One of the best ways to strengthen your brain is to exercise it physically and men- tally—at the same time. Exercising your brain by thinking—working out problems—is beneficial. And exercising your brain by taking it for a walk is also good. The hippo campus, the part of the brain concerned with memory, grows as your body gets fitter. But now German scientists have shown that if you do both at the same time, you reap even greater benefits. For example, if you bicycle or walk while learning a new language, the vocabulary tends to stick in your memory longer. Note that this is not the same as multitasking, where you’re trying to do two mental activities at once, like reading a book while listening to a lecture. It’s the combination of physical and mental activity that is key.