At 99, Betty White was still as sharp-witted as ever. Perhaps that was because she had so many pets in her lifetime — estimated at 24 as an adult, including her last dog Pontiac, a rescue pup.

A new study to be presented at the American Academy of Neurology's annual meeting in April reveals that people who have a pet, especially for five years or longer, experience measurably less cognitive decline than those with no pets.

The researchers looked at cognitive data from 1,369 older adults and found that pet owners did better on tests of subtraction, numeric counting, and word recall.

Previous studies have suggested that the human-animal bond decreases stress and blood pressure, both of which can have negative effects on cognition.

Other possible brain-boosting benefits of pets may come from increased exercise and social interaction associated with owning a dog, and a pet's ability to ease its owner's feelings of loneliness and depression.

If you're thinking about getting a pet, ask your local animal shelter about adopting. And it doesn’t have to be a cat or dog; consider an "alternative pet" such as a rabbit or a parrot.

Not in the market for a furry companion? There are 33 other choices you can make that have been shown to increase long-term cognitive performance. They range from routine physical activity and achieving normal blood pressure to fasting correctly, enjoying speed-of-processing games, and taking certain supplements such as phosphocreatine.

All 33 of these suggestions are discussed in my upcoming book "The Great Age Reboot." (Check out info@GreatAgeReboot.com).