Of the 6 billion people in the world, only approximately 25 people are more than 110 years old. Mme Jeanne Calmet of France was one such person. She lived to be 122 years old. She is thought to have lived longer than any other person in recorded history. Mme Calmet took fencing lessons at 85 and rode her bicycle until she was 100. Her life was far from over at retirement4.

In 2000, the number of people over 65 years of age was 420 million people. By the year 2030, this number will be 973 million³. Contrary to popular belief, the greatest percentage (61%) of older people live in developing countries and this trend will increase within the next 30 years to 71%^{3 8}.

What factors allow people to live so long? Is it genetics, environment, or lifestyle that determines our longevity? These questions are studied by scientists known as Gerontologists.

First and foremost, aging is not a disease. However many diseases are age related. Research looks at both aging and age related disease such as heart disease, cancer, and Alzheimer’s⁴. The maximum number of years a human can live is thought to be 125 years. However, life expectance in year 1900 of people in developed countries was approximately 49 years of age. In 1997, this level was 76 years². Better medical care, discovery and use of antibiotics, and greater sanitation have greatly contributed to the dramatic rise in life expectancy⁴.

Aging is the sum of changes that occur in the body over time. Gerontologists use the term senescence to describe the aging process. Some noticeable changes with aging such as greying hair and wrinkles are harmless. However other changes with aging include the deterioration of many of the body’s functions such as the decrease in fertility and the loss of elasticity of the lungs⁴.

Many ideas of why aging occurs have been developed. Some consider aging a “programmed” process that is possibly due to the switching off and on of genes. Programming could also be accomplished through a “biological clock” controlled by the body’s hormones, or possibly a decline in the immune system resulting in an increase susceptibility to disease. The idea that aging is an “error” process has many possible scenarios. Cells of the body may just wear out. Another idea is that animals that more quickly carry out their bodily process (i.e. respiration, digestion, circulation, etc.) may have a shorter life span. Other ideas are that proteins of the body may join each other in ways that damage tissues. Alternatively free radicles may cause accumulative damage of the body, or possibly genes that reproduce over and over again may make mistakes that cannot be repaired. All these ideas have some merit, but examples of exceptions for each idea exist. Picking one as the true cause of the aging process is difficult. Aging most likely is a complex multifaceted process⁴.

In order to further understand the aging process, scientists study fruit flies, yeast, mice, worms, primates, and other creatures. Many generations of fruit flies can be studied compared to one generation of humans.

Genetics does play a role in aging. For example, siblings of centenarians (people over 100 years of age) have a 4 times greater chance of living into their ninety’s than the general population. Current thinking suggests that genetics accounts for 35% of the complex process of aging. Furthermore, research on twins has indicated that environment also plays a role. Remember the saying “You are as young as you feel”? There may be some truth to this.

Gerontologists have found that age in years does not necessarily correspond to your body’s physical age. People age at different rates and so do the organs within a person age at different speeds. Table 1 gives examples on how different parts of the body age⁴.

Table 1: Generalities with respect to normal aging ^{4 5 7}

	Normal aging	Aid to longevity
Sight	40’s difficulty focusing. 70’s possible decline in ability to differentiate fine details.
Hearing	With increasing age, difficulty to hear higher frequencies	Protect ears from damaging decibels throughout life.
Body fat	Late in life weight declines, losing both muscle and fat.
Muscles	Muscle mass declines.	Exercise slows the rate of muscle loss.
Bones	Loss of bone mineral.	Regular weight bearing exercise slows bone loss. Proper diet contributes to increased bone density.
Brain	Nerve cells shrink, increase damage by free radicles. Modest decline in memory and ability to learn occur. Improved vocabulary and verbal knowledge.	Increase use of the brain to think, remember and perceive, results in a reduce decline in memory and the ability to think.
Personality	Relatively stable throughout life. Life altering circumstances may cause changes in personality.	Exercise improves mood.
Heart	Heart muscle thickens.	Exercise reduces risk of heart attack.
Arteries	Stiffen.
Kidney	Less efficient at removing wastes.
Bladder	Bladder capacity declines. Possible involuntary passage of urine.	Certain exercise and behaviour techniques can help manage involuntary urine passage.
Lungs	Maximum breathing capacity may decline.

