Keep Your Brain Fit

The long-held assumption that we lose about 10 percent of our neurons per decade is not true. "Remarkably, there are as many neurons in a healthy 80-year-old brain as there are in a young adult's," says Michela Gallagher, PhD, professor of psychological and brain sciences at Johns Hopkins University. "When you're 50 or 60 and forget something, you think, 'Oh my God, my brain's falling apart.' But if you've still got all your neurons, the likelihood that you can prevent memory loss is much greater than if your brain had substantially deteriorated."

The magic memory pill has yet to be found, but science does know that regular exercise, social engagement, and education all help keep the brain sharp as you age—"not just in terms of current memory," says Gallagher, "but also in reducing the risk of Alzheimer's disease."