Cognitive decline is something we all have to face as we age. The symptoms will be familiar to many of us. Our ability to carry out cognitive tasks as well as physical responses slows down. Our memories and our abstract reasoning decline.
In addition to how we interact with the world while awake, our sleep patterns also change as we get older. It is harder to fall asleep and harder to stay asleep. In addition to waking up more often during the night—on average, three to four times—we experience less deep, dreamless sleep. Thus, even if we sleep the same amount of time, we must spend more time in bed to do so, and we wake feeling tired and sleep deprived.
Are these negative effects just part of the aging process that we must accept, or is there anything we can do to help our minds function better and to get more restful sleep at night?
When we sleep poorly, our first impulse might be to try to knock ourselves out with medication. Besides the possibility of dependence, medications often do not actually give us better quality sleep. Instead of trying to bury our heads in the sand, we would be better served to understand why true restorative sleep is vital for our brain health and thus our overall health.
Restorative sleep is the type of deep, dreamless sleep that allows our brains to complete the biological work that “restores” us. As we age and our sleep patterns change, we typically receive less restorative sleep, which in turns aggravates the cognitive decline we are already experiencing.
Before we explore whether this vicious cycle can be broken, let’s learn more about how restorative sleep actually helps our brains function more healthily.
To understand why restorative sleep is so important, we must take a look at the two main functions of sleep: detoxing our brains and allowing for the consolidation of memory. Keep in mind that both of these functions don’t just require some restorative sleep—they require adequate amounts of restorative sleep.
Let’s take a more in-depth look at how our brains rid themselves of toxins. Time magazine reports that the main function of sleep is to clear our brains of toxins. Research on mice has shown that while we sleep, our brain cells are quite active, flushing out toxins that impair our memory and cognitive function. Over time, if these toxins are not released, the build-up can contribute to more serious health problems, such as Alzheimer’s.
A healthy brain clears itself of toxins and keeps many of our biological functions in balance. These do not simply affect our physical health but our mental health and mood as well.
Our brains must also consolidate memories in order to function well. New research shows that synapses, the connections between our brain cells, shrink during sleep. Though this study was done with mice, other evidence supports the idea that humans experience the same process. As we learn and make memories while awake, our synapses grow. While we sleep, most of these synapses shrink; the largest and strongest connections, however, do not. This means that restorative sleep allows the brain to eliminate connections that are less important and retain the most important ones.
When memories and neural connections that we do not need are wiped out, the memories and neural connections that we do need have the physical space to grow stronger. The connections that are largest and most established are maintained through night after night of this pruning process. This process allows us to recall important memories more quickly and retain knowledge in order to learn new things.
Knowing that adequate amounts of restorative sleep are required to rid the brain of toxins and other waste products and consolidate memory, we might ask ourselves what happens when we are not getting the restorative sleep we need. When toxins are allowed to accumulate, we suffer the effects of inflammation and increased chances of disease. Our cognitive functions also decline more precipitously. Our brains are not as adept at eliminating those connections that we do not need or strengthening those connections that we do.
What can you do to keep your brain as healthy as possible? First and most importantly, visit your neurologist, who will help you determine if you are receiving enough restorative sleep—and help you take steps to get back on track if not. As we have seen, sleep plays a vital role in your brain health—and your brain health must be maintained to live a healthy, positive life.