Researchers have uncovered part of why exercise and brain health are connected.
Henriette van Praag, neuroscience researcher at the National Institute on Aging, says their team’s findings provide “another piece to the puzzle.” The report released to the journal Cell Metabolism shows that running releases a protein that seemingly generates new cells and connections in the brain’s memory center.
Van Praag and her team had begun searching broadly for factors in the link between fitness and memory to follow up on previous research that had established the connection. They soon found a protein called cathepsin B while searching for substances produced by the muscles in response to exercise.
Cathepsin B is known to be associated with cell death and some diseases. Experiments showed that its levels rose in mice that spent increased time on their exercise wheels. The protein caused new cell growth and connections in the hippocampus of the mice so that they performed more effectively on a memory test. This test required them to swim to a platform hidden just beneath the surface of a small pool.
Upon broadening their research, the team found out the exercise led to raised levels of cathepsin in Rhesus monkeys as well.
The next step was to test for these results in humans, so the team picked 43 sedentary university students. Half of the students continued their regular habits while the other half began rigorous treadmill workouts several times a week. Like the mice, the exercising students had higher levels of cathepsin and improved in a memory task: reproducing a geometric pattern they had seen after several minutes had passed.
Neurologist and team member Dr. Emrah Duzel said, “Those individuals that showed the largest gains in memory also were those that had the largest increase in cathepsin. Van Praag added that cathepsin is likely just one of several factors behind the connection between exercise and brain function, but that this is a step in the right direction.
Van Praag also cautions that trying to raise cathepsin levels artificially might be dangerous as cathepsin is also produced by tumor cells and has been linked to brain plaques associated with Alzheimer’s, but some jogging can be a good way to raise cathepsin levels naturally, promoting the brain’s memory function.