Life After Full-time Work Blog

The parts of our body that tell us how much we’ve aged, and what biological age means for you and me. Also, one more You-Tube interview

Quickly, let me start by giving you this link to (another) interview I did with my friend David Toyne at Steadyhand. The Steadyhand website describes it this way: “In this Coffee Break, we welcome back actuary and retirement expert Don Ezra to discuss one of the most important aspects of retirement — how to confidently transition from saving to spending. Drawing from his own experience, Don shares a practical framework he and his wife use to manage their finances, centred around the concept of a ‘personal funded ratio.’ The conversation also explores useful tools such as the Longevity Illustrator, how to think about real estate in your retirement plan, and why many retirees tend to underspend out of fear of running out of money.” It’s about 16 minutes long.

OK, now to this post’s topic: your biological age.

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You’ll remember that recently I wrote about how I wonder whether our lifespan is influenced more by genetics or by lifestyle. And I mentioned the concept of biological age, which is the average chronological age of people who have the same health characteristics as you do. So, for example, you may be 60 years old chronologically, but if your health is more like the health of an average 52-year-old, then your biological age is 52.

We know that our chronological age increases by one day every day, one year every year. It’s simply the passage of time that affects it. But do we know what affects our biological age?

Before we get to that, let’s recognize that we’ll never know exactly what our biological age is. Different parts of our body age at different rates. So, some parts of our body are biologically older than other parts. Does it matter? In a sense, no – because ultimately it’s one thing that’ll take us away, and then it doesn’t matter how old or young other parts of our biological system are (although, of course, the one thing that takes us away may itself be a combination of many parts of our biology).

That suggests that the best we can do is to find some way of combining the different biological ages of many parts of our body, and use that combination as a rough estimate of our overall biological age.

Which suggested these questions to me: what are the relevant parts of our body, and how can we estimate their biological ages and combine them into a single rough overall estimate? So, of course, I did a lot of research online.

In particular, the most useful findings were in a paper called Biological Age Predictors: The Status Quo and Future Trends. It’s (shall we say) more than a little bit technical. Anyway, here’s what I eventually got out of it.

Scientists call the relevant things “biomarkers,” and the paper groups them into three categories:

• Blood markers; and, more importantly, no single blood marker, but certain combinations of blood markers (like albumin, erythrocytes, glucose, urea, cholesterol, and other stuff whose names meant nothing to me).
• Molecular and genetic markers, like sets of RNA (a molecule you may have heard of, that plays a vital role in creating and moving things in our body), blood plasma, T-cell receptors (T-cells are a type of white blood cell).
• Epigenetic markers (molecules and neural networks that seem to run down as we age). Among them you may have heard of telomeres, which are on the ends of strands of DNA and get shorter over time. At first these were considered very promising, but it turns out that their shortening doesn’t take place sufficiently uniformly to be a good estimate of biological age.

OK, you’ll have gathered that there’s no simple way to explain all this stuff in everyday language to us ordinary people. We’ll have to leave it to the experts, and they will have to advance the current state of the art very significantly before we get anything other than a convenient but necessarily inaccurate “give me a single number” estimate. Meanwhile, the authors of the paper stress that these markers are better than chronological age in measuring the progress of disease, and that calculators based on many of these biological age markers are ready for use in routine clinical practice.

So, what does this mean for us (by which I mean interested – indeed, fascinated – amateurs like me)?

I got three things out of all of it.

The first is that I’m extremely curious about what my biological age might be, no matter how rough and inaccurate any one estimate may be, particularly if it’s calculated entirely, not on medical measurements, but on lifestyle-based questions (as the vast majority that I’ve come across seem to be). So I wouldn’t take that type of result seriously; they’re just a very, very rough indicator, not such as to make anyone change their lifestyle (unless they get a series of results all of which suggest that their biological age might be much higher than their chronological age).

The second is that it seems definitely possible to slow down the rate at which we age biologically. You won’t be surprised to learn that it’s the usual suspects that are invoked, to achieve this: a healthy (or fast-mimicking) diet, regular physical activity, stress management, and actions of that sort. Indeed, it seems it’s even possible to reverse biological aging. T-cells are designed to seek and destroy specific pathogens; and early experiments suggest that it’s possible to take T-cells from our blood, alter them in the lab, and inject them back into the same person to fight a particular type of cancer. Certainly it seems that when these experiments are carried out on mice they have been successful.

The third is that our biological age doesn’t change at a uniform rate, but seems to increase in spurts at specific times in our lives.  More on this in the next blog post.

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Takeaway

Studying biological age is technical, much more so than the lifestyle-based questions that purport to tell us our biological age.

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