Did you know that as we age, the memory parts of our brains actually shrink?

Puzzles and crosswords can keep your mind sharp, but here are four other ways to exercise your brain.

1. Go for a walk.
Research shows that walking for about 40 minutes three times a week will help increase the size of the hippocampus, the part of the brain responsible for your memories.

2. Drink coffee.
A study in Australia found that coffee can actually sharpen your focus and memory. Filtered black coffee works best— just remember to go easy on the milk and sugar.

3. Laugh.
Studies show that laughing for about 20 minutes will boost your short-term memory. Watching funny videos, a TV show or even talking to a friend who makes you smile will do the trick.

4. Listen to music.
Researchers in Rome found that listening to Mozart increased brain wave activity linked to memory by activating the nerve cells in the brain, and boosting concentration and cognitive function.