Aging is inevitable, but that does not mean a person can not be healthy and productive. A commonly held belief is that older people are a burden on society and contribute little. This is far from true. In developing countries, many older people work in the agricultural sector until late in life. Older people also contribute to society through providing care for children or other elderly. Over three million Americans over 65 work as volunteers in schools, health and political organizations, and religious institutions. Many senior executives give their expertise freely to help the less fortunate. All these seniors are making an important contribution to society⁸.

Healthy people in their 70’s and 80’s can perform just as well on complex tasks of learning and memory given sufficient time⁷. Studies have also indicated that when the elderly are given tasks that engage their emotional interest, their ability to perform memory tests is equal to that of younger people⁶.

Many factors influence the way a person ages, and a number of these factors are within that person’s control. Lifestyle effects aging. A properly balanced diet will help prevent the chronic disease associated with aging. Lung cancer and heart disease are not natural to aging, but can be prevented by a proper lifestyle such as exercise, proper nutrition, and no smoking. Research has also found that when mice were fed a nutritionally balanced meal with 30% fewer calories, they lived 40% longer. This idea is now being tested on monkeys but is some time off before inferences can be made to humans⁴.

Exercise is vital at any age, and the elderly are no exception. Research has indicated that, muscle mass can be developed even in older individuals. For example, on a 10 week exercise program, a number of 80 years olds were able to progress from using walkers to canes⁴.

Healthy aging is a responsibility of each individual person. A person needs to maintain a proper vaccination program and ensure screening for possible problems such as breast and colon cancer are done at the appropriate age. Regular medical and dental checks up are also part of a healthy living plan. Exercise to strengthen muscles, improve flexibility, and balance will help prevent falls⁸. Elimination of potential hazards that could cause a fall is also important. Of those who experience a fall and subsequent fracture, 25% will pass away within one year of the incident. Therefore, fall prevention is very important¹.

A healthy long life is influenced by many factors. Many factors such as lifestyle and attitude are with control of each of us. At Mme. Calmet’s120^th birthday party, a journalist was reported to say “Well, I guess I will see you next year”. To which Mme Calmet responded promptly, “I don’t see why not. You look to be in pretty good health to me!”⁴ With a great attitude like that, why not live long and be prosperous?

References: Aging: Better with Time

1. CDC. 2003. Healthy Aging. Preventing Disease and Improving Quality of Life among older Americans. www.cdc.gov/aging
2. Hayflick, L. 2000. The future of ageing. Nature 408: 267 – 269
3. MMWR. 2003. Public Health and Aging: Trends in Aging---United States and Worldwide. CDC 52(6):101-106. www.cdc.gov/mmwr/preview/mmwrhtml.mm5206a2.htm
4. NIA. Aging under the Microscope A Biological Quest National Institute of Health, National Institute of Aging, NIH publication No. 02 – 2756
5. NIA. 2003. Alzheimer’s Disease Progress Report 2001 – 2002. National Institute of Aging. National Institutes of Health NIH Publication#:03 – 5333
6. Rahhal, T. A., Hasher, L, Colcombe, S. J. 2001 Instructional manipulation and age differences in Memory: Now you see then, now you don’t. Psychology and aging 16 (4), 697 – 706
7. Rodger, A. B. 2002. Alzheimer’s Disease unravelling the mystery. National Institute of Aging. National Institute of Health. NIH Publication No – 02 – 3782
8. WHO. Aging Exploding the Myths. World Health Organization. Ageing and Health Programme. WHO/HSC/AHE/99.1

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