Physical activity helps reduce memory decline

This study by psychologists at the University of Illinois at Pittsburg is not directly related to Alzheimers and dementia but it does tell us about how to keep our spatial memory functioning even at an advanced age.

The hippocampus is a curved structure deep inside the medial temporal lobe of the brain, is essential to memory formation. And for this part of the brain, size does matter. The bigger your hippocampus is, the better is your ability to store new experiences and the better is your spatial memory skills. A damage hippocampus however, prevents an individual to form new memories, as in the well-known case of Henry Gustav Molaison (also known as HM or Henry Right Now) who suffered from retrograde amnesia.

Certain activities make the size of the hippocampus bigger in some people and smaller in others.

For example, a study of London taxi drivers found that the posterior portion of the hippocampus was larger in experienced taxi drivers than in other subjects. And a study of German medical students found that the same region of the hippocampus increased in size as they studied for their final exams.

The size of the hippocampus, however, decreases with age, and with it certain brain functioning. The deterioration of spatial and relational memory in the elderly is one of the major causes of loss of independence and disorientation.

The shrinkage of the hippocampus, however, varies from one individual to another and the researchers found that one way of keeping the hippocampus- and thus memory skills fit is through physical exercise.

This has been observed before in laboratory studies using rodents. The University of Illinois researchers looked at 165 adults aged 59 to 81 years old. 65% of the participants were females. The researchers measured the cardiorespiratory fitness of the participants and conducted a volumetric analysis of the subjects’ left and right hippocampi using magnetic resonance imaging (MRI). The participants’ spatial reasoning was also tested.

The study results revealed that there is a significant link between an individual’s physical fitness and his or her performance in spatial memory tests as well as the size of his or her hippocampus. The size of the hippocampus in physically fit adults accounts for about 40% of their advantage in spatial memory.

According to lead researcher Kirk Erickson

“This is really a clinically significant finding because it supports the notion that your lifestyle choices and behaviors may influence brain shrinkage in old age. Basically, if you stay fit, you retain key regions of your brain involved in learning and memory.”

We all the benefits of exercise to our cardiovascular health. This study gives me another reason to leave my desk and go for a run in the early spring rain.

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