Getting old is getting expensive. Really expensive. Think billions—hundreds of billions, even. And according to an April 2013 article in the New England Journal of Medicine, it’s just going to get more so in the coming decades. Why? The incidence of dementia is on the rise in our country and it is a pricey disease. There are so many costs associated with dementia—medication, health care, home care, etc. It’s not just as simple as taking a pill and calling your doc in the morning.QUIZ: How Fast Are You Aging?Fortunately, dementia is a chronic disease. “Fortunate?!” you say. Yup, fortunate, because like many chronic diseases, dementia is in part lifestyle-driven, which means that you can help control it. There is an abundance of research, and more emerging everyday, that what you eat, how active you are and how you manage your stress today all contribute to your risk of dementia later in life.Let’s break down what you can do.Watch What You EatBrain food is good food. Specifically, foods rich in Omega-3 fatty acids are great for your brain. Yet another reason to eat salmon and nuts, especially walnuts. Food choices also impact your stroke risk, which can affect your risk of vascular dementia. (Dementia is not just a code word for Alzheimer’s. There are actually different kinds of dementia.) A diet high in sodium, for example, is known to increase your stroke risk. So to minimize that risk, plant some yummy herbs this spring and sprinkle those into your meals instead of reaching for the salt shaker.COLUMN: The Many Benefits of the Mediterranean DietExercisePut on those running shoes and get moving! Turns out that the recommendation from the American Heart Association to take 10,000 steps a day isn’t just good for your heart: It’s good for your mind as well. A study published this winter in the Annals of Internal Medicine* found that participants who exercised in their middle age could reduce their risk of later developing dementia.Kick BackTake your pick: Maybe it’s yoga, or meditation, or the New York Times crossword puzzle. Do whatever makes you feel connected and engaged. A growing body of research suggests that leisurely activities that keep you busy—body and mind—help decrease your risk of cognitive decline. Relaxing fun now, health later. Not bad, eh?QUIZ: Hobbies for Happiness and Health