There comes a time in most entrepreneurs' lives when they realize a simple truth: Money is valuable, but time is more valuable. And while none of us lives forever, there are some things we can do to live a bit longer. 

In fact, a massive new study suggests that eight fairly simple health habits can add 20 years to people's predicted lifespan – an extra 21 years of predicted life expectancy for women who follow them, or an extra 24 years for men. 

As presenting author Xuan-Mai T. Nguyen, a health science specialist at the US Department of Veterans Affairs who is also a rising fourth-year medical student at Carle Illinois College of Medicine, explained:

We were really surprised by just how much could be gained with the adoption of one, two, three, or all eight lifestyle factors. Our research findings suggest that adopting a healthy lifestyle is important for both public health and personal wellness.

The earlier the better, but even if you only make a small change in your 40s, 50s, or 60s, it still is beneficial.

The data was compiled from medical questionnaires and records collected between 2011 and 2019 from 719,147 people associated with a large Veterans Affairs study, and the findings were set to be presented last month at the annual meeting of the American Society for Nutrition in Boston.

I'm going to outline all eight of these habits below. For what it's worth, I found it useful to remember an old saying as I read them: "The best time to plant a tree was 20 years ago. The second best time is now."

Here are the habits, ranked in increasing order of how much time they can add to your life (as percentages), according to the study:

1. Having positive social relationships

The longest-running longitudinal study in history found that good relationships were the most important factor in a long and happy life. Likewise, this study suggests having good relationships led to a 5 percent predicted effect on longevity.

2. Managing or avoiding stress

Some stress is unavoidable, but this habit was associated with 20 percent additional longevity. While not part of the study, here's a compendium I put together a year ago including five simple ways to calm anxiety, including listening to a specially designed song, and controlling your breathing in a specific way.

3. Avoiding binge drinking

The emphasis here seems to be avoiding "binge" drinking, not never drinking alcohol at all, and it also was associated with 20 percent additional longevity. 

In fact, some studies have suggested that light to moderate drinking (one to two drinks per day) can have a positive effect on longevity. "I have no explanation for it," said one study lead, "but I do firmly believe that modest drinking improves longevity."

4. Having a sensible diet

Again: a 20 percent effect on predicted longevity. This factor probably doesn't surprise many people, as it's the one bit of advice we've received since we were kids (although the agreed upon composition of a smart diet has certainly changed). One bit of advice? Eat more vegetables.

5. Having good sleep hygiene

Here's another habit that probably isn't a big surprise. It has the added bonus of being enjoyable. I've written a lot here over the years on improving sleep hygiene. 

My two favorite studies are probably this one, laying out exactly how much sleep most people need, and this one, suggesting the benefits of a specific sleep position. Overall, sleep hygiene was associated with 20 percent expected longevity.

6. Having sufficient physical activity

Again, there are so many other studies, and I doubt you'll be shocked by this one. 

But as an example, researchers at Brigham Young University reported a few years back that they've found that a certain type of physical exercise can slow the aging process within our cells – to the point of someone appearing biologically nine years younger. 

In the current VA study, lack of physical activity was associated with a 30 to 45 percent higher risk of death.

7. Not using opioids

To be clear on this one, the habit is not having an opioid use disorder, as opposed to never using prescription opioids. Still, the effect on predicted longevity was estimated in the same 30 to 45 percent category.

8. Never smoking

Pure nonsmokers had the same 30 to 45 percent expected longevity effect. Again, it's not surprising; I've previously reported on studies that suggested smoking correlates to a seven year shorter life expectancy.

We should make clear that our old friend, causation versus correlation, is at play here, in that we can't say for sure whether any of these specific habits actually causes longer life; only that longer life is observed at scale among people who practice them. 

It's an important difference that can seem subtle, and I hope it won't dissuade anyone (myself included) from placing greater emphasis on these habits. Because if you dedicate your life to building things – a business, an industry, even a legacy – it only stands that you'd want to live long enough to enjoy what you've created. 

"Lifestyle medicine is aimed at treating the underlying causes of chronic diseases rather than their symptoms," Nguyen said in a statement accompanying the report, adding: "It is never too late to adopt a healthy lifestyle." 

Inc