In addition to keeping you physically fit, exercise may protect your brain, according to a new study. Research reported in the current issue of the journal Genes and Development shows that running can promote brain cell survival in animals with neurodegenerative disease. Previous work had indicated that running can boost brain cell growth in normal mice. In the new study, however, scientists studied mice with a condition similar to the disorder ataxia-telangiectasia (A-T), which in humans leads to a loss of motor control that typically leaves patients wheelchair-bound. (Though rare, A-T shares properties in common with diseases like Alzheimer¿s.) Those A-T mice that ran, they found, exhibited higher levels of cell survival than did their non-running counterparts. "In sedentary A-T mice it appears that most newly born brain cells die," team member Carrolee Barlow notes. "We don¿t understand that fully, but it probably has something to do with an inability to cope with oxidative stress. Running appears to ¿rescue¿ many of these cells that would otherwise die," she continues. "It suggests that staying active may help delay progression of neurodegenerative conditions."

Researchers hope that further investigation will reveal exactly how exercise helps brain cells to survive. "It must be altering brain chemistry¿altering levels of particular hormones or growth factors, perhaps," Barlow muses. "If we can identify the specific molecules responsible for running¿s effects, those molecules should point to new drug strategies to treat A-T and other neurodegenerative diseases."