Merck manual of health and aging

They are to be expected and are generally unavoidable. For example, as people age, the lens of the eye thickens, stiffens, and becomes less able to focus on close objects, such as reading materials a disorder called presbyopia Causes In refractive disorders, light rays entering the eye are not focused on the retina, causing blurred vision. The shape of the eye or cornea or age-related stiffness of the lens may decrease the This change occurs in virtually all older people.

Thus, presbyopia is considered normal aging. Other terms used to describe these changes are usual aging and senescence. Average life expectancy has increased a lot, but maximum life span has increased little if at all.

Exactly what constitutes normal aging is not always clear. Changes that occur with normal aging make people more likely to develop certain disorders. However, people can sometimes take actions to compensate for these changes. For example, older people are more likely to lose teeth. But seeing a dentist regularly, eating fewer sweets, and brushing and flossing regularly may reduce the chances of tooth loss.

Thus, tooth loss, although common with aging, is an avoidable part of aging. Also, functional decline that is part of aging sometimes seems similar to functional decline that is part of a disorder. For example, with advanced age, a mild decline in mental function is nearly universal and is considered normal aging. This decline includes increased difficulty learning new languages, decreased attention span, and increased forgetfulness. In contrast, the decline that occurs in dementia Dementia Dementia is a slow, progressive decline in mental function including memory, thinking, judgment, and the ability to learn.

Typically, symptoms include memory loss, problems using language and For example, people who are aging normally may misplace things or forget details, but people who have dementia forget entire events. People with dementia also have difficulty doing normal daily tasks such as driving, cooking, and handling finances and understanding the environment, including knowing what year it is and where they are. Thus, dementia is considered a disorder, even though it is common in late life.

Certain kinds of dementia, such as Alzheimer disease Alzheimer Disease Alzheimer disease is a progressive loss of mental function, characterized by degeneration of brain tissue, including loss of nerve cells, the accumulation of an abnormal protein called beta-amyloid For example, brain tissue obtained during autopsy in people with Alzheimer disease looks different from that in older people without the disease.

So the distinction between normal aging and dementia is clear. Sometimes the distinction between functional decline that is part of aging and functional decline that is part of a disorder seems arbitrary.

For example, as people age, blood sugar levels increase more after eating carbohydrates than they do in younger people. This increase is considered normal aging. However, if the increase exceeds a certain level, diabetes Diabetes Mellitus DM Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar glucose levels to be abnormally high.

Urination and thirst are In this case, the difference is one of degree only. Healthy aging refers to postponement of or reduction in the undesired effects of aging. The goals of healthy aging are maintaining physical and mental health, avoiding disorders, and remaining active and independent. For most people, maintaining general good health requires more effort as they age. Developing certain healthy habits can help, such as. The sooner a person develops these habits, the better.

However, it is never too late to begin. In this way, people can have some control over what happens to them as they age. A decrease in the percentage of older people residing in nursing homes even though the percentage of people who are over age 65 and who are over age 85 has increased in the general population. Gerontology is the study of the aging process, including physical, mental, and social changes.

The information is used to develop strategies and programs for improving the lives of older people. Some gerontologists have a medical degree and are also geriatricians. Geriatrics is the branch of medicine that specializes in the care of older people, which often involves managing many disorders and problems at the same time.

Geriatricians have studied the aging process so that they can better distinguish which changes result from aging itself and which indicate a disorder. The average life expectancy of Americans has been increasing dramatically over the past century.

A male child born in could expect to live only 46 years, and a female child, 48 years. Today, however, a male child can expect to live more than 76 years, and a female child, 81 years. Although much of this gain can be attributed to the significant decrease in childhood mortality, life expectancy at every age beyond 40 has also increased dramatically.

For example, a year-old man can now expect to live to about age 83, and a year-old woman, to about age Overall, women live about 5 years longer than men. Despite the increase in average life expectancy, the maximum life span—the oldest age to which people can live—has changed little since records have been kept. Despite the best genetic makeup and healthiest lifestyle, the chance of living to be is tiny. Madame Jeanne Calment had the longest documented lifespan: years to Heredity: Heredity influences whether a person will develop a disorder.

For example, a person who inherits genes that increase the risk of developing high cholesterol levels is likely to have a shorter life.

A person who inherits genes that protect against coronary artery disease and cancer is likely to have a longer life. There is good evidence that living to a very old age—to or older—runs in families. Get A Copy.

Hardcover , pages. More Details Original Title. Friend Reviews. To see what your friends thought of this book, please sign up. To ask other readers questions about Merck Manual of Health and Aging , please sign up.

Be the first to ask a question about Merck Manual of Health and Aging. Lists with This Book. This book is not yet featured on Listopia. Add this book to your favorite list ». Community Reviews. Showing Average rating 4. Rating details. All Languages. More filters. Sort order. Kathy rated it liked it Jan 29, Dave Beeman rated it it was ok Jan 12, Heinertx rated it liked it Jun 05, Sue rated it it was amazing Apr 10, PD rated it it was amazing Jul 13, Sarah C.

Frazer rated it it was amazing Oct 23, Michael McConnell rated it really liked it Dec 12, Kenneth K. Afton rated it liked it Dec 28, Kat Rich rated it it was amazing Jun 01, Mary Ann rated it it was amazing Nov 01, Mohammed Alsaeiaf rated it liked it Nov 29, Ronald A.

Wiltse rated it it was amazing Dec 21, Travis rated it really liked it Jan 21, Charlotte rated it it was amazing Jan 02, Joe Delaney rated it it was amazing Dec 26, Victoria Risener rated it really liked it Mar 03, Amin marked it as to-read Aug 14, Mark marked it as to-read Mar 14,