If you’ve been paying attention to the news about brain health, you’ve probably noticed an uptick in claims that a Sudoku a day can keep Alzheimer’s at bay. Others (cough cough, Mom) swear by crossword puzzles. Are brain games the key to staving off cognitive decline?

The short answer is maybe, but we don’t know enough yet about which kinds of mentally-challenging activities are best for the brain such that they might delay cognitive decline or even boost cognitive agility. Plus simply doing Sudoku or crossword puzzles without making significant lifestyle changes at the same time — better nutrition, regular physical exercise, and sleep and stress management — hasn’t been proven to do anything beyond passing the time during which you do them enjoyably. The longer answer is that at some point we will figure out exactly which kinds of brain training are best for boosting brain power, but for now, the science is still in its infancy.

Here’s what we do know. Last year, in 2017, scientists at Johns Hopkins conducted a study in which subjects were asked to watch a series of flashing squares while hearing a series of corresponding letters of the alphabet. They were then asked to indicate both the letter of the alphabet and the placement in space of the second-to-last square. The researchers took this further, asking participants to identify which was the third-to-last letter and square. The full results can be read here, but what it showed is that the kind of brain training a subject does matters. Simply tracking an object in space and remembering its placement is not enough. The simultaneous recall of the letters worked much better to boost cognitive health.

Then, just this week, NPR delivered a doozy of a news alert onto the screens of all of its listeners: “Best Brain Game To Stave Off Alzheimer’s Could Be Your Job,” it said. The article in question, featured on Morning Edition, quotes Jessica Langbaum, a specialist in Alzheimer’s prevention, who said, “My job is my daily cognitive training.” She went further, not exactly poo-pooing Sudoku as an Alzheimer’s cure-all, but definitely calling the scientific proof of its efficacy into question. “Just sitting down and doing Sudoku isn’t probably going to be the one key thing that’s going to prevent you from developing Alzheimer’s disease,” she said.

Moreover, doing only one type of puzzle or another is not the key either. The brain needs to be exercised, just like any other muscle in the body. When you go to the gym to work out your biceps, for example, you don’t just do the same single machine every day. You switch it up, pulling down, pushing up, squeezing in and out, then maybe adding some free weights for good measure. Exercising the brain is no different. Repetition of the same task over and over won’t turn you into Einstein. Pondering the mysteries of the universe, however, might bring you a step closer.

What all of this new research means for the future of early retirement is still unknown. If you like your job and want to keep doing it well into your seventies and even eighties, maybe you should consider keeping those golf clubs in the closet for a little while longer. Particularly if you want to remember the score. But however you choose to live out the last decades of your life, whether at work or at play, what’s becoming increasingly clear is that a decline in cognitive abilities is not an inevitable byproduct of aging: by engaging your brain in a variety of challenging tasks, while also maintaining physical, mental, and nutritional health as well, no future Sudoku or crossword puzzle will be beyond your capabilities. (Except maybe Saturday’s. Saturday’s crossword puzzle is hard for everyone.)

Editor’s note: This is the fourth in a 7-part series created by Neurotrack about maintaining your cognitive health and well-being. It’s Neurotrack’s way of marking World Alzheimer’s Month. The science is clear, the evidence unequivocal: the new habits you start today can make an enormous difference in the health of your brain of tomorrow. Next week we will discuss sleep: how to get more of it and why it’s important for maintaining the brain. Please check back here to learn more.