Researchers in the Whitehall Study followed 7959 British men and women for 30 years, with data on their sleep habits collected at ages 50, 60 and 70. They found that those who slept six hours or less per night had a 30 percent increased risk for dementia, compared with those who slept seven hours or more (Nature Communications, April 20, 2021;12(2289)). Other studies have also shown that short sleep duration is associated with increased risk for dementia (Aging Clin Exp Res, 2019;31:309–320; J Am Med Dir Assoc, 2019;20:1480–1487, e1485).
How Lack of Sleep Could Increase Risk for Dementia
Not getting enough sleep can turn on your immune system to increase production of tissue-damaging chemicals called cytokines (Biological Psychiary, Sep 15, 2008;64(6)). Increased levels of these cytokines are associated with increased risk for inflammation that damages your brain and nerves (Neurobiol Dis, 2012;48:348–355), to increase risk for dementia. This can be seen after just one night of sleep deprivation (Arch Intern Med, 2006;166(16):1756-1762). Many studies show that inflammation causes arteriosclerotic blood vessel damage (Nature, 2019;566:383–387), brain tissue damage in Parkinson’s disease (Ann Neurol, 2021;89:293–303), and increased B-amyloid, a sign of brain damage in Alzheimer’s disease (JAMA Neurol, 2013;70(12):1537–1543).
The authors of the UK study acknowledge that they have not proven that sleep deprivation causes dementia. They have shown only that lack of sleep may be associated with increased risk for dementia.
My Recommendations
Check with your doctor if you have significant sleepiness during the day, chronic snoring, frequent leg cramps or tingling, difficulty breathing during sleep, chronic insomnia, or any other major symptom that interferes with your sleep.
I do not recommend taking sleeping pills. They can help you fall sleep at night, but they tend to lose their effect as you keep on taking them, and they have many serious side effects (Sleep Disord, Dec 9, 2015; 607148).
If you are not getting seven or more hours of sleep each night, try these tips from the American Academy of Sleep Medicine:
• Make sure your bedroom is quiet, dark, relaxing, and at a comfortable temperature. Have a comfortable mattress, pillows and bedding.
• If electronic devices such as a TV, computer or smart phone are keeping you awake, remove them from your bedroom.
• Try to be consistent. Go to bed at the same time each night and get up at the same time each morning, including on the weekends.
• Avoid large meals, caffeine, and alcohol in the evening. Finish dinner at least three hours before your bedtime and do not snack.
• Get plenty of exercise. Being physically active during the day can help you fall asleep more easily at night.
