What causes age related memory loss?

As we get older our memory usually gets worse. Almost everyone knows someone who gets a little more forgetful with age. Some later than others but it seems inevitable. What causes this and is there nothing we can do to prevent or slow down this process?

Our memory is not bound to a single brain structure. Different parts of our brain function as different parts of what we call our memory. For example we have a special memory for movement patterns that we perform without thinking such as walking or riding a bike. These are stored in and retrieved from the cerebellum, the smaller brain behind our large brain (cerebrum). Furthermore both the frontal and temporal lobes play a large part in our memory. Another important structure in forming memories is the hippocampus. The hippocampus, among other things, transfers memories from our short term memory to our long term memory. When the hippocampus gets damaged this process gets interrupted and making new memories might be impossible.

As we get older several changes take place in our brains. One of these is arteriosclerosis. Our brains use about 20% of the total amount of oxygen that our body uses at rest. Consider that our brains take up only 2% of our total mass and you can see that oxygen and therefore blood needs are quite high. When the quality of our blood vessels decreases blood supply to our brain is compromised. To function optimally, the brain needs an unobstructed blood supply. Arteriosclerosis prevents this and is one of the causes of age related memory loss.

We do not know everything about how the brain functions and how it changes during aging. Aside from that, hereditary factors can play a large role in the aging brain. There is good news however. Arteriosclerosis can be prevented or even reversed by adopting a healthy lifestyle. Aerobic exercise in particular can reverse arteriosclerosis and therefore improve blood flow to the brain.

Is age related memory loss inevitable?

Another reason for age related memory loss is a decrease in mass in the hippocampus. As said before, the hippocampus is essential in forming long term memories. A decrease in size compromises memory.

In addition, both strength training and aerobic exercise can increase the size of the hippocampus, or at least prevent it from shrinking. An important factor in this is training intensity. A higher training intensity in both strength training and aerobic exercise requires more concentration and therefore can be seen as exercise for the brain.

An different way of training the brain is performing more complex exercises such as maintaining balance while performing memory tasks or solving math problems in your head. Other possibilities are learning a new skill that involves complex movement patterns such as juggling or playing a new instrument.

Finally a healthy lifestyle is essential in maintaining a well functioning brain. As said before, arteriosclerosis is an important factor in age related memory loss. The process of arteriosclerosis can be accelerated by physical inactivity, unhealthy nutrition, too much stress, smoking and drinking alcohol. Improving your lifestyle in any or all these fields will be of great benefit to your brain.

In short, although it is not avoidable for everyone, much can be done to prevent or slow down age related memory loss and improve health at the same time.

See also:

-Fitness and depression

References:

– Bear, M.F., Connors, B.W., Paradiso, M. A. Memory Systems. In: Neuroscience exploring the brain 2nd edition. USA Lippincott Williams & Wilkins.

-Frodl, T., Strehl, K., Carballedo, A., Tozzi, L. Doyle, M., Amico, F., Gormley, J., Lavell, G., O’Keane, V. Aerobic exercise increases hippocampal subfield volumes in younger adults and prevents volume decline in the elderly. Brain Imaging and Behavior 2019.

-Netz, Y. Is There a Preferred Mode of Exercise for Cognition Enhancement in Older Age?—A Narrative Review. Frontiers in Medicine 2019, 6, 57.

-Roque, F.R. Hernanz, R., Salaices, M., Briones, A.M. Exercise Training and Cardiometabolic Diseases: Focus on the Vascular System. Current Hypertension Reports 2013, 15, 3, 204-2015.