Healthy aging quiz: What's normal aging and what's not?

About half the adults age 65 and older in the United States have most of their natural teeth. And the number of adults with natural teeth continues to grow, thanks to fluoride in drinking water and toothpaste, advances in dental care, and improved oral hygiene. Don't accept cavities and gum disease. You can improve your chances of keeping your teeth as you age by brushing and flossing daily, and by seeing your dentist every six months.

As you age, your internal clock — your circadian rhythm — adjusts, making you sleepy earlier in the evening. As a result, you might find that you go to bed earlier and wake up earlier. You'll likely need the same amount of sleep as you age, but getting those same quality sleep hours is more difficult because you don't sleep as soundly.

As long as you're waking rested and refreshed, your changing sleep schedule shouldn't be a cause for alarm. If you're having trouble sleeping, it could be something more than typical aging changes. Insomnia is the most common sleep problem, no matter what your age. Stick to a regular schedule — wake up and go to bed at the same time each day. Avoid napping more than 20 minutes during the day. Exercise can help you maintain your sleep schedule. Also try sleeping in a cool room, using eyeshades and reducing or eliminating the amount of caffeine, alcohol and other liquids you consume in the evening hours.

A satisfying sex life is possible for adults of any age. Older adults might find that medications, illness or injury create problems when it comes to having sex. But most of these problems can be treated, either by treating your illness, changing your medication or changing sexual positions. Don't abandon sex solely because of age. See your doctor if you have concerns — don't accept sexual difficulties as a sign that you're too old for sex.

Though memory-related diseases, such as Alzheimer's, are more common in older adults, they aren't inevitable. Many older adults maintain sharp minds. Occasional memory lapses are common, but if you find you're misplacing your keys or forgetting names and appointments more frequently, talk to your doctor about your concerns.

Depression and anxiety can also cause memory problems. If you feel sad, lonely or worried, you might find it harder to concentrate. Talk to your doctor or a counselor about your feelings.

In the meantime, keep your mind fit and agile by giving it a workout. Exercise your mind with a new hobby or skill — take up that musical instrument you never had the time to try. Or try word games, such as crossword puzzles.

Constipation — passing harder stools less often — is more common in older adults. Most of the time constipation isn't serious. Eating high-fiber foods, such as fruits and vegetables, drinking plenty of water and getting regular exercise can usually relieve constipation.

However, see your doctor if you have fewer than three bowel movements a week. Other signs of something more serious include:

• Difficulty passing stools
• Stools that are lumpy or hard
• A feeling of not being able to empty your bowels

Many people with chronic joint pain assume their aches are just part of growing older, so they don't see their doctors. Pain, swelling and stiffness in a joint that lasts for more than two weeks may be a sign of arthritis. See your doctor if joint pain bothers you. Identifying and treating arthritis early may mean less pain and disability in the future.

Older adults may have a higher risk of illness, but that doesn't limit their activities. Only about 34 percent of adults 65 or older in the United States report that their daily activities are limited by chronic disease. And that number is steadily declining.

If you're worried that illness in your old age will leave you dependent on others, take steps now to ensure your independence. Exercise daily to keep your bones and muscles strong and work with your doctor to manage your chronic health conditions. If you do have a disability that could one day make it difficult to care for yourself, plan now so that you're ready when the time comes for assistance. Explore options for long term care and ways to finance the type of care you choose.

At least one in every 10 people age 65 and older has urinary incontinence, and it's even more common in older women. But it isn't caused by aging. Instead, urinary incontinence can be caused by a number of conditions, such as urinary tract infections, weakened bladder muscles or certain medications.

Most causes of urinary incontinence are treatable. Talk to your doctor about your concerns, especially if loss of bladder control is keeping you from enjoying everyday activities.

The lenses in your eyes become stiffer and less elastic in your 40s. This makes it more difficult to focus on nearby objects or small print. You may start holding reading material at arm's length. You may also get headaches and eye fatigue from reading or other close work. The sharpness of your vision — your eyes' ability to distinguish fine details — also gradually declines with age. If you're noticing changes in your vision, schedule an eye exam with an ophthalmologist or optometrist. Otherwise, have your eyes checked every two to four years, or every year if you already wear glasses. Your doctor may recommend more frequent eye exams if you're at risk of certain eye diseases.

While it may be a common-held belief that getting older means being less happy, depression isn't caused by aging. Everyone feels sad from time to time, but feeling hopeless and worthless is a sign of something more serious. Help and treatments are available. Talk to your doctor about your feelings.