To what degree is increased blood flow to the brain the important mechanism mediating the beneficial effects of exercise on memory? Exercise improves memory both in the very short term, and over the long term. This may be as simple as increased blood flow delivering more of the nutrients and signals that spur brain tissue into greater activity, though there are other mechanisms to consider as well. The research here adds evidence for the effect to result from better blood flow to memory-related areas of the brain.
Scientists have collected plenty of evidence linking exercise to brain health, with some research suggesting fitness may even improve memory. But what happens during exercise to trigger these benefits? New research that mapped brain changes after one year of aerobic workouts has uncovered a potentially critical process: Exercise boosts blood flow into two key regions of the brain associated with memory. Notably, the study showed this blood flow can help even older people with memory issues improve cognition, a finding that scientists say could guide future Alzheimer's disease research.
The study documented changes in long-term memory and cerebral blood flow in 30 participants, each of them 60 or older with memory problems. Half of them underwent 12 months of aerobic exercise training; the rest did only stretching. The exercise group showed a 47 percent improvement in some memory scores after one year compared with minimal change in the stretch participants. Brain imaging of the exercise group, taken while they were at rest at the beginning and end of the study, showed increased blood flow into the anterior cingulate cortex and the hippocampus - neural regions that play important roles in memory function.
Evidence is mounting that exercise could at least play a small role in delaying or reducing the risk of Alzheimer's disease. For example, a 2018 study showed that people with lower fitness levels experienced faster deterioration of vital nerve fibers in the brain called white matter. A study published last year showed exercise correlated with slower deterioration of the hippocampus. "Cerebral blood flow is a part of the puzzle, and we need to continue piecing it together. But we've seen enough data to know that starting a fitness program can have lifelong benefits for our brains as well as our hearts."