Study author Michael Gurven, an anthropology professor and chairman of the University of California-Santa Barbara's Integrative Anthropological Sciences Unit, and colleagues tracked 2,296 indigenous adults in 82 Tsimane villages, an area in the tropical lowlands of Bolivia's Amazon basin.
Tsimane are lowland forager-horticulturalists -- population estimated at 11,000 -- subsisting on plantains, rice, corn, manioc, fish and hunted game.
"The Tsimane living conditions are similar to those of our ancestors, with greater exposure to pathogens, active lifestyle, high fertility and traditional diet. Studying chronic diseases in these populations can be very insightful," Gurven said in a statement.
"Per decade, Tsimane women had a systolic blood pressure increase of 2.86 millimeter of mercury and a diastolic blood pressure increase of 0.95 mm Hg, while Tsimane men had a systolic blood pressure increase of 0.91 mm Hg and a diastolic blood pressure decrease of 0.02 mm Hg."
About 3 percent of Tsimane adults had high blood pressure, compared to 33.5 percent of U.S. adults, Gurven said.
The study published in the journal Hypertension suggested lifestyle factors specific to hunters-gatherers that might explain the minimal increases in blood pressure in the Tsimane included: High physical activity, low stress levels and potentially protective diets high in fruits, vegetables and potassium and diets low in calories, salt and alcohol.