Chapter – 5
AGING
When the body is shriveled
And another steps falter;
When the teeth are decayed
And the face smeared with slobber,
When sight fails
And the figure is no longer trim;
The Kinsfolk find no time for conversation
Even the son despises the man
Overcome by old age, alas!
– The Panchatantra 200 B.C?
The long habits of living indispose us from dying.
– Thomas Broune, 1643
Ageing (British English) or aging (American) is the accumulation of changes in a person over time. Aging in human refers to a multidimensional process of physical, psychological and social change. Some dimensions of ageing grow and expand overtime, while others decline. Reaction time, for example, may slow with age, while knowledge and wisdom may expand. Age is usually measured chronologically, (time keeping age) and a person’s birthday is often an important event. Time related aging (chronological) may be distinguished from “social aging” (cultural age – expectations of how people should act as they grow older) and “biological aging” (an organism’s physical state as it ages). For example if you are in excellent health and not overweight, if your chronological age is 70, your biological age may be 65 and your heart age may be 60.
Senescence
In biology, the word, senescence means the state or the process of aging. Cellular senescence is a phenomenon where isolated cells show a limited ability to divide in culture. It was discovered by scientist Leonard Hayflick in 1961, and is known as Hayflick Limit. After a period of near perfect renewal (in humans, between 20 and 35 years)., human being face increasing risk of disease. This currently irreversible series of changes inevitably ends in death.
Some scientists claim aging is an avoidable property of life, that it is the result of a genetic program. Numerous species show very slow signs of aging or negligible senescence. Some of them are sturgeon and rock fish, invetebrate (not having a backbone) like the quahog and sea anemone and lobster.
Theories of Aging
At present, the biological basis of aging is unknown. Even in the relatively simple and short-lived organisms, the mechanism of aging is not known. Much less is known about aging in humans. Theories of aging, are numerous and no one theory has been accepted. Regardless of theory, there is no disagreement that people age, and functions of the body decline.
Wear and Tear Theory
Wear and tear theories suggest that as individual ages, body parts such as cells and organs wear out from continued use. Wearing of the body can be due to internal and external causes, surpassing the capacity of the body to repair. Due to many internal and external insults, cells and organs lose their ability to repair and regenerate. Some of these insults include chemicals in the air, sunlight, smoke, free radicals in foods, trauma and bacteria and viruses.
Genetic Theory
Genetic theories of aging propose that aging is programmed within each individual genes. According to this theory, genes dictate cellular longevity. Programmed cell death (known as apoptosis), is determined by a “biological clock” via genetic information in the nucleus of the cell. An increase in cellular death may corrdate with aging, but is not a cause of death. A number of genetically based diseases show accelerated aging. One of them is progeria, a very rare disease. Children with progeria look old and die as young as thirteen years of age. Just one gene is involved.
DNA Damage Theory
DNA damage has been one of many causes in disease related to aging. DNA damage causes cell to stop dividing or induce cell death. DNA damage is thought to be the common pathway causing both cancer and aging.
General Imbalance Theory
General imbalance theories of aging suggest that body systems, such as the endocrine, nervous, and immune system (system that fights infection), gradually decline and ultimately fail to function. The rate of failure varies system to system.
The Free Radical Theory
The free radical theory of aging argues that aging results from the damage generated by reactive oxygen species (ROS). ROS are small, highly reactive, oxygen – containing molecules that are naturally generated in small amounts during the body’s metabolic reactions. ROS cause disease related aging, such as dementia, cancer and heart disease. The Free Radical Theory of Aging is not accepted by everyone.
Social Theories of Aging
According to Dannefer, aging is an interactive process where the individual is affected by the environment. Several theories of aging have been proposed by social scientist.
Activity Theory
Activity theory implies that the more active elderly people are the more likely they are to be satisfied with life. Activity is preferable to inactivity because it helps well-being in multiple levels. The view that elderly adults should maintain well-being but keeping active has a considerable history. Active older adults have less chronic diseases like – diabetes, hypertension, heart disease, stroke, arthritis and dizzy spells.
There are many other social theories of aging like – Disengagement theory, Selective theory, Continuity theory etc, but all of them have their weaknesses and are not based on sound scientific principles.
Healthy Aging
Older people are more likely to have chronic diseases and associated disability. The most frequently reported conditions in elder population are arthritis (48%), hypertension (36%), hearing problem (32%), heart disease (32%), bone and joint disease (19%), cataract (17%) (opacity of lenses), sinusitis (16%), diabetes (11%) and ringing in the ears (9%). Many of these chronic conditions are not life threatening, but have impact on quality of the person’s life.
We all age differently. Genetics, life style, and disease processes affect the rate of aging between and within all individuals. The National Institute on Aging (NIA), part of National Institute of Health (NIH-USA), investigates ways to support healthy aging and present or delay the onset of age-related disease and decline.
Lessons from the Baltimore Longituding Study on Aging (BLSA)
The BLSA study began in 1958 – at National Institute on Aging (NIA) at Baltimore, USA. The study is ongoing. Following are some of the recommendations of NIA (based on BLSA and other studies) for healthy aging.
1 – Get Moving
Exercise and physical activity are the corner stone of healthy aging. People who exercise regularly not only live longer, they live better. And, being physically active – doing everyday activities that keep your body moving, walking, taking the stairs instead of the elevator (Lift), gardening, and doing household works.
