpapclinic.com.au. ALWAYS FOLLOW THE DIRECTIONS FOR USE. CPAP is used for Obstructive Sleep Apnea treatment. When considering whether a sleep study or CPAP is right for you, speak to your doctor. Medicare criteria and T&Cs apply. References Lv, Ya-Nan, et al. “Sleep Deficiency Promotes Alzheimer’s Disease Development and Progression.” Frontiers in Neurology, vol. 13, 14 Dec. 2022, https://doi.org/10.3389/fneur.2022.1053942. Sadeghmousavi, Shaghayegh, et al. “The Effect of Insomnia on Development of Alzheimer’s Disease.” Journal of Neuroinflammation, vol. 17, no. 1, 6 Oct. 2020, https://doi.org/10.1186/s12974-020-01960-9. Bhandari, Tamara. “Decreased Deep Sleep Linked to Early Signs of Alzheimer’s Disease.” WashU Medicine, 9 Jan. 2019, medicine.washu.edu. Budson, Andrew. “Sleep Well — and Reduce Your Risk of Dementia and Death.” Harvard Health, 3 May 2021, www.health.harvard.edu. Soenen, Stijn, et al. “Sleep Health Primary Care Clinical Resource.” Australian Journal of General Practice, vol. 53, no. 6, 1 June 2024, pp. 349–355, https://doi.org/10.31128/ajgp-03-23-6779.
