Whether we easily reveal our chronological age to others or keep it close to our chests, we can’t deny time. We’re stuck with what we’ve got and it steadily increases year after year. If you are chronologically 34 years old today, you’ll be 35 years old next year. That will probably be true for the rest of your life, unless you find a way to freeze time (or cryopreserve yourself!).

But what if you could change your age? What if by fasting, eating healthy and exercising, for example, you could change how old you are?

Jump down in this post to calculate a metric of your biological aging here.

“Even to the untrained eye it has always been apparent that different people age differently.” – Jazwinski & Kim, 2019

Welcome to the concept of biological age. Your biological age is a measure of how the biological aging progress has impacted your body. It can be defined in terms of what researchers call frailty indices – in what areas does your body work less well today than it did last year, or a decade ago? Do you have a shorter working memory? Are you less insulin sensitive? Do you have a lower lung capacity?

What is exciting is that unlike your chronological age, which you can’t do much about except to accept get older and wiser, you can change your biological age with the health-related decisions you make in your daily life. What’s more, researchers are finding that your biological age relative to your chronological age is a better indicator of your healthspan, or the estimated length of your highly functional and disease-free life. That’s good news for most of us, because most people would rather live healthier than live longer.

But your biological age can also help predict your longevity. It turns out that your chronological age, or how old you are based on the passage of time, is a poor indicator of your health and even, past a certain age, a poor indicator of survival or mortality. This is true especially as you approach a century of life. The idea that you are “one year closer to death” becomes less and less true as you age, particularly with each birthday you have after you hit 90. The relationship between your chronological age and your mortality even plateaus as you hit your 100’s. At 100 years old, your risk of dying is nearly the same as at 101, 105 or even 110!

After you hit 90, it is your biological age, or the toll that the biological aging process has taken on your body in particular, that is a much better predictor of your health and mortality. At 90, you might “look” like you are 80 in terms of how your body functions… or you might look like you are 110. The same is true throughout your life. You could be 50 but look (both on the inside and outside of your body) like you are 42… or 63.

“Any measure of biological age must be better than chronological age at predicting mortality.” – Jazwinski & Kim, 2017

Aging may be inevitable – but what happens to your body and mood as you age is partly up to you. Photo by Huyen Nguyen on Unsplash.

What Really Happens As We Age?

There are many unwanted changes that we associate with getting older. When we think of aging, we might think of reduced functional ability – most 70 year olds we know aren’t climbing mountains or running sprints, and the ones who are intrigue us in viral Youtube and social media videos because of their rarity. We might think of less effective cognitive function – forgetfulness and slow learning. (Although hint: We may be able to maintain or even increase cognitive function as we age, thanks to our very “plastic” brain, if we engage in healthy aging behaviors like learning something new every day, exercising and meditating.)

Diseases as varied as macular degeneration, type 2 diabetes, heart disease, cancer, pulmonary disease, Alzheimer’s disease, osteoporosis and arthritis have come to be known as diseases of aging. This is because the primary risk factor for developing these diseases is aging itself. But these diseases likely have a stronger association with the biological process of aging than with the chronological, passage-of-time one.

“What has become clear over the past decade or so is that the contributors to these disorders at the cellular level are damaged molecules and organelles,” S. Michal Jazwinski, John W. Deming and MD Regents Chair in Aging at Tulane University, and Sangkyu Kim write in a 2017 paper investigating markers of biological aging. Jazwinski and Kim recently outlined a new way to model biological aging as the disintegration of a complex network of interconnected systems and functions in the human body (more on that later!). As we age, the molecules and structural components within our cells (their organelles or tiny “organs” such as the energy-producing mitochondria) become damaged by stress, overuse, exposure to sunlight and other radiation, toxins and even by byproducts of our metabolism.

But how does damage to tiny pieces within some of the trillions of cells that make up our bodies add up to diseases of aging as complicated cancer or dementia?

