woman helping elderly woman out of bed
Julie Hambleton
Julie Hambleton
March 22, 2024 ·  5 min read

The Startling Connection Between Bedtime and Dementia Risk

Alzheimer’s disease, a form of dementia, ranks among the top ten leading causes of death in the US. Recent research suggests that the time spent in bed and bedtime habits may significantly impact the risk of dementia, particularly among individuals aged 60-74. Previous studies have already emphasized the vital role of sleep quality in memory and dementia risk, highlighting the critical link between sleep and overall health, encompassing conditions like heart disease, stroke, depression, and obesity. The eye-opening connection between bedtime and dementia risk has prompted further exploration into the intricate relationship between sleep patterns and cognitive decline.

Bedtime and Dementia Risk: The Study

A groundbreaking study published in the Journal of the American Geriatrics Society involved researchers from China, Sweden, and the UK. The scientists analyzed the sleep data of 1,982 Chinese individuals with an average age of 70. None of the participants displayed dementia symptoms at the study’s inception. However, over an average period of 3.7 years, 97 individuals (5%) were diagnosed with dementia according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. Surprisingly, individuals aged 60-74 were found to be the most affected, with men exhibiting a higher risk compared to women. This is contrary to many previous studies that have indicated a higher dementia risk in women. (1)

The Findings

One of the notable findings of the study was the correlation between longer time spent in bed and increased dementia risk. Participants who spent more than 8 hours in bed were significantly more likely to exhibit cognitive decline during a Mini Mental State Examination (MMSE). This is a test commonly used to assess cognitive impairments. Experts explain that as individuals age, they experience a fragmentation of sleep stages, potentially leading to a diminished quality of sleep. This decline in sleep quality may require older adults to spend more time in bed to compensate, underscoring the importance of monitoring sleep patterns in relation to dementia risk.

Moreover, the study highlighted the timing of bedtime as a key contributing factor to dementia risk, with early-mid evening hours being deemed the riskiest. Surprisingly, researchers observed that advancing bedtime by just one hour before 10 pm was associated with a 25% increased risk of dementia. Researchers suggested that earlier bedtimes could be driven by disruptions in the circadian rhythm, meaning that age-related changes in the brain’s sleep regulation processes could also play a crucial role in dementia risk.

Plenty of Factors Affect Sleep as we Age

Further insights from experts in the field have underscored additional factors that can influence sleep patterns and dementia risk among older adults. Medical conditions like depression, heart disease, and diabetes, and the medications used to treat them, can increase tiredness and alter sleep requirements. The study also identified sundowning, a common phenomenon in older individuals prone to dementia. This is where confusion and disorientation tend to peak in the evenings, potentially affecting bedtime patterns.

The Study’s Limitations

While the study sheds light on the intricate relationship between sleep habits and dementia risk, it is essential to acknowledge the study’s limitations. Time spent in bed (TIB) does not always reflect actual sleep duration, with sleep quality also playing a crucial role in cognition and dementia risk. Quality of sleep, particularly the presence of deep sleep, is known to significantly impact memory function. Additionally, experts caution that the observed associations between sleep patterns and dementia risk do not establish a direct cause-and-effect relationship.

Read More: If You Do This While Cooking, It May Be An Early Sign Of Dementia

Lack of Sleep Also Contributes to Dementia Risk

Moreover, another study led by Dr. Séverine Sabia of Inserm and University College London has established that lack of sleep can also contribute to the development of dementia. This revelation further underscores the multifaceted relationship between sleep, cognitive health, and the risk of debilitating conditions like dementia. (2)

What Is Healthy Sleep?

The recommended amount of sleep for adults aged 24 to 64 is seven to nine hours per night. For those aged 65+, that recommendation changes to seven to eight hours. Duration, however, isn’t the only indication of quality sleep. It is important that those sleeping hours are uninterrupted, so that you can properly complete sleep cycles. Furthermore, it is important that your sleep routine is aligned with proper circadian rhythms, which are largely dictated by light and darkness. This is why you generally feel better when you go to bed before midnight and wake up in the morning, as opposed to going to bed sometime in the early morning and sleeping until noon. (3)

Sometimes it can be hard to tell if you are sleeping well. A good indication is how you feel in the morning when you wake up. After a good night’s sleep, you will feel refreshed, awake, energized, and ready to take on the day. A poor night’s sleep will leave you groggy, making it hard to get out of bed. You will also be more likely to feel moody, anxious, irritable, and have sugar cravings.

How To Get A Good Night’s Sleep?

If you are struggling to get a good night’s sleep, it may be time to make some changes. Here are some tips for getting better sleep:

  1. Create a bedtime routine. This can help signal your body that it is time to go to sleep and make falling asleep easier.
  2. Avoid caffeine, nicotine, and alcohol before bed. Caffeine, in particular, should not be consumed any closer than 4 hours before bedtime, with 6 hours being even more ideal. These substances can interfere with your sleep cycle and make it harder for you to fall asleep or stay asleep.
  3. Get regular exercise during the day. This will help tire out your body so that when it comes time to go to bed, you will be ready for sleep.
  4. Keep your bedroom dark, quiet, and cool. This can help you fall asleep faster and stay asleep longer.
  5. Avoid using electronics before bed. The blue light emitted by screens can interfere with melatonin production in your body, which makes it harder for you to fall asleep or stay asleep.

The Bottom Line

The research exposing the surprising connection between bedtime and dementia risk highlights the importance of monitoring sleep patterns, particularly in older adults, to mitigate cognitive decline and reduce the risk of dementia. While more research is necessary to further explore the intricacies of sleep’s impact on cognitive health, the study underscores the critical role of sleep quality and bedtime habits in maintaining brain function and overall well-being.

Both these studies provide valuable insights into the importance of healthy sleep habits in promoting brain health and reducing the risk of dementia. By understanding the profound impact of bedtime and sleep quality on cognitive function, individuals can prioritize adequate rest to safeguard their mental well-being and potentially lower the risk of debilitating conditions such as dementia.

Read More: There Are 8 Kinds of Dementia. Here’s How to Recognize Them, According to Experts


  1. Associations of sleep timing and time in bed with dementia and cognitive decline among Chinese older adults: A cohort study.” AGS Journal. Rui Liu MD, et al. September 21, 2022.
  2. Lack of sleep in middle age may increase dementia risk.” NIH
  3. Understanding the Connection Between Sleep and Dementia.” Harvard Pilgrim