Predicting Human Longevity
Factors That Determine Human Longevity
One sure thing is we will all die someday, but almost none of us know when that will happen unless we are at the end stage of a deadly disease. Scientists try to predict how long individuals will live by evaluating various human characteristics. Obviously, we all have a genetic influence on the quality and length of our lives. The other considerations may be the way we live. This includes, among other things, what we eat, body weight, exercise and the way we handle stress.
The goal of longevity is the striving for our maximum potential age. Women have greater longevity than men.
Appendicular Muscle Mass
The appendicular lean muscle mass (ALM) is being used as a strategy for predicting longevity in people over the age of 65 years. There is a growing concern about age-related muscle loss in an aging society. Age-related loss of muscle mass and strength is termed ‘sarcopenia’, which is the degenerative loss of skeletal muscle mass (0.5–1% loss per year after the age of 50), quality, and strength associated with aging.
The study by the National Institute for Longevity Sciences - Longitudinal Study of Aging, Japan evaluated 1026 men and 952 women between 40 and 79 years old. The researchers estimated hazard ratios for mortality or disability for men and women. To adjust indices, they did measurements for:
- ALM/leg length
- ALM/body mass index (BMI)
They concluded that an unadjusted baseline was more appropriate to predict longevity and disability, particularly in women.
The University of Sao Paulo’s Medical School in Brazil evaluated 839 men and women over the age of 65 for four years. The appendicular muscles in the arms and legs are very important in stabilizing the shoulders and hips. Individuals with a muscle mass below average by 20% were classified as having sarcopenia.
The body composition was evaluated by dual-energy X-ray absorptiometry, which determines the bone density. It was determined loss of ALM increased morbidity and mortality, but they did not have exact percentages that could predict longevity.
Muscle Loss and Aging
Calorie intake has generated numerous recent studies. Typically, sarcopenia associated with osteoporosis increases the vulnerability of senior citizens. They become prone to fractures, falls and other physical injuries. Low bone density, particularly in the femur (bone in the lower leg), is correlated with mortality in the elderly.
Human beings that are known for longevity were studied to compare calorie intake with an extended lifespan and the lower likelihood of disease. The restriction of calories reduced excess body weight and belly fat, which are both associated with a shortened lifespan. It is not understood at this point as long-term calorie restriction may be unsustainable due to lower body temperature, increased hunger, and a diminished sex drive.
The Division of Geriatrics and Nutritional Science and Center for Human Nutrition states calorie restriction (CR) does play an important role in many of the age-related chronic illnesses associated with aging. Human studies indicate that adequate nutrients in the diet resulted in many metabolic adaptations, which reduce the development of type 2 diabetes, cardiovascular disease, hypertension, and cancer. Additionally, CR inhibits the typical age-related alterations in autonomic function, myocardial stiffness and gene expression in the skeletal muscles. This could be due to a high-quality diet rather than calorie reduction.
One-third of people over 65 are obese, so a healthy diet will obviously help prevent disease, and you will probably feel better overall. For obese people, calorie restriction is a healthy choice, and it may just be that healthy food choices will help lose those extra pounds. A heart-healthy diet of 1,800 calories with enough calcium for bones and proteins for the muscles is considered important for senior adults.
Numerous significant improvements in water, availability of food, improved housing and living conditions, and limited exposure to infectious diseases began in the 1900s. In addition, advances in public health have reduced infant mortality and increased the chance of survival in childhood. Communicable and infectious diseases are less common as well.
The study of people in their nineties, centenarians and semi-centenarians (ages 105-109) have been studied for commonalities. As for education, profession or lifestyle, they have little in common. Their shared similarities include being non-smokers, having a normal body weight, and they cope with problems without much stress. Most of them were women. Their children and their siblings are more likely to remain healthy and live to old age as well. They are less likely to have typical age-related, chronic diseases that are common among their peers.
A long life is a life well spent.
--Leonardo da Vinci
Currently, scientists have determined that approximately 25% of the human lifespan is determined by genetics. They do not fully understand which genes affect longevity. Whole-genome sequencing has identified increased disease risk and some genes that possibility promote longevity. There is still much to learn about genetics
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Psychological Factors Affecting Longevity
Biomedical research on the hypothalamus indicates this area of the brain exerts fundamental control over aging. An individual’s resilience can be measured by their education, hobbies involving mental and physical exercise, spoken foreign languages, extended family and social networking.
The purpose in life and reason for getting up each day is relevant. Lessons have been learned from geriatric psychology, which has been under-represented as a health discipline in the past for mortality modeling.
Lifestyle to Improve Longevity
There are several things you can do to improve longevity in your life, such as:
- Do not smoke
- Moderate exercise on a regular basis
- Adequate sleep includes 7-9 hours nightly
- Eat plenty of vegetables and healthy proteins
- Maintain a healthy weight
- Do not drink alcohol, or at least on a very limited basis
- Enjoy mental activities daily by challenging yourself
- Manage stress carefully by developing healthy coping skills
- Cultivate personal relationships with family and friends
- See a dentist regularly, floss and brush
- Be sure to get adequate calcium and vitamin D
- Follow preventive care guidelines
Most people want to live a long healthy life. Ideally, begin healthy habits early in life, but if you did not do that, the choice can be made anytime. Changing your habits later in life can still be beneficial and extend your longevity. It is clear that the oldest people in the world have almost always lived a life with healthy food, exercise, and they keep a normal weight.
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2019 Pamela Oglesby