Can an Easy 10-Minute Exercise Deliver a Real Memory Boost?

A brief spin on an exercise bike improved recent memories in this research.

Posted Sep 30, 2018

A ten-minute exercise that boosts memory and the brain activity that supports it might be dismissed as just another click-bait claim but it’s worth a closer look. Just 10 minutes of moderate, non-stressful effort on a bicycle ergometer, similar to an exercise bike, led to better performance on a test of recent memory. The test required 36 young adults to look at a series of images of common objects like flowers or vegetables one after the other and recognize which of them were the same or similar to items shown previously. It is a test of episodic memory, similar to recognizing someone at a party you met on a previous occasion. 

Forrest Gump spent three years running across the country in the 1994 movie with the same name, but 10 minutes at a time is more practical for many of us. That brief exercise also led to increased activity in the hippocampus, the brain region most associated with recent memory, and to more connectivity between the dentate gyrus/CA3 regions of the hippocampus and specific regions of cerebral cortex associated with memory storage, according to Michael Yassa, PhD of the University of California at Irvine (UCI) and his colleagues at the University of Tsukuba in Japan, writing in the Proceedings of the National Academy of Sciences. Damage to the hippocampus has led to an inability to form new memories, even if long-term memories from childhood remain.

Neural activity was measured by brain scans using functional magnetic resonance imagery or fMRI. Connectivity was measured by the density of nerve fiber connections lined up alongside each other, which allows them to send more signals between groups of nerve cells in a short period of time. You could compare it to drinking more liquid in a minute by using a bundle of big straws. When individuals were compared, connectivity was correlated with increased performance in the memory test.

Since past memories have been so much in the news lately, it is important to note that saving memories of events or episodes, called episodic memory, is most closely associated with the hippocampus. However, emotionally-charged memories of threatening or traumatic events appear to be stored by another nearby structure, the amygdala. A very rough comparison might be to different flash memory drives devoted to different types of information.  

“The hippocampus is critical for the creation of new memories; it’s one of the first regions of the brain to deteriorate as we get older – and much more severely in Alzheimer’s disease,” said Yassa, according to UCI News on September 24. “... Improving the function of the hippocampus holds much promise for improving memory in everyday settings.”

The authors’ hypothesis was that the activity and connectivity of the hippocampus are essential for storing episodic memories. A skeptic might point out that this study involved only 16 to 20 participants in each condition or test, that memory effects were statistically significant but limited, and that arousal following the exercise could have had nonspecific effects on attention and memory. But the results are certainly encouraging to those who need additional reasons to get off the couch.

References

Suwabe, K., Yassa, M.A., Soya, H. and others (2018). Rapid stimulation of human dentate gyrus function with acute mild exercise. PNAS published ahead of print September 24, 2018 https://doi.org/10.1073/pnas.1805668115