How New Research Shows We Don’t Age Evenly

If you’re in your early forties or late fifties, get ready for an “aging spike.”

This is how I feel now, and I’m only in my thirties.Photo byVladimir Soares on Unsplash

As much as I wish it weren’t so, I’m starting to feel my age.It’s a little harder to stand up, and I get envious when I see kids at the park throwing themselves into somersaults. But new research, published in August in the peer-reviewed journal Nature Aging, suggest that the two biggest bursts of aging may still be ahead of me.

Specifically, they hit in the mid-forties and early sixties.

This isn’t based on counting wrinkles or counting how many times someone groans “oh god” as they try to stand up after sitting for a while on a bare floor, but is instead based on biological markers — signal molecules and bacteria, present on our skin, in our blood, and in our intestinal tract.

One of the surprising targets in the first wave? Caffeine and alcohol.

The molecular signals of aging

How do we measure age?

On the surface, it seems like an easy question, but it gets tricky to pin down details. Anecdotally, we all know someone who seems surprisingly old for their age, and someone else who seems strangely fit and healthy. There are a whole spate of models that try to use measurements to estimate an individual’s “biological age”.

Related: What is Biological Age, and Does it Tell Us Anything Useful?

For some of us, our cells may look much older than the calendar suggests

(Spoiler alert: it’s useful at the population level, but there’s too much variation between individual people to use any sort of biological age estimate as a basis for health treatments or personalized recommendations.)

In this recent paper, the researchers looked at samples of many different molecules, across 108 individuals, over a varying period of time (between 1.7 to 6.8 years). The grand total was a staggering 135,239 different biological markers measured, for an insane 246,507,456,400 total data points!

So, what did they find?

Lots of different markers/molecules changed as people got older. But most of them didn’t change linearly — that is, most of them did not steadily increase or decrease over time.

Instead, they tended to change in big jumps, which occurred around age 40 and age 60. Whether looking at microbes, DNA, proteins, or specific types of fats, the levels would change most significantly at these two ages.

Some of these noted changes include:

• At age 60, there’s a decrease in components linked with our ability to remove damaged cells or cell components, reducing our body’s ability to “clean up” its own damage.
• Around age 60 there’s a notable drop in kidney function, as well as a markedly higher chance of type II diabetes onset.
• Around age 40, there are changes suggesting a decrease in our ability to metabolize caffeine and alcohol. This changes a second time around age 60, dropping off further.
• Around age 60, there’s a significant drop in activity related to our blood cells’ ability to efficiently carry oxygen.

Are there shortcomings or limits to this study?

No study is perfect, and the authors take care to note in their Discussion section that their observations have limitations.

First, although the researchers set this study up to be longitudinal (it follows the same individuals for a period of time), it’s still on a pretty small cohort. There were only 108 total participants, and only 8 of those subjects were between ages 25 and 40. These were also all people living in northern California near Stanford. People in other locations might age differently.

Additionally, even though researchers collected samples from their participants for several years, none of the individual participant data spans even a single decade. It’s a bit unreasonable to ask someone to allow invasive repeated health tests for 50+ years, but there might be influences from our environment that may change over time.

Finally, there’s the ever-present issue of correlation versus causation. These findings give us valuable insights about when we may expect body changes,or when it may be best to start monitoring for a certain condition (increased type II diabetes screenings starting at age 55?). But we can’t use these to zoom in to an individual level.

Overall, as a population, our bodies are less able to handle caffeine and alcohol after age 40. But this doesn’t mean that for you specifically, as an individual, your tolerance is suddenly going to drop.

What can I do to minimize these effects of aging?

Unfortunately, there’s no silver bullet (or graying bullet, haha?) for aging. And while these results show that aging may happen at certain predictable intervals, we have found that lifestyle choices can help cushion the impact.

In other words, your body will still go downhill. But your lifestyle choices help you start from a higher place — or to climb back up that hill a bit.

For example, muscle is typically lost at around 1–2% per year, but that threshold is easily overcome on a shorter term with resistance training. Building more muscle now means that, even as it’s slowly lost, you will retain more strength than someone who didn’t train at all.

Similarly, managing insulin resistance when younger can help delay or prevent type II diabetes in the future. (How do you do so? No great surprise; maintaining a healthy weight, regular exercise to help muscle cells retain insulin sensitivity, and eating a healthy diet.)

We can also recognize that we may need to make lifestyle changes as these “aging breakpoints” approach. Knowing that you may become more sensitive to caffeine or alcohol, for example, may prompt you to skip that second cocktail or late-afternoon cup of joe.

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Aging doesn’t happen evenly, year by year. At certain approximate ages, our early forties and sixties, the aging process seems to “jump up” a level and we may see a sudden reduction in our abilities and vitality.

We can’t prevent this age-related decline from occurring entirely, but we can always make improvements to our lifestyle to counterbalance it. Many senior athletes have demonstrated that it’s never too late to start training or to adjust our lifestyle.

In the meantime, I’m going to also make sure that I don’t book any booze cruises to celebrate turning 45 or 62!

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