Living a long time isn't just about good genes, a new study says. 4 lifestyle changes that can improve your longevity.

If you have a parent or grandparent who’s reached their 90s or even become a centenarian, someone’s probably said to you, “Oh, you have good genes!” But if longevity doesn’t seem to run in your family, fret not: Lifespan has more to do with your lifestyle and environment than with your genetics, according to a study published in the journal Nature Medicine.

In other words, there’s a lot you can do to take control of your own destiny when it comes to longevity, regardless of how long your relatives lived. Here’s what to know.

What the study found

Using data on nearly half a million people from the U.K., Oxford University researchers looked for patterns in who died prematurely, or before the age of 75. They also looked at markers of biological aging in a smaller subset of the study group (over 45,000 people). Their analysis included comparisons of genetic risk factors for disease as well as what some scientists have termed the “exposome.” Our DNA makes up our genome, whereas the exposome is made up of all the exposures we encounter throughout life. This includes everything from what we eat, drink and inhale to the neighborhoods we live in.

While genetics accounted for less than 2% of the difference in people’s risks of death, environmental factors were behind 17% of the disparity, the scientists found. Smoking, socioeconomic status — a measure of factors like income, neighborhood, education and occupation — physical activity levels and living conditions had the greatest influence on someone’s biological aging and risk of death.

Some of these factors — such as how much money you make or whether you can afford to own a home in a nice neighborhood — are hard to change. But overall, 23 out of 25 of the environmental variables the researchers looked at are modifiable. And many of them are pretty simple.

Do genes not matter when it comes to longevity?

No, they definitely do. But to what extent varies a lot depending on the specific genes, the diseases that they put you at risk for and what you do throughout your life. For example, which variants of the APOE gene you carry is highly predictive of your risk for Alzheimer’s disease; the same goes for BRCA1 and BRCA2 variants and breast cancer. And these diseases can have a lot to do with your biological aging and life expectancy.

But even these genes are influenced by your behavior and environment. And, in most cases, our choices and the lives we lead have a huge impact on what those genes will mean for our health. “Someone put a comment on our paper, saying ‘genetics loads the dice, but it’s up to us to play our hand,’” Austin Argentieri, a research fellow at Massachusetts General Hospital who led the new study while he was a researcher at Oxford Population Health, tells Yahoo Life. Even if your genetic makeup predisposes you to diseases that could cut your life short, “in most cases, you can mitigate that risk through lifestyle, behavior, or taking different drugs or treatments,” explains Argentieri.

Changes that can set you up for a longer life

1. Don’t smoke.

By now, it’s hardly a surprise that smoking is bad for you. But, aside from a person’s age, smoking has a greater bearing on longevity and aging than any other factor — genetic or environmental — according to the new study. Second to age, the factor that most influenced mortality risk was “smoking pack years,” meaning the number of packs of cigarettes a person smoked daily, for how many years. And smoking status — whether someone currently, formerly or never smoked — was the fourth-most-influential factor (sex was third; men are more likely to die earlier than women). “If you can do one thing, don’t smoke,” says Argentieri.

2. Get good sleep.

People who are tired frequently or don’t get very much sleep at night are more likely to both age quickly and die prematurely. How much sleep you need varies from person to person, but for most adults, you should aim to get seven to nine hours a night. And try to have good “sleep hygiene” by going to bed and waking at consistent times, having a bedtime routine, keeping your room dark and keeping your phone away from your bed.

3. Get moving.

After tiredness, physical activity “is close in the running for the top” factor influencing biological aging and risk of death, says Argentieri. That’s in part because many of the chronic conditions that accelerate aging and lead to early death are cardiometabolic diseases, such as heart disease, diabetes and stroke. Obesity increases risks for these conditions, while exercise, in combination with a healthy diet, can reduce those risks. Diet may have more influence, but “that doesn’t mean that exercise shouldn’t be part of the plan,” Valter Longo, a University of Southern California professor of gerontology who studies how nutrition and fasting can influence longevity, tells Yahoo Life. In combination with other habits, exercising can help you live healthier, for longer.

4. Eat for longer living.

The study found that while what people ate didn’t have much effect on their biological aging, it was predictive of their risk of death. That may be because many people change their diets to be healthier because they have a health problem, such as prediabetes. But Longo’s research suggests that eating a diet that consists of lots of plants and fish and little red meat is associated with a longer life. A diet that includes sufficient but low levels of protein helps to prevent aging acceleration by altering the way certain genes associated with the breakdown of our bodies work, Longo says (though this changes around age 65, when we need more protein, he notes).