Why do people age differently?

The following piece was adapted from the book The Telomere Effect by Elizabeth Blackburn.

Why do people age at different rates? Why are some people whip smart and energetic into old age, while other people, much younger, are sick, exhausted, and foggy? You can think of the difference visually:

Look at Kara’s healthspan; the first white part of the bar shows the time of her life when she’s healthy and free of disease. But in her early 50’s, the white turns gray, and at age 70, black. She enters the diseasespan. These are years marked by the diseases of aging: cardiovascular disease, arthritis, a weakened immune system, diabetes, cancer, lung disease, and more. Skin and hair become older looking, too. Worse, it’s not as if you get just one disease of aging and then stop there. In a phenomenon with the gloomy name multi-morbidity, these diseases tend to come in clusters.

So Kara doesn’t just have a run-down immune system; she also has joint pain and early signs of heart disease. For some people, the diseases of aging hasten the end of life. For others, life goes on, but it’s a life with less spark, less zip. The years are increasingly marred by sickness, fatigue, and discomfort. At 50, Kara should be brimming with good health. But the graph shows that at this young age, she is creeping into the diseasespan. Kara might put it more bluntly: she is getting old.

Lisa is another story. At 50, she’s still enjoying excellent health. She gets older as the years pass, but she luxuriates in the healthspan for a nice, long time. It isn’t until she’s well into her 80’s - roughly the age that gerontologists call “old old”—that it gets significantly harder for her to keep up with life as she’s always known it. Lisa has a diseasespan, but it’s compressed into just a few years toward the end of a long, productive life.

How can one person bask in the sunshine of good health, while the other suffers in the shadow of the diseasespan? Can you choose which experience happens to you?

Many people have come to believe that nature is all that determines aging (your health is mostly controlled by your genes, determining your risk for heart disease, cancer, and general longevity before you’re even born.).Explaining why Kara is aging so much faster than her friend, they might say: “Her parents probably have heart problems and bad joints, too.” “It’s all in her DNA.” “She has unlucky genes.”

But many have noticed that the quality of our health is shaped by the way we live. it’s your health habits that really count.

Here’s what these folks might say about Kara’s early aging: “She’s eating too many carbs.” “As we age, each of us gets the face we deserve.” “She needs to exercise more.” “She probably has some deep, unresolved psychological issues.”

Actually, both views are critical, and it’s the interaction between the two that matters most. The real differences between Lisa’s and Kara’s rates of aging lie in the complex interactions between genes, social relationships and environments, lifestyles, those twists of fate, and especially how one responds to the twists of fate.

You’re born with a particular set of genes, but the way you live can influence how your genes express themselves. In some cases, lifestyle factors can turn genes on or shut them off. As the obesity researcher George Bray has said, “Genes load the gun, and environment pulls the trigger.” His words apply not just to weight gain but to most aspects of health. This is where you’ll find telomeres (tee-lo- meres), repeating segments of noncoding DNA that live at the ends of your chromosomes. Telomeres, which shorten with each cell division, help determine how fast your cells age and when they die, depending on how quickly they wear down.

Telomeres, which shorten with each cell division, help determine how fast your cells age and when they die, depending on how quickly they wear down. The extraordinary discovery from research labs around the world is that the ends of our chromosomes can actually lengthen -and as a result, aging is a dynamic process that can be accelerated or slowed, and in some aspects even reversed. Aging need not be, as thought for so long, a one-way slippery slope toward infirmity and decay. We all will get older, but how we age is very much dependent on our cellular health.

Your telomeres, it turns out, are listening to you. They absorb the instructions you give them. The way you live can, in effect, tell your telomeres to speed up the process of cellular aging. But it can also do the opposite. The foods you eat, your response to emotional challenges, the amount of exercise you get, whether you were exposed to childhood stress, and even the level of trust and safety in your neighborhood - all of these factors and more appear to influence your telomeres and can prevent premature aging at the cellular level. In short, one of the keys to a long healthspan is simply doing your part to foster healthy cell renewal.