The world's healthiest hearts belong to an indigenous group in Bolivia, according to researchers.

A study in the British medical journal The Lancet says the Tsimane people of the South American nation show barely heart problems, including those who live well past their 60s.  The Tsimane (pronounced chee-may-nay) hunt, fish, and farm on the Maniqui River in the Amazon rainforest in the Bolivian lowlands in pretty much the same way they have for thousands of years. 

Coronary artery calcium (CAC) is the leading cause of death in advanced countries and its prevalence is increasing among the developing countries.  It clogs up arteries and increases the risk of heart attack.  But the Tsimane have practically no problem with CAC.  Researchers examined 705 people's hearts in a CT scanner, and found that almost no Tsimane at the age of 45 had CAC; by age 75, two thirds of the group remained CAC-free.  Compare that with burger-loving Americans, 80 percent of whom have CAC at that age.

"It is much lower than in every other population where data exists," said University of California at Santa Barbara anthropology professor Michael Gurven.  "The closest were Japanese women, but it's still a different ballpark altogether."

The Tsimane are incredibly active; men average 17,000 steps a day, while women walk 16,000 steps.  Even people aged older than 60 years have a step count over 15,000.

Their diet is reminiscent of the paleo diot craze:  It's 17 percent game; Aussies probably won't find too much wild pig, tapir, and capybara at Woolworths, but if you wanted to emulate the Tsimane, you'd pick lean meats.  Seven percent of their diet is fish.  The other 76 percent is family-farmed rice, maize, a potato-like root called manioc, and plantains.  Typically, these would be cooked in a stew along with whatever game was hunted that week, and topped off with a handful of foraged nuts and berries.

But beyond replicating their diet and exercise levels, there's something else to consider:  Lifestyle.  "They also live in small communities, life is very social and they maintain a positive outlook," says Dr Gregory Thomas, one of the researchers and from Long Beach Memorial Medical Center near Los Angeles, California.