As we age, our memories usually become worse and therefore less reliable – that is inevitable. Or is it? Scientists are trying to find out how to curtail the deterioration of cognitive ability, and a recent study has shown that simply a few minutes of light exercise can help.

Cognition is the ability to learn, solve problems, remember, and appropriately use stored information. And now, finding out and understanding the ways in which we could possibly reduce slowing of this is more important than ever before, as the numbers with brain disorders and mental problems increase every day, along with the aging population as mentioned above.

The hippocampus, which sits in the temporal lobe of the brain, is of great interest to researchers trying to solve this issue, as it is vital for learning and memory. The hippocampus is quite sensitive to stress, and is one of the first regions of the brain to suffer as we grow older. This is even clearer to observe in people with Alzheimer’s disease (a degenerative brain disorder and the most common cause of dementia). Studies had already suggested in the past that exercise could improve some areas of cognitive ability (including memory) – adults who are more physically active tend to have an increased hippocampal volume, which then naturally leads to improvements in memory performance. Scientists have asked if physical activity stimulates the growth of new brain cells in the hippocampus, hence leading to this increased volume (through a process called neurogenesis). This would take some time, however, and therefore any benefits that may come about would take a while to become noticeable.

Recently, a team from the University of California, Irvine and the University of Tsukuba in Japan investigated whether exercise can enhance memory over a shorter period of time – say, in minutes, instead of days or weeks.  Yes, the theory about brain cell growth is possible, but there may also be another, quicker mechanism that works alongside neurogenesis. And so, 36 young participants carried out 10 minutes of light exercise, after which the team used MRI to measure any changes in brain activity. This showed improved connectivity between the dentate gyrus (a part of the hippocampus that plays a role in laying down new episodic memories) and cortical areas which are involved in detailed memory processing. Furthermore, when the participants were given a memory recall test, this increased connectivity had a correlation with an improvement in memory performance.

The team is keen to continue investigating, but with more long-term studies with older adults, who have a greater risk of cognitive decline. The co-leader of the project said ‘improving the function of the hippocampus holds much promise for improving memory in everyday settings’, and this is very true; the discovery that some light exercise can have an impact on the parts of the brain dealing with memory is a big step, but it is also only the first step. Now, we need to gain a clearer understanding of the ideal level of activity required, in order to make a lasting difference.

Photo Credits due to: Malhar Mukne

Malhar Mukne