That fuzzy, inability-to-focus feeling after a bad night’s sleep can have more lasting and detrimental results for the elderly, especially when it becomes routine.

According to a study published in the Journal of the American Medical Society (JAMA) Network, poor sleep habits in older people can be directly connected with lower cognitive function than their well-rested peers, and faster cognitive decline.

The researchers mined data from studies in England and China, focusing on the reported sleep patterns of approximately 30,000 people.

The information did not surprise Patty O’Brian, a dementia specialist with the Hartford HealthCare Center for Healthy Aging who gives talks on sleep’s impact on healthy brains.

Besides giving neurons in the brain a chance to repair and restore themselves to perform normal cellular activity the following day, sleep also clears waste from the brain to support learning and memory.

“This happens through a newly discovered drainage system called the glymphatic system” O’Brian said. “Its job is to clear out and recycle all the brain’s toxins. Cerebral spinal fluid increases while we sleep, washing away harmful waste proteins that build through the day.”

For this reason, she said researchers at Stony Brook University determined that good sleep, especially sleeping on one’s side, helps reduce the chances of developing Alzheimer’s disease, Parkinson’s disease and other neurological conditions.

The JAMA study noted that those most at risk for memory problems reported insufficient sleep, or fewer than four hours a night, or excessive sleep, more than 10 hours a night.

“Sleep is necessary to consolidate a memory, or make it stick so it can be recalled in the future,” O’Brian said, explaining that consolidation refers to stabilizing a memory in the brain.

The information, according to the JAMA researchers, adds to existing evidence supporting healthy sleep patterns in an age group that will make up one fifth of the world’s population by 2050.

O’Brian offered the following tips for getting a good night’s sleep:

  • Keep stable sleep and wake times each day.
  • Avoid electronics for up to an hour before you want to fall asleep. Do not watch TV or use a laptop in bed.
  • Get regular exercise, but not too close to bedtime.
  • Create a pleasant sleeping environment that is dark, cool and comfortable.
  • Avoid caffeine, alcohol and nicotine before going to sleep.
  • Use a sound machine to block out disruptive noise.
  • Make a to-do list before you go to bed to prevent lying awake worrying about things.
  • If you wake up and cannot fall back to sleep, try reading or doing something that is not overly stimulating.

“We suggest people keep their phones and other gadgets out of the bedroom,” O’Brian said. “The blue light emitted by the screens restrains the production of melatonin, the hormone that controls your sleep-wake cycle. Plus, technology can trick the brain into thinking it needs to stay awake.”