There isn't a definitive answer (yet), but what experts do know is that we all need a brain fitness regimen to stay sharp as a tack.

You know you need to keep your body fit with physical activity. But don't forget about your brain. While improving your physical fitness aids your brain, so too does improving mental fitness, and experts say it's never too early—or late—to start a brain fitness regimen to stay sharp into old age.

Brain health is something that needs to be on everybody's radar, because while your brain is technically an organ, it's similar to the other muscles in your body: If you don't use it, you'll lose it.

"Studies show that staying mentally fit is important for long-term cognitive health, but the difficulty is figuring out exactly how best to do it," says Aaron Seitz, Ph.D., professor of psychology and director of the Brain Game Center at the University of California in Riverside.

Enter: brain training games. In recent years, there's been an explosion of these games on the market (just type "brain games" or "memory games" into your app store and you'll see hundreds of options). But the available research isn't entirely clear about which brain games work best (and for whom), if they work enough to make a substantial impact, or if they even work at all. Hear what psychologists and neuroscientists have to say about brain games, and learn their preferred ways to keep that brain fit on the daily.

How Cognition Changes as We Age

Everybody jokes about not being able to remember names as easily or forgetting where they put the car keys as they get older, but unfortunately there's truth behind the teasing. "As you age, your cognitive skills tend to decline," says Nicole M. Avena, Ph.D., assistant professor of neuroscience at the Mount Sinai School of Medicine in New York City and visiting professor of health psychology at Princeton University in Princeton, N.J. She says natural signs of mental aging can often include having a weaker memory or hand-eye coordination compared to when you were younger.

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Surprisingly, these changes start happening as early as your 20s. "Almost every aspect of your ability to remember, tend to things and process information quickly declines," Seitz says. 

Of course, not everybody's brain changes the same way, at the same time or at the same pace, which is why you see wide variability in mental fitness among older adults. But why is that? "While genetics and other factors play a role, one component of why people remain cognitively fit for longer may be the activity their brain has engaged in," Seitz says.

Should You Play Brain Games? Here's What the Science Suggests

To provide that activity, people have turned to brain games. They range from apps to physical board games and puzzles, and there's no question people do get better at these games, Seitz says. The real question, though, is whether playing these games is just making you better at the specific game or actually helping you improve real-world tasks that involve memory, attention and other aspects of higher cognition.

So far, studies have been mixed, with half finding positive results, the other half finding none. "Because the training methods in all of this research are different, it's hard to draw conclusions," Seitz says.

One factor that can diminish the efficacy of these games is individual differences among people. "We suspect that different people will need different types of training," Seitz says. "If you think about diet and exercise routines, some things work better for some people than others, and the same is true with brain games." That's why the Brain Game Center is currently enrolling 30,000 individuals to find out not only if brain games work, but why they work and for whom they're best suited. (If you're curious and want to participate, use this link.)

Regardless, many experts do recommend brain games. "While some studies show that brain training games are not effective, the recollection and work that the brain does during these games keeps your mind fresh and alert," Avena says, adding that while anybody can benefit from them, they're most beneficial for older adults because they have declining cognitive function. As a result, "the brain functions that you practice during these games—and the repetition of them—can help improve response time and sharpness of your brain."

Some helpful games to try? You don't need to look for something trendy or spend a lot of money. Avena points to familiar (and much-loved) activities like playing Sudoku and doing crossword puzzles, which can keep the brain sharp by keeping focus and concentrating to find the right answer. 

Meanwhile, if you're challenging your brain to do something new like learning another language, you'll help improve brain structure and neuroplasticity, and diving into these new-to-you tasks certainly holds merit.

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What the Brain Needs Most: Something New Every Day

One reason these games don't always prove effective in studies is many don't challenge the brain enough. "Many lack the complexity and level of engagement that charges the brain forward," says Stacy Vernon, M.S., LPC, a clinician with the Brain Performance Institute and The BrainHealth Project at the University of Texas at Dallas.

This is because the brain thrives on regular challenges. "If you want to be proactive about brain health, the most consistent advice is to learn a new thing every day," Seitz says. 

That may sound extreme, but the point is to keep challenging the brain, especially when you get good at something. Once that happens, you need to try another activity that forces you to start over and be challenged all over again. For instance, this might mean learning a new instrument or a new language. "It's the challenge, not just the activity; that's the most important thing," Seitz says. 

The best way to know if you're being challenged? If you're messing up. "If you're making mistakes, correcting them and improving, that's the activity you should be doing for your brain," he says. 

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The Bottom Line on Brain Games (for Now)

Are brain games the right call for you? While the scientific jury's still out on their definitive efficacy for mental fitness and longevity, playing them certainly can't hurt. If you want to try them, look for brain games that provide a challenge and have research to back them like BrainHQ, which Vernon and her colleagues have used in their research. Avena also recommends figuring out what you want to accomplish with the game and searching for games that address your concerns. Then do them consistently, perhaps four to five times a week for as long as 30 minutes a day, Vernon recommends, adding that consistency is more important than duration.

 Just don't think these games are the only activity in your brain fitness regimen. "If you pigeonhole your brain health activity into 10 minutes a day with these games, you're missing out on the other 23 hours and 50 minutes you could be working on your brain health," Vernon says. Activities like having regular social interactions, finding your purpose in life, getting enough sleep, eating healthy and exercising also help.