Sleep is divided in two stages as the deep non-rapid eye movement sleep (NREM) and lighter rapid eye movement (REM) sleep when dreams occur. Evidence suggest that, every night during the deep NREM phase of sleep, the cerebrospinal fluid clears the brain of unwanted protein aggregates that are toxic to the brain [1,2]. Increasing studies show that poor sleep or occupational chronic sleep deprivation in mid-life poses a significant risk for cognitive decline later on [3,4].
Maintain a regular sleep schedule and try improve sleep by exercising, being exposed to bright light in the morning and having regular eating patterns during the day, including not eating late in the evening. If you think you may have or be at risk of having sleep apnea, get tested and make sure you follow appropriate advice to prevent this if diagnosed. There is some evidence that taking medications to aid sleeping may increase dementia risk . Instead it is recommended that one first tries to improve sleeping using natural approaches such as preventing noise disturbance, limiting caffeine intake, using blackout curtains and avoiding the use of electronic devices in the late evening.
 Lucey BP, McCullough A, Landsness EC, Toedebusch CD, McLeland JS, Zaza AM, et al. Reduced non–rapid eye movement sleep is associated with tau pathology in early Alzheimer’s disease. Science Translational Medicine 2019;11.
For further advice on maintaining brain fitness, we recommend the following reading: