On your back, face down, on the side—when you’re napping or going to bed for the night, what position do you tend to sleep in?
A pre-clinical study suggests how we sleep, especially if it’s in a lateral position (also known as side-sleeping), can help flush out waste in the brain as we sleep. This waste removal is essential in carrying out brain functions like problem-solving, reasoning and attention to detail—along with keeping your brain healthy.
Researchers from Australia specifically wanted to know how the glymphatic system, a network of vessels that helps remove waste in the brain, could prevent neurodegenerative diseases like amyotrophic lateral sclerosis (ALS), the most common motor neuron disease that affects nerve cells in the brain and spinal cord. People diagnosed with ALS can gradually lose their ability to speak, eat, move and breathe.
The glymphatic system and its waste removal role in the brain
If you don’t get enough sleep or don’t sleep at all, the brain cells known as neurons take up large amounts of energy. When this happens, neurons expel debris that can float around the brain and prevent it from functioning normally. That debris – made up of leftover proteins – can later form clumps that are toxic to the brain.
An accumulation of these types of protein (including amyloid-beta) has been linked to neurodegenerative diseases, including Alzheimer’s, Parkinson’s, Huntington’s and dementia.
Natalie Dautovich, PhD, an environmental fellow at the National Sleep Foundation and an assistant professor in the Psychology Department at Virginia Commonwealth University, told Seasons the glymphatic system is the brain’s “housekeeper” and is key in removing waste in the brain. The system is also most active while we sleep. However, she said when we’re sleep-deprived, the system is largely dormant, allowing neural waste to accumulate.
“The glymphatic system uses cerebral spinal fluid to flush neural waste products from the brain,” she said. “Recent, cutting-edge research suggests that sleep is critical for creating the optimum environment for this ‘brainwashing’ to occur.”
Furthermore, research conducted in rodents found glymphatic clearance is most efficient in the lateral (or side-sleeping) position, compared to either supine (on the back) or prone (front-lying) positions, according to David Wright, PhD, associate professor in the Department of Neuroscience at Monash University.
Yet, the reasons for why certain positions are more effective in helping the glymphatic system clear brain waste are not fully understood at this time, but could possibly be due to “the effects of gravity, compression and the stretching of tissue,” Wright added.
How to improve the glymphatic system function (in addition to sleep)
Even though experts are still learning about the role of the glymphatic system in neural functioning, there are small lifestyle changes that can improve brain waste clearance and minimize the risk of developing neurodegenerative diseases. According to Wright, some of those changes include:
- Moderate consumption of alcohol – In mouse studies, exposure to moderate amounts of alcohol was shown to boost lymphatic function, while high doses of alcohol had the opposite effect.
- Exercise – Regular exercise has also been found to improve memory and cognition in neurodegenerative diseases and can help glymphatic clearance.
- Consuming certain vitamins – Research shows that omega-3 or fish oil pills can help promote protein clearance from the brain and have a positive effect on glymphatic function.
While these are worth considering, Wright said more research is needed “to focus on therapies directly targeting the glymphatic system to help those already suffering from these debilitating diseases.”
What else you need to know about the study
To answer how the glymphatic system plays a role in preventing ALS, Wright and his colleagues turned to mice.
Some mice were genetically modified to express the human protein connected to ALS, a protein called TDP-43. Some mice were fed food containing an antibiotic called doxycycline, which allowed the researchers to turn the TDP-43 expression off, and in the end permitted the mice to age normally. However, when the genetically modified mice switched to normal food, the TDP-43 expression was turned on and toxic proteins began to accumulate.
They found that over time the genetically modified mice displayed classical signs of ALS, including gradual muscle impairments and brain atrophy, a loss of neurons.
“What the study showed is that the ALS brain in the mice actually had reduced clearance of the cerebrospinal fluid (CSF) compared to the normal brain,” Santosh Kesari, MD, PhD, a neurologist at Providence Saint John’s Health Center in Santa Monica, California (who was not a part of the study), told Seasons.
Reduced clearance of CSF in the brain is believed to contribute to the development of many diseases, including neurodegenerative conditions such as Alzheimer’s disease and multiple sclerosis.
In addition, by using magnetic resonance imaging (MRI), the researchers found the genetically modified mice had a harder time clearing waste from the brain compared to the control mice.
“Our study provides the first evidence that the glymphatic system might be a potential therapeutic target in the treatment of ALS,” Wright wrote in The Conversation. “Sleep position is also thought to affect glymphatic clearance.”
“Symptom onset in ALS is often insidious, and diagnosis remains challenging. As such, a definitive diagnosis is often delayed and misdiagnosis is common,” he added. “The imaging methods we have employed may assist clinicians in making an earlier diagnosis, bringing forward treatment and enabling earlier enrollment in clinical trials.”
How to encourage comfortable and high-quality sleep
The National Sleep Foundation recommends these practices for better sleep:
- Spend time in bright light during the day.
- Exercise regularly.
- Eat meals at consistent times daily
- Avoid alcohol, caffeine, nicotine and heavy meals before bedtime.
- Stick to a sleep routine or schedule.
- Avoid electronics and other devices before bedtime.
Finding the right pillow can also make sleep more comfortable or can encourage side sleeping. A proper pillow helps keep the neck aligned with the spine while sleeping. It can also properly support the head to keep it in alignment and prevent it from tipping toward the mattress.