Sleep and Cognition

Most people know that getting the right amount of sleep can help improve cognitive function. As a child, your parents probably assigned you a “bed time;” as a student, you were probably discouraged from pulling “all-nighters” and instead urged to get 8 hours of sleep. So why aren’t adults given similarly important guidance? What people might not know, but is becoming more evident based on developing research, is that poor sleep hygiene can lead to an increased likelihood of cognitive decline and dementia in older adults. This is because our brains are hard at work while our bodies rest, and the brain activity that occurs during sleep helps optimize cognitive functioning. Sleep habits and requirements may vary over the course of a lifetime, but the importance of proper rest for optimal functioning does not.

At ENRICH, our multi-disciplinary team of experts works to highlight the importance of brain-healthy habits that individuals can adopt to lower their risk for cognitive decline. More and more evidence points to adequate sleep as a requirement for optimal cognitive functioning. If good sleep can lead to high cognitive functioning, it’s natural to wonder if the converse is true: Does poor sleep lead to cognitive impairment, and are there long-term effects of chronic poor sleep for older adults?

Empirical evidence suggests that there are. Prospective sleep studies have found that participants with poorer sleep, defined in terms of quantity and quality, were more likely to develop dementia later in life. There are a few theories that may help explain this phenomenon:

  • A good night’s sleep helps preserve brain health by paving the way for the sleep-dependent memory consolidation that takes place during slow-wave and REM sleep. When this process is compromised on a regular basis, brain health and cognitive function begin to deteriorate.
  • Sleep helps clear the brain of the toxic protein beta-amyloid, which has been shown to accumulate in brains of individuals with Alzheimer’s disease. Chronic poor sleep may be partially responsible for the accumulation of beta-amyloid.
  • Chronic stress typically results in sleep disturbances. It is also associated with a variety of risk factors for dementia, including hypertension and diabetes. Therefore, poor sleep may indirectly contribute to the dementia process through the negative health outcomes that come with stress.           

Regardless of your age, your brain needs adequate sleep to function at its best. Whether your goal is short-term maximization of cognitive performance on an exam or long-term preservation of brain health, our recommendation is to strive for The National Sleep Foundation’s recommended duration of sleep. The National Sleep Foundation recognizes that there are individual and age-related variabilities in sleep needs. However, the following recommendations are given as general guidelines: 7-9 hours for adults aged 18-64 and 7-8 hours for adults ≥ 65.

There are dozens of ways to live a brain healthy lifestyle, including practicing good sleep hygiene. At ENRICH, we focus on the six habits that our research has shown to be the most impactful and modifiable. With our ENRICH calculator and guide for living a brain healthy lifestyle, we outline the six most critical brain healthy habits you can control. Learn about them by using ENRICH, a consumer-focused, multi-step set of tools that translate the best available science into straightforward information for individuals and families.