Old age

The last stage of human life is old age. It is basically an age when the body starts withering at a fast pace due to slowing of the process of renewal/ regeneration of body tissues. There is no precise age for the old age to start and it varies from individual to individual with respect to his/her genetics, habitat etc. but generally speaking it may be regarded as starting from 50 onwards.   

Theories of ageing
Research done on human cells, indicates that in completely sterile conditions, human cells can survive for almost 120 years. This is known as the Cellular Theory of Ageing, which indicates that human cells have a fixed lifespan, which slowly diminishes in capacity over time.

The Genetic or Heredity Theory of Ageing suggests that our genetics decides our longevity and that ageing and lifespan depend on family genes; in other words, we live somewhat as long as our parents. A simple formula to help you ascertain your approximate lifespan would be to add the ages of your deceased grandparents and parents, and then, divide it by the number of deceased members. However, there are several weaknesses in this system. First, it presupposes that mortality or death will be due to old age, but very often, death could be premature and due to injury or an epidemic. Further, more often than not, the calculation is inaccurate due to the lack of details pertaining to grandparents and ancestry.

The current theory on ageing is the Wear and Tear Theory or the Lifestyle Theory. According to this theory, we will live longer if we adhere to a good healthy lifestyle, and body abuse, irrespective of genes, will result in a relatively earlier demise.
In order to calculate the probable age of demise by this theory, we must begin with the genetic age. If for any reason, you are unable to determine this age because your grandparents are still alive, the next best option is the national average. From this (genetic age or national average), you add or minus one year depending on the impact of negative or positive lifestyle factors that are relevant to you. For example, if you exercise daily, you can add one year, but if you do not, you should minus one year.  

Types of age
Age according to your date of birth is referred to as your chronological or legal age. Age according to your body condition is known as Biological age. We know of many 60 year olds who are fit and active, and many 40 year olds, who are less fit and capable than their 60 year old counterparts. Medical ailments such as heart attacks, cancer, arthritis, etc. are all largely age related.

Young individuals who have these and other such degenerative ailments are referred to as being in a state of accelerated ageing. Thus, a 60-year-old person could be equal to a 40-year-old person and vice-versa. Then, there is also the psychological age, which is largely a matter of attitude. We see many young people who are old-fashioned, regimented, and orthodox; on the other hand, there are many older people who behave younger than their equivalently-aged counterparts, for example a 60-year–old person, who is socially active, mixes with younger age groups, has a job, and so on.  

Effects of ageing
Each of our body cells, whether skin, muscle, or bone, reduces in efficiency as we age. Some, such as skin, hair, nails, blood, etc., survive only for days and weeks but are immediately replaced. However, with each replacement post puberty, the cell efficiency reduces. Other cells, such as in muscles, bones, and the brain, last a lifetime; these deteriorate and are replaced slowly. In general, we may say that post puberty, i.e., (after the age 20) the body reduces its capability and capacity by 1% every year.

Effects of Ageing @1% less per year (post the age of 20) Loss of memory Reduced taste and smell Reduced hearing and vision Reduced cardiac capability Reduced lung capacity Reduced strength, flexibility, and speed Reduced metabolism Reduced sexual libido Loss of hair and skin elasticity

Successful agers

The first study on successful agers (above 90 years of age) was initiated by Cambridge University in the year 1900; this was followed by several other studies including the Baltimore study of 1958, the UCLA study of 1965, and the Alexander Leaf study of 1975. The Alexander Leaf Centenarian’s study in Russia found that the average age was 103 years, BP was 120/80 without medication, pulse 74bpm, most did not need spectacles for reading, and most lived in a cool climate (2°F–15°F). Other characteristics of the successful agers included:  

• An easy going personality
• Married, with family and friends
• Moderate and frugal eating habits, mostly vegetarians
• Physically active, mostly farmers
• Walked at least 5 kms a day
• Never hurried and hated deadlines
• Spent most of the time outdoors in fresh air and cool climate
• Got 8 hours of sleep, rest, and relaxation
• Were sexually active and maintained good hygiene
• Consumed no alcohol and stimulants or tobacco

Increased longevity

The UCLA study quantified the impact of a good or bad lifestyle on longevity in the following manner. According to the study, physical activity benefited the lifespan by adding 10 years to it; whereas obesity reduced lifespan by a similar period. Sleep and relaxation added 8 years to a lifespan; however, stress negatively impacted longevity by 5 years. The Baltimore study, on the other hand, indicated that a good or bad lifestyle impacts genetics and increases or decreases the lifespan by over 32 years cumulatively, beyond the genetic calculation.

 

Factors for increasing longevity by over 13.5 years (In order of importance)
Male	Female
Financial Security	Marriage
Physical Activity	Physical Activity
Mental Occupation	Mental Occupation
Marital Status	Hygiene and Diet
Hygiene and Diet	Financial Security

 

Lifestyle Longevity Predictors
Take daily medication		If yes minus, if no plus
Exercise daily		If yes plus, if no minus
Have job satisfaction		If yes plus, if no minus
Are highly stressed		If yes minus, if no plus
Are competitive, result oriented, and time pressured		If yes to any minus, if no to all plus
Have dependable and good friends		If yes plus, if no minus
Are currently married		If yes plus, if no (incl. divorcee, widowed) plus
Are currently sexually active		If yes plus, if no minus
Are overweight		If yes minus, if no plus
Are currently vegetarian (i.e., no meat, eggs, etc.)		If yes plus, if no minus
Live in a cold climate		If yes plus, if no minus
Get 7/8 hours daily sleep		If yes plus, if less minus
Consume moderate alcohol about once a week		If more minus, if occasionally plus, if never no point
Indulge in smoking and narcotics		If yes minus, if no plus
Are health and safety conscious		If yes plus, if no minus

 So what then is the advice for lifelong health, wealth, and happiness?

Cultivate a circle of dependable friends. Get married. It would seem that any marriage is better than no marriage for a longer life. Do well to others, either individually or as part of a social group. Have faith, either in God, a religious system, or any other belief. Occupation, career, and money are important, not only for a long life but also for the quality of life. Stop comparing and competing. Acquire what you need for yourself and do not envy another persons success or goods. Strive to be without desire and ego. Age gracefully. Do not despair with ageing; each decade has it own joys and benefits. Love and maintain your body, the way you maintain any prized thing.