The answer brings to mind the age-old adage attributed to Aristotle that “the whole is greater than the sum of its parts.” Jazwinski and Kim have found that we can model the biological aging process as a system, a complex and dynamic network of interconnected factors. These factors are reflective of the interconnected components that make up our body, with the connections being blood vessels, hormones and other signals that allow cells, tissues and organs to communicate with one another.

This biological age network looks like a spiderweb that changes shape every night as old strands are broken by flying insects and new ones are formed by the spider’s spinnerets. As long as the spiderweb keeps enough of its interconnecting strands intact, it will retain its shape and function as an effective trap for insects. But if too many of its spiral strands break, or if even just a few of the more vital radial threads break, the web may no longer be effective at catching anything and will eventually collapse.

Aging is like a complex network slowly unraveling. Photo by Clarisse Croset on Unsplash.
Aging is like a complex network slowly unraveling. Photo by Clarisse Croset on Unsplash.

The aging system is the same. The loss of too many of its components, or the signaling pathways that connect them into a network, leads to a less complex, less functional system. This happens as your biological age increases. The greater your biological age, the worse the different components of your body communicate and work together. Your body also ends up spending more and more energy trying to keep this broken and dysfunctional  system running.

The concept that biological aging is like a complex system losing its interconnections, shape and complexity, like a broken spider web or dysfunctional engine, is also reflected in our genes. For example, researchers have found that increased age is associated with DNA methylation that causes silencing of a protocadherin gene. Protocadherins are cell adhesion proteins that help cells communicate and interact with one another, as individual components of a larger tissue or organ network.

“At all levels, there is a decline in connectivity and functionality with age, rendering the organism less robust and resilient.” – Jazwinski & Kim, 2017

Unexpected Changes

We’ve been looking for markers and predictors of aging in all the wrong places, by searching for aspects of our function that increase or decrease with chronological age. Researchers are now finding unexpected changes that follow increased biological age. We’ve missed these true aging characteristics by assuming that all 60 year olds should look something alike, ditto for 80 year olds, 90 year olds, etc.

For example, we have known for some time (or thought we’ve known) that individuals’ energy metabolism declines with age.

“You sort of expect that – people slow down as they age, right?” said S. Michal Jazwinski. “One component of energy metabolism is called resting metabolic rate; it’s the amount of energy required for maintenance of basic body functions. Sitting in your chair [reading this blog post], even dozing off, you are still using 60 to 70% of your total energy expenditure. Resting metabolic rate also is known to decline with [chronological] age – except that we found [in the Louisiana Healthy Aging study] that resting metabolic rate actually increases with biological age.”

The older you are biologically, or the less healthy, Jazwinski explained, the more energy you use just meeting your basic bodily functions. Expending more energy to keep your body running as you age makes sense if the aging systems in your body (heart, brain, gut, pancreas, etc.) are no longer communicating and functioning well together.

“It takes more energy to keep things running when you’ve lost integrated function,” Jazwinski said.

In other words, as you age you develop deficits in various biological systems throughout your body. These systems normally work together to form a well-oiled machine. Lose the oil and a few important bolts and screws, the network of connected moving parts collapses. Dysfunction in one area also spreads, like dirt in your oil filter can spread to other components of your engine. You’ve lost integrated function.

Jazwinski’s finding that resting metabolic rate increases with biological age in individuals was unexpected based on population-level studies of chronological aging. But the finding is reflective of the new-ish idea that metabolic dysfunction is a key component of biological aging. This dysfunction involves inefficiencies, like an insensitivity to insulin, cellular senescence and damaged proteins, that force our cells and mitochondria to work harder, not smarter.

Jazwinski also found that muscle tissue damage in men, and loss of muscle mass in women, are related to the increased resting metabolic rate of unhealthy, biologically aged individuals. Physical activity (and perhaps even fasting) could help protect aging individuals from this increased resting metabolic rate that brings with it more harmful metabolic byproducts like reactive oxygen species and leaves less energy for higher cognitive and physical functions.

