“Exercise, eating healthy and drinking lots and lots of water.”

That’s how Ernestine Shepard (the woman in the video above) keeps herself looking fit and feeling good at “80 years young” as she calls it.

Exercise and eating healthy are rather vague, really, but she makes a great point about water. 75% of Americans are chronically dehydrated. Most of us simply don’t drink enough water. We drink a lot of coffee, tea, juice and soda–and alcohol–but that doesn’t count. In fact, most of those things contribute to dehydration and premature aging.

The standard formula is: your body weight, divided in half. Drink that much water in ounces per day. An example. You weight 150lbs. Drink 75oz of water per day.

But is that the secret? It’s hard to say, but it can’t hurt.

For as long as people have walked the earth, they have tried to figure out how to live longer. Luckily, modern record-keeping and statistics are giving us some clues.

Concentrations of centenarians

One way to get clues to longevity is to look at the countries or regions where people live the longest, then examine things like diet and cultural practices related to health in those places.

For example, the longest-living place in the world is around Okinawa, Japan. Here, people eat a diet high in fish and homegrown vegetables. They are known for keeping portion sizes small and even have a saying: “Eat until you are 80% full.” There is a documented sense of community in this place, where parents often live with their children in old age.

After that, southern Italy has a very high concentration of people over 100 years old. It is theorized that the Mediterranean diet has a lot to do with their longevity. It might be purely speculation if another nearby location wasn’t also among the top five regions for longevity: Ikaria, Greece.

Both of these cultures eat a diet high in fish, olive oil, olives and things like local sheeps and goat cheese.

Though not necessarily regional, members of the Seventh Day Adventist Church tend to live longer than most people. Their faith discourages tobacco and alcohol use, and they are also mostly vegetarians. An interesting case study: there is a town in Southern California called Loma Linda where there are more than 20,000 Seventh Day Adventists. The city’s life expectancy is 10 years higher than the U.S. national average.

Things like not smoking, not drinking and getting exercise are largely a given. But it’s interesting to note that fish (and healthy fats like olive oil and olives) seem to be a commonality. This even goes for Seventh Day Adventists, whose faith discourages meat, but fish is more widely accepted.

The mental component

A couple of interesting factors contributing to longevity seem to be related to attitude, outlook and social relationships. Cultures that include and embrace the older generations seem to produce more people who live past 100. It appears important to foster social relationships when it comes to aging.

Beyond that, the people who live to a ripe old age seem to be… happy. As one longevity researcher put it, Dan Buettner, “”Every main principle investigator [of a longevity study] will say it’s hard to measure likability, but the grumps seem to die out.”

Lesson? Don’t sweat the small stuff. Find the beauty. Take time to smell the roses and other such platitudes.

More scientifically, it’s likely a function of stress. It has very real physical manifestations. We all have it. Some of us learn to manage it better than others. Perhaps that’s the secret.

Thank you for going on this longevity journey with me. As the month of July, 2017 continues to progress, I’ll be exploring longevity in more depth. Stay tuned.