For his book, "The Blue Zones," adventurer and author Dan Buettner spent years studying various corners of the world where life expectancy is the longest.

In his travels, Buettner met 104-year-old Giovanni Sannai of Sardinia, who started his day with wood-chopping and a glass of wine. Buettner told NPR that he challenged Sannai to arm wrestle, and the old man won.

You probably won't win arm-wrestling matches at that age. But you can add years to your life.

Here are five tips for increasing longevity:

Eat Food

Food expert and author Michael Pollan lives by a wise seven-word manifesto: Eat food. Not too much. Mostly plants. What people often eat, he says, is not food but processed substances and chemicals that can lead to all kinds of diseases, from heart ailments to diabetes. Those strip years off your life.

Here's more advice from Pollan:

Don't eat anything your great grandmother wouldn't recognize as food. (Portable yogurt tube? No.) Don?t eat anything with more than five ingredients, or ingredients you can't pronounce. Don't eat anything that won't eventually rot. Enjoy meals at a table, with family, at regular meal times. Leave the table a little bit hungry.

Have Sex

In a CNN story earlier this year, the network featured yoga instructor Sadie Nardini and her husband, who made an early New Year's resolution: sex every day for the month of December.

The two made the vow to help curb their appetite for cigarettes and chocolate, and it worked, they said. But they also discovered the sex helped them sleep better, gave them more energy, and Nardini said they didn't get the winter colds they typically do.

Research generally supports the notion that more sex leads to healthier lives.

Men who have sex three times a week can decrease their risk of heart attack and stroke by 50 percent, said Drs. Michael Roizen and Mehmet Oz, who together wrote a book, "You: Being Beautiful." Men who have 150 to 350 orgasms a year can feel two to eight years younger, and regular sex can decrease general pain, the doctors said.

Respect Your Body

You have to exercise to live longer -- there is no way around this one. So turn off "The Biggest Loser" and get outside. Perhaps the best advice here is the most simple: Find exercise you enjoy and make it a high priority in your life. Get creative. Find activities you are willing to do for the long term.

Oz, a surgeon and TV health guru, offered these other tips for men (from among his top 25 greatest health tips, listed in Men's Health magazine):

Don't pamper your back -- taking to bed will make a bad back weaker; it's better to get moving.

Drink green tea as an alternative to coffee and sugary drinks. It's full of heart-boosting and cancer-stopping polyphenols.

Know your digits. These include blood pressure (ideally it should be below 115, over 75), LDL cholesterol (under 100), resting heart rate (under 70), and fasting blood sugar (under 100). For every point a man's body mass index is over 25, testosterone drops 3 percent, which, Oz notes, isn't very manly.

Rest. Oz says seven hours of sleep helps lengthen lifespans, lowers stress, sharpens memory and reduces food cravings.

Another tip: floss. Research shows that bacteria that lingers in the mouth ends up in the bloodstream and can increase risk of heart disease.

Cut Stress / Connect With Family

In the nine tips outlined in Buettner's "Blue Zones" book, four of them (reduce stress; belong to a community; keep family first; surround yourself with people who have similar blue zone values) fall under this heading.

Stress corrodes healthy living and leads to bad habits that shorten lives: drinking, smoking and junk food, researchers say. Look for ways to reduce stress: exercising, playing games, walking, sex, gardening -- any hobby you enjoy. Draft a to-do list and then set a realistic plan for getting it all done. Simple breathing exercises can help slow a racing mind.

Experts also recommend people talk through problems even when -- especially when -- it seems really hard to do. It's been suggested that one reason women live longer is because they form closer networks of friends and lean more often on support groups. Financial experts note that money is the most common stressor for many men and they recommend facing any cash problems head-on and putting a plan in place to solve them.