Maintaining muscle mass may be a key component of aging successfully. Photo by Form on Unsplash.
Maintaining muscle mass may be a key component of aging successfully. Photo by Form on Unsplash.

Unexpected changes that occur with biological aging extend to the systems of gut microbes that live in and on us.

Jazwinski and colleagues have found that our gut microbiome, or the system of microbes that live in our gut and help us break down plant fibers for example, loses complexity with biological age. A healthy gut microbiome is one composed of a complex and diverse mix of microbes that display daily rhythms, produce brain-boosting and inflammation-fighting short-chain fatty acids and more. With biological aging, the gut microbiome becomes more uniform, potentially with fewer healthy microbes and a greater proportion of unhealthy or pathogenic ones.   

“The impact of the gut microbiota goes beyond metabolism to influence inflammation and immunity, leading to age-related degenerative disorders associated with unhealthy aging. […] Richness (alpha-diversity) or intra-individual variation in the gut microbiota declines as a function of biological age, while showing little or no difference with chronological age.” – Jazwinski & Kim, 2017

Is there anything we can do to stop the slow breakdown of the aging network that is our body, to fight off metabolic inefficiencies and the loss of our gut microbe diversity? Remember that age isn’t the primary driving force behind this breakdown. The breakdown happens over time as we accumulate “deficits” in seemingly isolated parts of our body – some anxiety here, some high blood sugar there, a seemingly unrelated inflammatory disorder. But these deficits, drumroll, often respond to our environment and lifestyle!

(P.S. – those deficits are all in the end interconnected.)

How Old Are You, Really?

Satchel Paige, the famous American Negro league baseball and Major League Baseball pitcher, cultivated a mystery around his age (he claimed not to know the date of his birth) but played well into his 50’s. When asked about his athletic longevity, he once answered with this brilliant question: “How old would you be if you didn’t know how old you were?”

To determine how old you really are, you need to know how well various components of your body are working. You also need to know how well they are working together. If one component of your aging network becomes dysfunctional, it brings other components down with it. For example, a poor diet, obesity and lack of physical activity can lead to insulin resistance and diabetes. Over time, unmanaged high levels of blood glucose and insulin associated with diabetes will cause breakdown in other systems of the body, including the cardiovascular system, nerves and brain.

Jazwinski has developed a new and robust way to estimate biological aging based on a “frailty index” that accounts for the health status of various biological components and systems throughout your body, from your blood to your muscles to your brain. This biological aging estimation or frailty index, called FI34, uses 34 measures of physiological, biological and mental health deficits that when summed reflect a person’s overall aging status. The higher your FI34 score, the more health-related deficits you have that impair your health and ability the function.

FI34 predicts age-related disease and mortality better than chronological age does. Based on a study of several hundred individuals 60 years old and older in Louisiana, there is a 27% increase in the hazard of death every time an individual’s FI34 score, which ranges from 0 to 1, increases by 0.1. Each additional year of chronological life, by comparison, only increases the hazard of death by 1.7%.

“FI34 is a measure of healthy aging, as lower values of this metric represent fewer health and function deficits.” – Jazwinski & Kim, 2017

The 34 health deficit measures that go into estimating biological age according to FI34 all fall under overarching health and disease categories that you are probably already familiar with. They include things like inflammation, mental health, weight, physical fitness, cardiovascular fitness, lipid levels and metabolic health. FI34 takes into account genetic factors as well as environmental factors of health and disease, meaning that it is partly heritable. If your parents live long lives, you are likely to have delayed onset of age-related disease and disability – as long as you treat yourself well. On the other hand if your parents age quickly, you are more likely to as well.

The good news is that you can still modify your environmental and lifestyle factors to compensate for aging factors that you may have inherited from your parents. For example, fasting, mindful activity and a plant-heavy diet can help reduce stress and inflammation. Fasting and exercise can help you reach and maintain a healthy weight. Fasting, vegetable and fruit consumption, exercise and adequate sleep can help preserve your insulin sensitivity and metabolic health.

