If there is one thing we want to do,, it is to maintain our memory, and now we may have found the key to doing that: running.

Researchers have always known that exercise is critical to our physical and mental health. Muscles and muscle development, in many yet unknown ways, can strengthen neural connections and affect hormones and neurotransmitters. However, one thing that they have always suspected, and now we have research evidence to prove, is that running can increase the portion of our brain, the hippocampus, which is responsible for memory formation and retrieval.

But there’s something new that’s not simply related to muscles but to the nerve fibers in our body and the delicate wrapping around each one: the myelin sheath, those onion-like cells that protect our nerves. The cells are made up of fatty material (lipids) that are more than stand-bys waiting to do their job.

Although it has not been definitively demonstrated, new research implies that myelin fats might serve as energy stores without glucose. One MRI study aimed to determine whether marathon running altered myelin content. The research shows that runners experience a robust myelin reduction all over their bodies when a marathon is finished. But it doesn’t end there with a depletion of those wonderful protectors.

Specifically, myelin levels have partially recovered within two weeks following a marathon. The body is pulling reserves into action and then rebuilding them, similar to us making withdrawals from banks and then making new deposits.

The research effort may have therapeutic ramifications. People who have experienced myelin loss due to age or neurodegenerative diseases may benefit from discovering how runners’ myelin repairs so quickly. This knowledge could develop viable remedies for conditions such as multiple sclerosis.

Aside from the myelin, what else might be affected by running? We know that walking is good for us, whether slow or fast. However, that research primarily deals with muscles, bones, and mood and what walking can provide. But what about the brain?

Researchers discovered that 75 percent of the 10,125 healthy participants (average age: 52) who had magnetic resonance imaging (MRI) examinations and exercised moderately or vigorously four days a week showed some dramatic changes. The study’s preponderance of male participants is an issue that requires attention in research but was seemingly under-discussed in this case.

The brain scans of these volunteers showed that important regions, including the hippocampus (responsible for memory formation) and the frontal, parietal, and occipital lobes (responsible for judgment and also linked to Alzheimer’s), were larger compared to people who exercise less.

Consider only the hippocampus and what research has discovered regarding exercise and that portion of the brain. The results of a 12-week moderate-intensity exercise intervention to improve cardiorespiratory fitness led to increased hippocampus volume in people in their early to middle-aged years.

One aim of neuroscience is to preserve portions of the brain responsible for memory and learning, such as the hippocampus, and research has shown the effect of walking. In a 12-week study of patients with MS using a treadmill, when compared to the control condition, where hippocampus volume was lost, the intervention condition showed preservation of hippocampus volume. Although this research did not attempt to match walking with repairing or restoring damaged Schwann cells’ myelin, we could carefully assume that there might be a connection.

However, as in everything else in research, a meta-analysis of brain volume and exercise found contradictory findings. The purpose of the meta-analysis and comprehensive review was to determine whether exercise in older persons participating in randomized controlled trials (RCTs) altered their brain volume and, if so, how. The results showed no difference in brain volume between the control group and the older people who participated in the exercise intervention, contradicting the hypothesis.

The question for all of us remains: should we exercise or not? This is the wrong question because we know that all exercise is good for us in too many ways to mention. Specifically, running or walking may not do what some research purports it has shown. However, this does not show that we should avoid or engage in running or walking during our lifetimes. Obviously, either one is good exercise, and you will receive benefits from them, but brain volume is still to be determined.

There may be too many factors involved in the decrease in brain volume, and brain volume may not be the be-all and end-all we assume. In the past, I've read of one case where a young girl had almost no brain volume, and yet she functioned perfectly fine. The portion of her brain that was present was the outer aspects. Unfortunately, at the time of the study of her impairments, there was no MRI, and X-ray technology was quite limited.

And she wasn't the only case because there were others. A young boy, math genius in Ireland was also missing significant portions of his brain. A man in France was missing 90% of his brain and functioned normally with an IQ in that range.

There is no last word other than it's a good idea to exercise in whatever way you find most comfortable, convenient, or that matches your ability level. Choosing one type may provide whatever changes you seek regarding physicality, but we can make no definitive statements regarding brain volume or its effect on memory.