The lead author of the new research is Jennifer Heisz, an assistant professor in the Department of Kinesiology at McMaster University.
Heisz and her colleagues show that 20-minute daily sessions of interval training for 6 weeks dramatically improves performance in a so-called high-interference memory task.
The interference memory theory refers to the way in which information that we already know and have memorized may interfere with our ability to learn new material.
Good interference memory means that old knowledge works seamlessly with new information, enabling us, for example, to distinguish a new car from our old one, even if they are the same brand and model.
Intense exercise boosts interference memory
Heisz and her team recruited 95 young adult participants for their study. The participants engaged in one of the following three scenarios for a duration of 6 weeks: physical training plus cognitive training, physical training only, or no training at all.
The physical exercise sessions consisted of 20 daily minutes of interval training.
Participants were also asked to take part in a high-interference memory task, wherein they tried to recognize pairs of matching faces from an array of very similar images.
The team also measured their levels of a protein called brain-derived neurotrophic factor (BDNF), as well as insulin-like growth factor-1, both before and after the interventions. BDNF promotes the survival, growth, and maintenance of neurons.
The researchers found that the group who had engaged in intense physical activity performed much better at the high-interference memory task and had higher levels of BDNF compared with the control group.
Additionally, the combined training group had similar performance levels with the exercise-only group.
Findings particularly important for seniors
“These findings are especially important, as memory benefits were found from a relatively short intervention,” the authors emphasize.
“Improvements in this type of memory from exercise,” explains Heisz, “might help to explain the previously established link between aerobic exercise and better academic performance.”
The study also hints at a potential mechanism that may explain how exercise and brain training may work together to improve cognition.
“Taken together, the results suggest that the potential for synergistic effects of combining exercise and cognitive training may depend on individual differences in the availability of neurotrophic factors induced by exercise,” the authors conclude.
Heisz says that the findings may bring good news for older adults in particular, saying, “At the other end of our lifespan, as we reach our senior years, we might expect to see even greater benefits in individuals with memory impairment brought on by conditions such as dementia.”
“One hypothesis is that we will see greater benefits for older adults given that this type of memory declines with age,” explains Heisz, whose team have already started to investigate this hypothesis.
“However,” she notes, “the availability of neurotrophic factors also declines with age and this may mean that we do not get the synergistic effects.”