The Incredible Shrinking Brain

You know what they say about a good night’s rest….it shrinks the brain. Wait, what? How can that possibly be a good thing?

First let me explain the “taking out the garbage” system we have in the body called the LYMPHATIC SYSTEM. The lymphatic system is a network of tissues and organs that help the body rid itself of toxins, waste, and otherwise unwanted materials. The function of the lymphatic system is primarily to transport lymph (which is a fluid containing infection-fighting white blood cells) throughout the body. It does so by traveling through lymphatic vessels, similar to the circulatory system’s veins and capillaries. How it works is, a threat enters our body and makes its way into the lymphatic fluid. Eventually, that threat (virus, bacteria, microbes, toxins) travels in the lymph fluid to the lymph nodes where the white blood cells are housed and waiting to attack the invader. Essentially, “taking out the garbage” and eliminating it as waste.

The brain, however, does not get the benefit of the lymphatic system. Instead, it has cerebrospinal fluid (CSF).  The brain’s waste removal system is called the GLYMPHATIC SYSTEM. It is called the glymphatic system because of its dependence on glial cells found only in the central and peripheral nervous systems. The glymphatic system uses the cells mitochondria to remove cellular waste from the brain. It’s the CSF that is responsible for draining the toxins from the brain.

Scientists have discovered that the space between the brain cells increase during sleep, allowing the brain to complete the task of flushing toxins that build up during waking hours. “Sleep changes the cellular structure of the brain,” said Maiken Nedergaard, M.D., D.M.Sc, co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center in New York. “The space between the brain cells changed greatly between conscious and unconscious states.” Sleep is the period in which the brain cleanses itself of toxic molecules, and that doesn’t happen while we are awake. Once we are asleep, though, the glymphatic system opens up, letting the CSF flow rapidly through the brain. In order to make room for this flood of fluid, the brain must make room. It shrinks.

But wait! There’s more. Not only does your brain dump the toxins during sleep. That extra room in there serves another purpose: learning, forming new memories, keeping the important memories, pruning the unnecessary.

This 20% brain shrinkage during sleep helps your brain grow stronger and make sense of information received during the waking hours.

When we are awake, we are servants of the here and now, always attending to some stimuli and processing something. During sleep, we are not preoccupied by the external world and the brain can assess all our synapses (Synapse is the junction between two nerve cells, the junction where nerve cells pass a signal, or electrical charge, to another neuron) and reorganize them in an intelligent way. Kind of like a file system.

The Greek philosopher Aristotle suggested that sleep was restorative, a time to replace and rebuild all that was burned up during the day. Scientists are showing that he wasn’t far off the mark. Sleep plays a large role in the growth of synapses, which act as the highway ferrying information among neurons. Synapses are constantly strengthening, or widening, during the day to accommodate that heavy flow of traffic as the brain takes in new experiences and information. But that strengthening can’t go on indefinitely or the synapses burnout – like system overload. It is critical to have that pruning back at night so that huge amount of information encoded temporarily during the day doesn’t overwhelm the brain. This nightly pruning ensures that the important information is retained.

Brain shrinkage is important to overall health in helping us flush toxins from the brain and helping us file away, in a logical manner, the important information we need to retain.

Want to improve your brain health? Let your brain shrink. Get quality sleep every night.

Here are 6 easy steps to make sure you get your nightly zzzzz’s:

Establish a schedule. Go to sleep and wake up at the same time every day, even on weekends.

Practice a nightly ritual. This will send the signal to your brain and body that it is time to wind down and prepare for sleep.

Exercise daily (but make it early). Vigorous exercise is known to reduce the time is takes to fall asleep, just not when you exercise right before bed.

Clean up your sleeping environment. Your room should have minimal distractions. No TV, no work stations, no devices. It should be cool, between 60-67 degrees is best. It should be free from any noise and light.

Avoid stimulants/chemicals before bed. Caffeine, alcohol, nicotine are no-nos.

Avoid too much fluid intake. You want to make sure you are staying hydrated throughout the day. Just be sure to get those fluids in before bedtime otherwise your sleep will be disrupted for constant trips to the bathroom.

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