Exercise not only gets the blood pumping, but new research finds that even a brief burst of exercise can bolster a person’s memory powers.
What this demonstrates is that exercise primes the brain for learning – and suggests that school students would benefit from more frequent, if shorter, periods of exercise in schools.
It also has implications for middle aged and older people seeking to put up a defence against memory loss.
It’s also a significant addition to the body of evidence linking brain health to physical activity.
Previous research has found that structured exercise training can significantly improve brain function in stroke survivors; aerobic exercise increases brain volume, notably in the hippocampus; sustained physical activity leads to long-term cognitive gains; and exercise was associated with improved brain function in a group of adults diagnosed with mild cognitive impairment.
Now neuroscientists, working with mice, have discovered a short burst of exercise directly boosts the function of a gene that increases connections between neurons in the hippocampus, the region of the brain associated with learning and memory.
“Previous studies of exercise almost all focus on sustained exercise,” said co-senior author Dr Gary Westbrook, senior scientist at the Oregon Health and Science University (OHSU) Vollum Institute and Dixon Professor of Neurology in the OHSU School of Medicine.
“As neuroscientists, it’s not that we don’t care about the benefits on the heart and muscles but we wanted to know the brain-specific benefit of exercise.”
The scientists designed a study in mice that specifically measured the brain’s response to single bouts of exercise in otherwise sedentary mice that were placed for short periods on running wheels. The normally lazy mice ran a few kilometres in two hours.
The study found that short-term bursts of exercise – the human equivalent of a weekly game of pickup basketball or 4000 steps – promoted an increase in synapses in the hippocampus.
(A synapse is a junction between two nerve cells, consisting of a tiny gap across which impulses pass by diffusion of a neurotransmitter.)
Scientists made the key discovery by analysing genes that were increased in single neurons activated during exercise.
One particular gene stood out: Mtss1L. This gene had been largely ignored in prior studies in the brain – and is now a source of excitement in the research community.
The Mtss1L gene encodes a protein that causes bending of the cell membrane. Researchers discovered that when this gene is activated by short bursts of exercise, it promotes small growths on neurons known as dendritic spines – the site at which synapses form.
Dendritic spines contain neurotransmitter receptors, organelles and signalling systems essential for synaptic function and plasticity.
Numerous brain disorders are associated with abnormal dendritic spines. Spine formation, plasticity, and maintenance depend on synaptic activity and can be modulated by sensory experience.
The researchers note that human studies give support for the idea that exercise within four hours of a learning task improved memory performance.
In the next stage of research, scientists plan to pair acute bouts of exercise with learning tasks to better understand the impact on learning and memory.