We've all seen Elon Musk's grand plans to send people to Mars. In fact, with his company SpaceX building and testing its newest and largest rocket now, we should soon see a manned flight around the moon. So what are the physical implications of all of this commercial space travel on the body? New research suggests it may get interesting. Let me explain.
White Matter and Gray Matter: Why Volume Matters
The brain consists of two main tissues—the gray matter and the white matter. When you look at a model of the full brain, you are looking at the gray matter, which does actually have a grayish color. It is the outer cortex of the brain and what you typically envision when you think of the brain. The white matter is deeper brain tissue that lives beneath the gray matter and makes up the central core of the brain. The white matter contains the fat-covered axons of nerve cells, while the gray matter contains the cells themselves, specifically the terminals for the axons and the dendrites.
So the job of the white matter is to serve as the brain’s highway system, transporting impulses between nerve cells in the gray matter. Healthier white matter, therefore, means faster processing of information. The gray matter contains many regions involved in many different functions, such as cognitive function, emotions, decision making, sensory processes (e.g., speaking, sight, etc.), memories, muscle communications, and so on. It’s the density of the cells in these tissues that determine the volume, and the more volume we have in the gray matter and white matter as we age, the stronger the brain.
How Lack of Gravity Affects Brain Volume
The purpose of the new study was to investigate how microgravity, or the near absence of gravity, affects brain volume. Researchers analyzed the gray matter and white matter as well as cerebrospinal fluid in the brains of 10 astronauts who spent an average of 189 days in space. Gray matter volumes were found to be reduced at nine days postflight; however, these had mostly recovered seven months later. White matter volumes were found to still be reduced at the seven-month post-flight examinations. CSF (the fluid that surrounds the brain) volume was found to be increased in certain areas at nine days post flight, with some increases, such as in the subarachnoid space still present at seven months, suggesting the spaces created by reductions in white matter were slowly being filled in by the increased cerebrospinal fluid.
Researchers translated these findings to the risk of potential clinical conditions after long bouts in space, including visual disturbances, which the astronauts experienced, possibly due to the increased pressure caused by the extra volume of CSF. The goal is to eventually determine ways to minimize these effects on the brain during space travel, especially in those participating in lengthy missions.
What Else Can Affect Brain Health?
Very few of us will ever have the opportunity to spend any time in space, so most of us don’t have to be too concerned about the effect of microgravity on our brain. However, there are many other issues, even those that could affect us daily, that we may want to be aware of when it comes to brain health. Let’s review a few:
- For those with fibromyalgia who have atrophy (shrinking) of the gray matter in the brain, regulating sleep has been shown to not only slow but even reverse this atrophy.
- The environment in our gut has been linked to emotion processing in our brain, with specific healthy gut bacteria being associated with thicker gray matter in the brain.
- Exercise, even just 10 minutes worth, has been shown to give us a nice brain boost.
- Curcumin or turmeric root may regenerate nerve cells in the brain, making them beneficial to brain health.
The upshot? Could these and other changes that happen to the body in outer space impact the health of all of those SpaceX Mars colonists? Or will we just evolve into a subspecies in outer space, our bodies adapting to our new environment? Will these colonists whose bodies have so dramatically changed ever be able to come back to mother earth? Only time will tell, but if Musk has his way, we should know all of this in the next 10–15 years!