According to an article on WebMD, Mayo Clinic researchers have found that a combination of exercise and computer use late in life may be protective against memory loss:
The study shows that both physical exercise and mental exercises such as reading books, playing games, and computer use are associated with a lower risk of mild cognitive impairment; a combination of these activities appears to pack a one-two punch that is even more beneficial.
The Mayo Clinic study, which involved 926 people ages 70 to 90, showed that: (1) people who engaged in moderate exercise were 36 percent less likely to have mild cognitive impairment than people who didn't exercise; and (2) people who engaged in any amount of computer use were 44 percent less likely to have mild cognitive impairment than people who do not use a computer. (Note to readers: The study didn't specifically mention the use of Plants vs. Zombies - or power walking for that matter - but "PvZ" is an incredibly fun game.)
Previously: Studying ways to combat mental decline in aging