Doing puzzles and listening to classical music might improve your concentration momentarily, but they don’t actually make you any smarter. That is, they don’t improve your long-term brain function, according to The Economist’s interview of Nicholas Spitzer, a professor of neuroscience at the University of California and editor-in-chief of BrainFacts.org.

“Let me dispel a brain development myth,” Spitzer told The Economist. “Many people think classical music is going to enhance brain function (the Mozart effect) or playing particular games sharpens one’s cognitive function. These theories have been looked at in detail and they don’t stand up. It is disappointing in a way, but what we have learned is that exercise is the key thing for brain function.”

By exercise, he means general activity and—more importantly—exposure to sunlight. In a recent study (paywall), he found that rats produced different brain-altering chemicals based on environmental factors. He thinks that our brains change their behavior (like “a railway switching yard”) based on environmental factors to help us conserve energy during winter. But when we give in to the evolutionary impulse to stay inside under the covers, we give our brain a further signal that it’s time to use as little energy as possible. This feedback loop, he says, is what causes Seasonal Affective Disorder, a type of depression that affects otherwise healthy people during the dark winter months.

So to keep your brain at tip-top shape, you should stay active. That gives your body cues to devote lots of resources to cognitive function. Then again, puzzles do help with some specific things, like increasing verbal aptitude (paywall) and helping you learn a new subject more quickly. So as long as you get plenty of time outside, there’s no reason to drop the sudoku.

And getting into bed, for certain purposes at least, can help brain function, too. A recent study found that female orgasms trigger an increase in blood flow to all regions of the brain, improving overall cognitive performance. Keep that in mind when you’re figuring out how to get that exercise in.