True, there's no home-gym equipment designed to build up your brain muscle. But a simple walk will do.

A new study shows that regular cardiovascular exercise can enlarge the hippocampus -- a brain structure vital to memory function.

Fit Body, Better Memory
As we age, our brains tend to shrink, and our memory can wither in the process. But a new study shows that an aerobically fit person has a larger hippocampus and performs better on spatial memory tests than a less fit subject. In the study, being more fit did not slow the rate of hippocampal shrinkage once it began, but it meant that people generally had more to work with once shrinking started. And that means less total deterioration overall. Find out what types of exercise provide brain-boosting benefits.

Banish Brain Downsizers
Related research suggests that exercise may even help restore lost brain volume and cognitive function in people with early-stage Alzheimer's disease, possibly because exercise increases cerebral blood flow and boosts the birth of new brain cells. Here are some other cognitive-health tips to consider:

• Stamp out stress. Chronic stress can be a real brain drain, and troubled finances may be one major cause. Watch this video to learn what the YOU Docs say about managing the stress that comes from money woes.
• Ditch depressing thoughts. Find out why kicking out blue thoughts may help your memory as well.
• Minimize the mai tais. Some studies suggest that alcohol abuse may shrink the hippocampus. But can moderate drinking actually help cognition? Find out here.

Are you in a rut? Take this quick mental test and get some simple ideas for boosting your brainpower with new challenges.

Aerobic fitness is associated with hippocampal volume in elderly humans. Erickson, K. I. et al., Hippocampus 2009 Jan 2. [Epub ahead of print]