A Measure of Biological Aging

The following are some common questions used to measure FI34 and other estimates of biological age. You can determine your own frailty index score by answering the following 20 questions, summing your results and dividing by the number of questions (n = 20).

  1. Self-rating of health (Excellent = 0, Very good = 0.25, Good = 0.5, Fair =  0.75, Poor = 1)
  2. Body mass index (BMI) (Under 25 = 0; Between 25 and 30 = .5; Over 30 = 1):
  3. You’ve been told that you have diabetes (Yes = 1, No = 0)
  4. A first-degree relative has had cancer (Yes = 1, No = 0)
  5. You have high blood pressure, greater than 99/159 (Yes = 1, No = 0)
  6. You have had high blood pressure before (Yes = 1, No = 0)
  7. You’ve been told that you have high cholesterol (Yes = 1, No = 0)
  8. You’ve been told that you have anemia (Yes = 1, No = 0)
  9. You’ve been told that you have asthma or other lung dysfunction (Yes = 1, No = 0)
  10. You’ve been told that you have COPD (Yes = 1, No = 0)
  11. You can do at least one deep squat (Yes = 0, No = 1)
  12. You’ve been told that you have a heart problem (Yes = 1, No = 0)
  13. You’ve had a heart attack (Yes = 1, No = 0)
  14. Depression scale (Under 6 = 0; Between 6 and 10 = .5; Over 10 = 1):
  15. You’ve been told that you have a kidney disease (Yes = 1, No = 0)
  16. You’ve been told that you have a liver disease (Yes = 1, No = 0)
  17. You’ve been told that you have an adrenal disease (Yes = 1, No = 0)
  18. You’ve been told that you have a thyroid disease (Yes = 1, No = 0)
  19. You’ve been told that you have osteoporosis (Yes = 1, No = 0)
  20. You’ve had a seizure (Yes = 1, No = 0)

You can also compare your score to average scores of people your age. Individuals under the age of 50 typically have a score of under 0.1, while individuals 60 to 90 years old have an average score of around 0.2. With lifestyle inventions, your score can even go down as you age! 

*Note – this modified scale only has 20 factors while the FI34 index has 34 – your score on the scale above might therefore be somewhat inflated. Find and calculate the full index here.

Decrease your biological age and increase your healthspan by moving throughout your life. Photo by George Pagan III on Unsplash.
Decrease your biological age and increase your healthspan by moving throughout your life. Photo by George Pagan III on Unsplash.

Other predictors of biological aging that may be more informative for young people, to determine risk of premature aging, include your cardiorespiratory fitness, your BMI, your fasting blood glucose levels and measures of insulin sensitivity, your lung function, your blood lipid levels, your levels of inflammatory markers such as C-reactive protein, your white blood cell counts and your blood pressure. You can get these things measured with most standard blood and physician physical examination tests – just ask your physician. Most if not all of these factors also respond to your environment and your lifestyle, so following national guidelines for daily exercise, balanced diet, fruit and vegetable intake and sleep, and not smoking, can substantially help you keep your biological age matched to or even under your chronological age.

“[G]enetic and environmental factors affect functional decline with age. For example, decline in learning ability during aging is modulated by the 𝜀4 allele of APOE (Papenberg et al., 2015). This allele also interacts with life events, an environmental factor, to impact negative affect in centenarians (Martin et al., 2014). Individual profiles in age-related changes are also found for physical function, just as they are for cognitive function.”  – Jazwinski & Kim, 2017

Age Successfully

Are you or will you be a successful aging person? Successful aging is marked not by how you look, but by your level of disease and disability, relatively high physical and cognitive functioning and active engagement in life activities.

To age successfully, including tips from the CDC:

LifeOmic’s LIFE Extend app will help you engage in preventative health practices, including health screenings and staying connected with your doctor and other wellness practitioners. Learn more and sign up here.