Glymphatic System and the Upper Cervical Spine

Sleep is widely recognised as essential for cognitive function, metabolic regulation, immune health, and emotional wellbeing. Beyond these general benefits, sleep plays a critical neurophysiological role in metabolic waste clearance within the brain.

We have all been told how important sleep is and how we should get 7-8 hours etc but there is a really important process that occurs only when we are asleep. When we are asleep our brain goes through a process like a biological dishwasher. It washes out toxic proteins that build up in our brain from using it during the day. Our brain consumes around 20% of daily energy and so waste naturally builds up. 


This is so important because a build up of these proteins can wrap around the neurons in the brain and have been linked to neurodegenerative brain diseases like Alzheimer's and neuro-inflammation. 

When we are asleep our brain cells shrink slightly allowing more space for this special fluid called the cerebral spinal fluid to go ahead and wash in and around the cells clearing out the toxic proteins. What’s important to note here is the cerebral spinal fluid (CSF), has to flow around the brain and then back down through the gates of the upper cervical cranial cavity.  It circulates through the cranial vault and spinal canal, driven by arterial pulsation, respiration, and pressure gradients. Efficient glymphatic flow requires unobstructed CSF dynamics throughout the craniospinal axis, including the upper cervical region.


A 2018 study published in Scientific Reports reported a correlation between spinal alignment and glymphatic system function in humans. Using magnetic resonance imaging (MRI), researchers observed that individuals with more optimal spinal alignment demonstrated improved glymphatic transport compared to those with more pronounced spinal curvature. While correlation does not establish causation, these findings suggest that spinal biomechanics/movement may influence CSF dynamics and waste clearance efficiency.


We can further support our glymphathic system by actively trying to achieve good quality sleep hygiene that promotes quality sleep such as;


  • Minimal screen time several hours before bed

  • Not taking devices into our bedroom

  • Reduced caffeine intake and minimal consumption of caffeine after 2pm

  • Exposing our eyes to the first hour of sunlight and last hour before sunset, this helps activate our circadian rhythm and melatonin production 

  • Taking a magnesium salt bath before bedtime, if we struggle to get to sleep

What is also important to note is to make sure we are sleeping on a supportive pillow. The glymphatic system doesn’t work as well if we are sleeping completely flat. We need a slight elevation in our neck for the system to work optimally. 


References 

Iliff, J.J., Wang, M., Liao, Y., Plogg, B.A., Peng, W., Gundersen, G.A., Benveniste, H., Vates, G.E., Deane, R., Goldman, S.A., Nagelhus, E.A. and Nedergaard, M., 2012. A paravascular pathway facilitates CSF flow through the brain parenchyma and the clearance of interstitial solutes, including amyloid β. Science Translational Medicine, 4(147), pp.147ra111.

Xie, L., Kang, H., Xu, Q., Chen, M.J., Liao, Y., Thiyagarajan, M., O’Donnell, J., Christensen, D.J., Nicholson, C., Iliff, J.J., Takano, T., Deane, R. and Nedergaard, M., 2013. Sleep drives metabolite clearance from the adult brain. Science, 342(6156), pp.373–377.

Lee, H., Xie, L., Yu, M., Kang, H., Feng, T., Deane, R., Logan, J., Nedergaard, M. and Benveniste, H., 2015. The effect of body posture on brain glymphatic transport. Journal of Neuroscience, 35(31), pp.11034–11044.

Eide, P.K. and Ringstad, G., 2018. MRI assessment of glymphatic transport in humans. Scientific Reports, 8, Article number: 10219.

Sagirov, A.F., Sergeev, T.V., Shabrov, A.V., Yurov, A.Y., Guseva, N.L. and Agapova, E.A., 2023. Postural influence on intracranial fluid dynamics: an overview. Journal of Physiological Anthropology, 42, p.5.

Benveniste, H., Liu, X., Koundal, S., Sanggaard, S., Lee, H. and Wardlaw, J., 2019. The glymphatic system and waste clearance with brain aging. Gerontology, 65(2), pp.106–119.







Sophie Rumbelow