Sleep is like the ‘SAVE’ icon on your computer. When you sleep, memories become more solidly formed and stored inside your brain. Studies in both humans and animals show that when you lose sleep, even for just a few hours per night, you develop memory problems. (Imagine not pressing the ‘SAVE’ button and losing precious information). You can imagine then, how important sleep becomes for a brain trying to relearn and rewire after brain injury (Please see my post from Jan 2012 on ‘Sleep and Brain Recovery’ for more discussion).
So what aspects of sleep are most important; total hours of sleep, naps, how long it takes to go to sleep, waking up at night, or daytime sleepiness? A recent study published in Sleep Medicine (May 2012) followed 2012 people over the age of 65 for 10 years. The study, a partnership between researchers at University of Cambridge, UK and University of South Australia (Keage 2012), found that older people who take a nap during the day are two thirds less likely to develop cognitive impairment 10 years later. The authors describe napping as ‘protective’ against cognitive decline.
Furthermore, sleeping less than 6 hours each night doubled the risk of cognitive impairment over 10 years. People who reported daytime sleepiness had 2.5 times the risk of developing cognitive impairment 10 years later. The results of this study suggest that to preserve brain health over the long term you should sleep between 6 and 9 hours per night and have about a 60 minute daytime nap.
Why is sleep so important? Well, studies show that people who experience sleep deprivation for 24 hours have higher levels of stress hormones in the blood (See my post “Chronic stress and depression is bad for your brain” November 2012). They also make more errors on thinking tests (Joo and group, Journal Clinical Neurology 2012). People with chronic insomnia have significantly lower scores on tests of attention and concentration. They have impaired memory and thinking compared to people who sleep normally (Noh and group, Journal Clinical Neurology 2012) and what is most alarming is that people with insomnia have shrinkage of a very important cashew-sized section of the brain critical for forming memories called the hippocampus. During medical sleep studies, insomniacs who have experienced insomnia longer and who are more restless at night, have more brain shrinkage and more cognitive impairment. These are clearly NOT GOOD THINGS!! So pay attention to sleep. It is very likely that a good night’s sleep (or a daytime nap) can, not help maximize your recovery from a brain injury, but also promote a healthy brain in the long term.
There are plenty of resources on the internet but to sleep your brain healthy, the Canadian Sleep Society (www.canadiansleepsociety.ca) recommends some basic habits to improve your sleep. Try these simple solutions first.
1. Go to bed only when sleepy and use a relaxing bedtime routine (bath, reading etc)
2. Remove noise, light and other distractions
3. Avoid caffeine, nicotine, and other stimulants
4. Avoid strenuous exercise, large meals or long naps close to bedtime