What Is Biological Age And How Is It Measured?

How do we understand when old age comes? When does the age approach seventy, or when does “the pressure wretched and the heart ache”?

There is no one way people age, which means it is only possible to determine when aging will take place, only very roughly. After all, an eighty-year-old person will run a half marathon, and a fifty-year-old person will not be able to conquer a few flights of stairs.

Why this happens is not known exactly. Many factors influence the rate of aging: lifestyle, genetics, and chronic diseases.

In order to somehow measure it, scientists introduced the concept of biological age. In the article we understand what it is and whether it can be slowed down.

What is biological age — scientific term or fiction?

In scientific articles, two concepts can be found: chronological and biological age. If everything is more or less clear with the chronological age: it reflects the number of years since birth. Biological is a little more difficult.

Scientists have not yet given an exact definition of it, but if we summarize their assumptions, it turns out that biological age  is an indicator that reflects the degree of deterioration of the body.

But how do you rate wear and tear? After all, organs age differently and there can be a lot of parameters: clarity of vision, joint mobility, metabolic rate, and cognitive functions. And each of them has different readings for different people.

Someone has vision problems, but he will run 10 km a day and feel better, while someone has joint pain and it is difficult for him to move, but he sees perfectly.

How to measure biological age

There is no generally accepted method of calculation yet. Scientists are still choosing appropriate methods and formulas, and they are also continuing to search for common indicators or so-called biomarkers of aging in order to assess a person’s biological age and understand exactly how the body is aging from within.

These signs can be indicators of appearance, endurance, weight gain, visual and hearing acuity, the condition of blood vessels and the heart, cholesterol levels, and changes in other blood parameters.

For example, scientists from the Nizhny Novgorod National Research University. NI Lobachevsky has launched an online calculator that analyzes chronological age and blood indicators to determine biological age.

It is not known how accurate the result is, but it might be interesting to see changes in the dynamics.

Some medical services offer to calculate your “real age” by answering questions about your health and lifestyle in a questionnaire.

But such approaches are unlikely to accurately predict potential age-related changes. A much more promising study is the study of the mechanisms of cell aging.

Biomarkers of aging

The attention of many scientists studying the mechanisms of aging is drawn to   nine such indicators:

1) Telomere shortening

Telomeres are the sites that protect the ends of chromosomes from damage and fusion with neighboring chromosomes.

Scientists have found that the older a person is, the shorter the telomeres.

With each new cycle of cell division, telomeres shorten. And when they completely disappear, the limit of divisions (Hayflick limit) is set, and the self-destruction mechanism is launched in the cell. She is getting old and dying.

By the age of 80, telomeres are half their length.

Studies show that people with shorter telomeres have an increased risk of cancer and cardiovascular disease, as well as an early death.

2) Violation of the protein

Proteostasis is the intracellular balance of proteins.

For proteins to function properly, they must have a certain structure and be folded together in the right way.

If for some reason the structure of the protein changes, they will no longer be able to connect with each other and perform the necessary functions. This can cause further damage to cells and disease progression.

3) Epigenetic changes

Epigenetic changes are changes that occur under the influence of external factors and can turn certain genes on or off.

Throughout life, cells undergo a variety of epigenetic changes. The most studied of these are DNA methylation, chromatin remodeling, and histone modification.

It is known that aging is accompanied by the accumulation of epigenetic changes. As a result, the life cycle of cells may decrease or various diseases may develop.

Epigenetic changes, unlike genetic changes, are reversible. That is why scientists are studying it in search of a way to combat age-related changes.

4) Change in nutrient sensitivity

Cells normally know how much nutrients they need and when they need them, just as they know when to grow, divide or die.

But during life, the by-products of metabolism accumulate in the cells, as a result of which the intracellular regulatory mechanisms break down.

Because of this, cells can more actively signal that they lack nutrients. Although in reality it is not.

It is known that such activation of signaling pathways is associated with aging of certain cells and tissues.

5) Mitochondrial dysfunction

Each cell contains structural elements that provide it with energy — mitochondria. During life, the efficiency of mitochondria decreases, and cells accumulate by-products of mitochondrial activity — reactive oxygen species or so-called free radicals.

Free radicals damage healthy cells, speeding up their death, thus bringing aging closer.

6) Cell aging

A senescent cell is a cell in which the limit of divisions is approaching. Normally, a cell that can no longer divide must initiate a self-destruct mechanism. But this is not always the case, as over time the body increasingly “misses” aging cells and they accumulate.

In addition, aging cells release free radicals and signal inflammation. Therefore, its accumulation negatively affects all cells of the body.

7) Low stock of stem cells

Stem cells are immature cells that have not yet “learned” to be, for example, blood cells or brain cells. But if necessary, they replace dead cells. Thus, they provide renewal.

The largest source of stem cells in newborns, with age, the number of cells decreases.

When the supply of stem cells is depleted, the cells age and die, and no new cells can take their place.

8) Violation of signal transmission between cells

Normally, cells are constantly communicating with each other. If an injury occurs in one place or inflammation begins, they send a signal to the brain so that it sends a “rescue team” to the place of damage.

Once the signal is received, the cells stop telling others that something is wrong with them.

In senescent cells, this mechanism may not work and stop giving SOS signals after the ‘incident’ is over.

9) genome instability

Genetic errors constantly accumulate in the body, which are usually eliminated by a special repair system. With age, this system often does not work and errors accumulate. The most common consequence of the accumulation of genetic mutations is malignancy.

How do genes affect aging?

Genes can regulate the cell cycle, which means they can slow down or increase the rate of cell aging.

Scientists have already identified several candidate genes that can influence the rate of aging:

  • Insulin-like growth factor (IGF-1)

People with a long life have an increased sensitivity to insulin while maintaining a lower level in the blood plasma. Certain mutations in IGF-1 extend the lifespan of laboratory mice and flies . 

  • Fat metabolism genes

With age, fat metabolism slows down, which leads to the development of metabolic syndrome and atherosclerosis.

Lipid imbalance is associated with altered activity of several genes.

Hormones regulating fat metabolism play an important role in fat imbalance and longevity: adiponectin, leptin, ghrelin. And their work is controlled by certain genes.  

  • Genes regulating cell senescence and apoptosis (p53, p21, p16, pRB)

These genes are involved in preventing cancer , regulating the cell cycle, and killing unnecessary or harmful cells.

Can aging be stopped?

To date, there are no proven ways to stop or reverse aging at the molecular and cellular level.

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But there are things you can do to improve your overall health now, and in turn slow down biological aging.

Recommendations, most likely, will not surprise anyone. But that doesn’t mean they don’t work:

  • Get enough sleep

To stay healthy and reduce body stress, you need to sleep at least 7-8 hours a day.

  • Balanced eating

The diet should include different food groups: fruits, vegetables, whole grains, meat and fish. So you get all the necessary nutrients and energy supply.

  • Quitting cigarettes and trying to reduce the amount of alcohol you drink
  • Be physically active

Try to devote 30-40 minutes a day to training. It doesn’t matter what it will be: running, swimming, brisk walking or active games with children. Choose what you like and strengthen your muscles.

Learn to Manage Stress Constant stress can be a powerful health destroyer. Try to understand its causes and your reaction, and learn soothing breathing techniques. Youth depends largely on how you learn to relax.

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