Regular exercise and physical activity can reduce the risk of diseases and disabilities that often occur with age. For instance balance exercises help prevent falls and breaking bones. Strength exercises build muscle and reduce the risk of osteoporosis (thinning of the bones) and prevent breakage of the bones. People with high blood pressure, arthritis and diabetes can benefit a great deal from regular exercise. Endurance exercises (-activities that increases your heart rate)
– such as walking, swimming bicycling, and dancing can increase your stamina and improve the health of your lungs and heart. The best is to mix your exercise routine – aerobic, strength, and balancing.
2 – Pay Attention to Weight and Shape
People who are overweight (BMI-Body Mass Index 25 to 29.0) or obese (a BMI greater than 30) are at greater risk for Type 2 diabetes, high blood pressure, heart disease, stroke, some types of cancer, sleep apnea (forgetting breath during sleep), osteoarthritis (the wearing away of joints). But data show that for older people, thinner is not always healthier, either. Older men and women who are thinner (BMI – less than 19) have higher death rate. People with “pear” shape, with fat deposit around the hips and thighs, are generally healthier than people with the “apple” shape, with fat deposit mostly around the waist. Belly fat increase the risk of heart disease. The best is to maintain an ideal body weight and avoid belly fat.
3 – Healthy Food: Think About What You Eat
A diet rich in colored fruits and vegetables, whole grains, low saturated fat, low fat milk products and lean meat and fish is good for all age group. Diet for older people should be:
- Whole enriched and fortified grains and cereals such as brown rice and 100% whole wheat bread.
- Bright colored fruits and vegetables of all kinds.
- Low fat diary products such as yogurt and milk.
- Dry beans and nuts, fish, poultry, egg; and unprocessed lean meet.
- Liquid vegetable oils – avoid butter and saturated fat.
- Low trans fats salt. Two of the best sources for unbiased information on diet are – www.choosemyplate.gov and www.nihseniorhealth.gov
4 – Participate in Activities You Enjoy
According BLSA data and other studies, people who are sociable, generous, and goal-oriented report higher level of happiness and lower levels of depression than other people. Hence stay involved with your friends, family and community.
5 – Get Regular Health Screening
See your physician on regular basis and get some age – appropriate screening tests like – mammography (for defection of breast cancer), colonoscopy (for detection of colon cancer), pap smear (for cervical cancer), rectal examination (for defection of prostate cancer), fasting blood sugar or HbA1 C for the detection of diabetes, and blood pressure check for hypertension. Get yearly flu shot and other vaccines to prevent some diseases. Prevention and early detection of a disease is always better than an expensive cure. Many cancers (colon cancer, breast cancer) if detected early enough can be completely cured.
Can We Prevent Aging?
People are living longer. Views on aging are also changing. Disease and disability were once considered an inevitable part of growing older but that is no longer true. While aging does put us at greater risk for health issues, many older adults can be healthy and active well into their advancing years.
We already know that healthy eating and exercise and physical activity help promote healthy aging. Are there other interventions that can help? National Institute on Aging (NIA-USA) supported and other studies are taking look at the possible benefit and risks of a number of approach including antioxidants, Caloric restriction, and hormone supplements. According NIA, until we have a better understanding it is a good idea to be skeptical of claims that any supplements can solve your age-related problem.
Antioxidants
Antioxidants protect the body from the harmful effects of by-products known as free radicals, made normally when the body changes oxygen into energy. The discovery of antioxidants raised hopes that people could slow aging simply by adding to the diet. So far, studies of the antioxidant-laden foods and supplements in humans have yielded little support for this conclusion. For now, although the effectiveness of dietary antioxidant supplementation remains controversial, there is positive evidence for the health benefits of fruits and vegetables.
Caloric Restriction
Scientists are discovering that what you eat, how frequently, and how much may have an effect on quality and years of life. Of particular interest has been Calorie restriction. Research in some animals has shown Calorie restriction of up to 40 percent fewer calories than normal to have impressive positive effect on disease, markers of aging, and perhaps, life span. Calorie restriction has been found to extend the life span of protozoa (very small one-celled organism), yeast, fruit flies and certain strain of mice and rats. Studies in apes and monkeys have shown conflicting results. Calorie restriction studies with humans and other primates are ongoing. Scientists do not yet know if long term calorie restriction is safe, beneficial, or practical for humans. We have to wait for the final verdict.
Many other potential agents to reverse the aging processes are being studied including human growth hormone; sex hormone like estrogen. So far there is no proof that any of them delay aging.
According to National Institute of Aging – Finding a “fountain of youth” is a captivating story. The truth is that, to date, no research has shown that hormone therapies add years to life or prevent age related frailty-NIA does not recommend taking any supplement touted as “anti-aging” remedy because there is no proof of effectiveness and the health risks of short-term and long-term use are largely unknown.
Until more is known about antioxidants, resveratrol, and hormone supplements, people should view these types of supplements with a good deal of caution and doubt. ….. Some harmful side effects already have been discovered; additional research may uncover others.” (NIA – 1/24/14).
Sources
- Wikipedia.org/Immortality 12/27/2013
- Wikipedia.org/Ageing 12/30/2013
- Wikipedia.org/Gerontology 12/30/2013
- National Institute of Aging, www.nia.nih.gov / aging-longevity 1/1/2014
- National Institute of Aging, www.nia.nih.gov / can-we-prevent aging. 111/2014.
- NIA Senior Health www.nih seniorhealth.gov