Similar to a muscle, your brain grows stronger with regular use and frequent challenges, developing what is known as cognitive reserve. A brain that isn’t stimulated will grow smaller and, according to research published in Lancet Neurology, may be associated with a greater risk of Alzheimer’s disease.

I hope this list will encourage you to challenge your brain and seek fresh experiences that keep your brain younger while adding life to your years.

1. Quiz Yourself on What You Read

We often read things without the expectation of ever recalling them, which causes us to read lazily. But what if you knew you would be quizzed on what you read—maybe later that day or the next? As a regular exercise, read an interesting story in the newspaper or on a favorite website, set an alarm for a few hours later, and write down a summary of the main points from memory.

2. Travel Without GPS

We’ve become dependent on our phones to help us navigate the physical world we embody. Though being directed is convenient, navigating and orienting activates important parts of your brain and presents a great opportunity to challenge your memory. If you’re heading someplace new, pull up the directions on your phone before you leave and look them over with the intent to remember. Navigate to your destination by your new mental map—only using your GPS if you become deeply lost.

3. Memorize Important Facts

Having important facts memorized and at the tip of your tongue is handy and a great way to keep your brain agile. Some useful items to memorize are names of new people you meet, birthdays of loved ones and friends, and your credit card and license plate numbers. Before cellphones, we may have had dozens of phone numbers committed to memory—do you have the numbers of your most important contacts memorized?

4. Put Yourself in Chaotic Environments

As humans, we naturally gravitate toward ease and comfort, but with the right attitude, you can learn to see chaos as a game to be played rather than an annoyance. The next time you’re around a group of kids, resist the urge to run away from their loud and rambunctious activities—put yourself right in their midst and try to keep up.

5. Strike Up Conversations With Strangers

The easiest conversations are with those you know well, and if you’re like most people, you naturally gravitate toward those people when put in a new environment. How might it stretch you to have a conversation with a new person every day? The improvisation of small talk is like mental jujitsu for your brain—a challenge sure to keep your mind fresh and active.

6. Use Your Nondominant Hand

Anything you can do to break your normal rhythms and patterns is going to challenge your brain in novel ways. Something I tried recently was brushing my teeth with my nondominant hand for a month. By the end, it had become less awkward, demonstrating how the brain grows and adapts to the changes you throw at it.

7. Shop Without a List

See if you can make it through your workday without a to-do list or through a grocery trip without relying on a pre-made list of items. Use whatever memorization strategy you like to recall the items you would have written down. You might think memorizing such items will crowd out the important stuff, but I’ve found that it enhances my attention in all areas of life.

8. Solve Math Problems in Your Head

The next time you’re approached with a tricky math problem—whether at work, at the grocery store, or when paying a bill—don’t reach for the calculator app on your phone or even a piece of paper. Working out the math in your head is like calisthenics for your working memory. Working memory is the part of your brain that holds short-term information at your easy disposal, helping you do more complex operations.

9. Read for an Hour

Another aspect of brain health is mental stamina. In the same way an untrained person can only jog for a few minutes before being winded, an untrained brain will tire after a few minutes of mental effort. Instead of scrolling on your phone from one short-form video to another, challenge yourself with increasingly longer sessions on a single task—reading is just one of many ways to improve concentration.