That’s according to new research presented Monday at the American Society for Nutrition’s annual conference in Boston.

Researchers examined the data of nearly 720,000 military veterans ages 40–99, who were followed over time. Those who adopted eight healthy habits saw a 13% reduction in mortality compared to those who did not.

Forty-year-olds who adopt all eight healthy habits could gain between 23 (for women) and 24 (for men) years of life expectancy, according to the research team, mostly comprised of Harvard- and Department of Veterans Affairs–affiliated scientists in Boston.

The benefits of positive lifestyle tweaks were only studied among veterans, Xuan-Mai Nguyen—a medical student at the Carle Illinois College of Medicine in Champaign, Ill., and a researcher on the study—tells Fortune. But it makes sense that they would benefit civilians as well.

“These lifestyle factors are not new ideas, and for the general population to incorporate them into their lifestyle could promote general well-being,” she says.

8 lifestyle tweaks that could lengthen your life

So, just what are the eight healthy habits that apparently extended the lifespan of hundreds of thousands of veterans?

1. Never smoking: Life expectancy for smokers is at least 10 years shorter than it is for nonsmokers, according to the U.S. Centers for Disease Control and Prevention. The good news: If you quit smoking before age 40, you can reduce the risk of dying from a smoking-related disease by about 90%.
   
2. Being physically active: In the study, those who got 30 minutes or more of moderate or vigorous physical activity a day were considered to be physically active. Such people should be able to walk up a flight of stairs without getting winded, according to Nguyen.
   
3. Not regularly binge-drinking: Study participants whose peak daily alcoholic beverage consumption in the past month was four drinks or less were not considered to be binge drinkers. Those who consumed five or more drinks in one day on their heaviest drinking day in the past month were considered to be binge drinkers.
   
4. Getting good sleep: Participants who got, on average, seven to nine hours of sleep a night and didn’t suffer from insomnia were considered to have good sleep. Insomnia was defined as having one or more of the following symptoms: difficulty initiating sleep, difficulty maintaining sleep, and/or early-morning awakenings, along with sleep that isn’t refreshing or excessive daytime sleepiness.
   
5. Eating a healthy diet: Those who generally adhered to a plant-based diet were considered to have a healthy diet.
   
6. Living a minimal-stress life: Chronic stress advances one’s biological (or epigenetic) clock, potentially shortening their life span, according to a 2021 Yale-based study. Thankfully, relaxing can set that clock in reverse.
   
7. Having positive social relationships: Loneliness is a greater risk factor for early death than obesity and physical inactivity, comparable to the risk associated with smoking and drinking, some studies have found. In fact, U.S. Surgeon General Dr. Vivek Murthy declared loneliness a public health epidemic this year. When it came to the study, participants were considered to have positive social relationships if they had someone to talk to, hug, or otherwise interact with at least 50% of the time.
   
8. Avoiding opioids: U.S. opioid deaths hit a record high in 2021, according to federal data, seemingly fueled by pandemic isolation. Those who use opioids like hydrocodone, fentanyl, and oxycodone for more than two weeks are at risk for addiction. Medications exist to treat those with opioid use disorders, and to make quitting more bearable. But they’re not always readily accessible, according to a White House fact sheet.

The three most impactful habits when it came to extending life span: exercising, not being addicted to opioids, and not smoking. Those who didn’t have these healthy habits were 30%–45% more likely to die during the study.

Stress, binge drinking, poor diet, and not getting good sleep were associated with around a 20% increase of death during the study. A lack of positive social relationships added a 5% increased risk of death.

While adopting all eight factors by age 40 is ideal, adopting even one—or a few—at any point in life helps, researchers say. A 60-year-old with all eight healthy habits could expect to see just under 20 years’ gain, and an 80-year-old around 10 years. A 40-year-old with just four of the healthy habits saw about a 10-year increase in life expectancy, and an 80-year-old around five years.

“The earlier the better, but even if you only make a small change in your forties, fifties, or sixties, it is still beneficial,” Nguyen says.