Many older adults also show significant improvements in their physical and cognitive health over time, according to a new study. The reason why seems to lie in how they think about aging. People who viewed getting older positively were more likely to show improvements in their cognitive skills and their walking speed. By contrast, folks in the study who held more negative ideas about aging tended to see a decline in these skills. That suggests people's beliefs can have a dramatic effect on their biology, the researchers say. "Our findings suggest there is often a reserve capacity for improvement in later life," said study co-author Becca Levy. "And because age beliefs are modifiable, this opens the door to interventions at both the individual and societal level." The new study included more than 11,000 adults aged 65 and up. 45 percent of the participants saw a positive development in either their scores on a cognitive test or their walking speed"a critical measure of fitness. Notably, when the researchers averaged the participants' scores, they saw an expected decline in ability as people aged. But on the individual level, that picture didn't hold up for everyone. "Many people equate aging with an inevitable and continuous loss of physical and cognitive abilities," Levy said. "What we found is that improvement in later life is not rare, it's common, and it should be included in our understanding of the aging process."