Gretchen Reynolds asks, which exercise is best for the brain?
For the first time, scientists compared head-to-head the neurological impacts of different types of exercise: running, weight training and high-intensity interval training. The surprising results suggest that going hard may not be the best option for long-term brain health. [...]
So for the new study, which was published this month in the Journal of Physiology, researchers at the University of Jyvaskyla in Finland and other institutions gathered a large group of adult male rats. The researchers injected the rats with a substance that marks new brain cells and then set groups of them to an array of different workouts, with one group remaining sedentary to serve as controls.
Some of the animals were given running wheels in their cages, allowing them to run at will. Most jogged moderately every day for several miles, although individual mileage varied.
Others began resistance training, which for rats involves climbing a wall with tiny weights attached to their tails.
Those rats that had jogged on wheels showed robust levels of neurogenesis ["the creation of new brain cells in an already mature brain"]. Their hippocampal tissue teemed with new neurons, far more than in the brains of the sedentary animals. The greater the distance that a runner had covered during the experiment, the more new cells its brain now contained.
There were far fewer new neurons in the brains of the animals that had completed high-intensity interval training. They showed somewhat higher amounts than in the sedentary animals but far less than in the distance runners.
And the weight-training rats, although they were much stronger at the end of the experiment than they had been at the start, showed no discernible augmentation of neurogenesis. Their hippocampal tissue looked just like that of the animals that had not exercised at all. [...]
Dr. Nokia and her colleagues speculate that distance running stimulates the release of a particular substance in the brain known as brain-derived neurotrophic factor that is known to regulate neurogenesis. The more miles an animal runs, the more B.D.N.F. it produces.
"The mental benefits of exercise, writes Discover, "have been studied in depth, and go far beyond a clear head and a shot of endorphins:"
Running won't always drastically expand our lifespans. But the study [published in the journal Cell Reports] points to a possible mechanism to fight diseases that break down the connections in our brains, such as Alzheimer's.
The key, the researchers say, is the chemical cocktail that floods our brains after a good workout. They identified a specific protein, VGF, that was likely at play in this case. VGF is released after we exercise, and it had been found to have some antidepressant properties. Based on their findings, the researchers say that VGF also promotes the regrowth of myelin in our nervous system.