Adding to a growing body of evidence highlighting the importance of sleep, researchers recently discovered that poor sleep quality is associated with a loss of brain volume among older adults.
It is likely that at some point, most of us have experienced a sleepless night. Past research shows that when sleep is cut short, the body is unable to complete all the steps necessary to repair muscles, consolidate memory, and release hormones that regulate growth and appetite. But according to a new study published in the journal Neurology, sleep difficulties may also be linked to faster brain volume decline.
The relationships between sleep and both mental and physical health are well documented, and recent research has suggested that shortened sleep speeds up the aging of the brain in older people. For instance, a study published last month in the journal Sleep found that for every hour of reduced sleep in the participants — who were all over the age of 55 — there was an incremental expansion of the brain ventricles and a decline in global cognitive performance.
According to the National Sleep Foundation, sleeping too little can inhibit productivity and affect our ability to remember and consolidate information.
However, lack of sleep is also linked to:
- Increase in body mass index (BMI)
- Increased risk of diabetes and heart problems
- Increased risk for psychiatric conditions, such as depression and substance abuse
- Decreased attention span, ability to react to signals or remember new information.
To further investigate the link between sleep deficits and brain volume, the researchers from this latest study analyzed 147 participants, who were between the ages of 20-84 years old.
‘Not yet known if poor sleep is a cause or consequences of brain changes’
To assess sleep quality, researchers performed two MRI brain scans — separated by a period of about 3.5 years — on the study participants, all of whom also completed sleep habit questionnaires.
The assessment evaluated how long the participants slept, how long it took to fall asleep at night, and whether they use any sleeping medication, among other factors. In total, 35 percent of the participants fell under the “poor sleep quality” category, with an average score of 8.5 points out of 21.
Results showed that those who had sleep difficulties during the study period also had a more rapid, widespread decline in brain volume across multiple regions, such as the frontal, temporal and parietal areas, with effects more evident in those over the age of 60.
Because of the study design, a causal relationship could not be determined, explains study author Claire E. Sexton, from the University of Oxford in the UK. “It is not yet known whether poor sleep quality is a cause or consequence of changes in brain structure,” she says.
“There are effective treatments for sleep problems, so future research needs to test whether improving people’s quality of sleep could slow the rate of brain volume loss,” adds Dr. Sexton. “If that is the case, improving people’s sleep habits could be an important way to improve brain health.”
Though sometimes improving sleep habits is easier said than done, the National Sleep Foundation provide a number of sleep tips, including:
- Establishing consistent sleep/wake schedules
- Creating a regular, relaxing bedtime routine
- Establishing a dark, quiet and comfortable sleep environment
- Sleeping on a comfortable mattress and pillows
- Using the bedroom only for sleep and sex, not for watching TV or using a computer
- Exercising regularly
- Avoiding caffeine/alcohol close to bedtime.
In the future, Dr. Sexton says she and her team “would like to investigate whether improving sleep (for example, through cognitive behavioral therapy, physical exercise or pharmacological treatments) can help slow decline in brain volumes.”
Meanwhile, in a breakthrough study published in June, researchers for the first time discovered the mechanism by which sleep strengthens new memories after learning. According to the analysis, sleep promotes new connections between neurons involved in the processes of learning and memory formation; conversely, sleep deprivation obstructs the development of new synaptic connections, resulting in poorer cognitive functioning.