Taking Care of Your Brain
What aging can bring: Forgetfulness, decline in mental agility, risk of Alzheimer's disease.
What the research shows: Doing things that hit both the left and right sides of the brain, like word puzzles plus mazes and visuals, has been proven to build brainpower. Swedish researchers found that subjects who exercised at least 20 minutes two or more times a week at midlife reduced their risk of developing Alzheimer's and other forms of dementia later by 60 percent. On the nutrition front, a study at the Louisiana State University Health Sciences Center showed that an essential omega-3 fatty acid counteracts the brain's production of neuron-damaging amyloid proteins.
What you can do: Challenge yourself mentally and physically; as little as 10 minutes of exercise a day may lower your risk of Alzheimer's. Eat antioxidant-loaded foods, such as almonds, leafy greens, and blueberries; and if you don't eat enough fatty fish rich in omega-3 acids, like salmon (at least two servings a week), ask your doctor about taking a daily 1,000-milligram fish-oil supplement.

Taking Care of Your Skin
What aging can bring: Wrinkles, brown spots, skin cancer.
What the research shows: Sun exposure and smoking can cause the loss of collagen and elastin and changes in DNA that can lead to skin cancer. Antioxidants will help keep damage at bay by allowing the skin to repair itself.
What you can do: Don't smoke, drink at least one cup of green tea (a powerful antioxidant) daily, and be sure to get enough vitamins C and E. Use a broad-spectrum sunscreen (one that protects against both UVA and UVB rays) of at least SPF 30 every day; check the label for one or more of these ingredients: titanium dioxide, zinc oxide, and Mexoryl. Topical application of green tea and vitamins C and E, which are found in many anti-aging products, helps boost the skin's ability to fend off free-radical damage.

Taking Care of Your Lungs
What aging can bring: Loss of aerobic capacity.
What the research shows: At any age, you can maximize your aerobic capacity with regular exercise. And the fitter you are, the easier it is to perform daily tasks. If you are in good shape, you may need only 50 percent of your aerobic capacity to do something like push a vacuum, depending on your age and sex.
What you can do: Even walking at a brisk pace on a regular basis can help maintain aerobic capacity in older adults. (Always consult your physician before starting an exercise program.)

Taking Care of Your Muscles
What aging can bring: Decreases in strength and muscle mass, loss of flexibility, loss of balance.
What the research shows: If you're sedentary, you will start losing strength after age 50 at a rate of 2 to 5 percent per decade. But if you keep using your muscles, through activities like weight training, you can maintain strength and flexibility even into your 90s. It's also important to work on balance, which falters with age, and to keep muscles agile so you can react quickly.
What you can do: Add resistance moves to your workout, and mix in some fast, dynamic exercise as well—dance classes, tennis, volleyball. Good balance builders are one-legged squats and even something as simple as standing on one foot and then the other while you brush your teeth.

Taking Care of Your Heart
What aging can bring: Cardiac disease, heart attack, stroke.
What the research shows: High blood pressure is the number one culprit when it comes to heart trouble. (The ideal number is 115/76.) A diet high in sodium is linked to high blood pressure. As for cholesterol, the numbers to shoot for are a total count of less than 200, with an HDL greater than 60 and an LDL around 70. The two risk factors are linked: High blood pressure causes little nicks to form in arteries, which the body then plasters over with cholesterol. That attracts inflammatory cells, creating arterial plaque that can lead to clots, heart attacks, and strokes.
What you can do: Keep your diet low in salt and saturated fat and high in fruits, vegetables, and whole grains. Aim for 30 minutes of aerobic activity four or five days a week.

Taking Care of Your Bones
What aging can bring: Osteoporosis, fractures.
What the research shows: In your 30s, your body stops storing calcium, so if you don't get enough in your diet, your body will start depleting its stores. Another cause of brittle bones is lack of exercise. Bone is live tissue, like muscle, and it needs to be stressed to grow. Anything that puts weight—stress—on the bones will help build bone mass, but you want to stress them in as many different ways and directions as possible.
What you can do: Activities that include a variety of movements, like racquetball and dancing. Women need between 1,000 and 1,200 milligrams of calcium in their daily diet or as a supplement, along with 400 international units (IU) of vitamin D and 350 to 400 milligrams of magnesium.