The world's oldest person, 116-year-old Gertrude Weaver of Arkansas, believes the key to longevity is treating other people kindly.

Weaver, born on July 4, 1898, lives at a senior care facility in Camden, Arkansas, where she exercises in her wheelchair three times a week and eats three meals a day at the facility's dining room.

"I treat everyone the way I want to be treated," Weaver told reporters on her 116th birthday when she received a letter from President Barack Obama. She is the world's oldest person according to the Gerontology Research Group of Los Angeles.

The daughter of sharecroppers was born in Arkansas near the Texas border and worked as a domestic helper.

After retiring, she lived with her granddaughter and moved to Silver Oaks Health & Rehabilitation Center in 2009 when her granddaughter had health problems, the facility's administrator, Kathy Langley, said.

"She's an absolutely amazing lady," Langley said.

Weaver's 93-year-old son visits on a regular basis.

"She said she has been blessed with a long and healthy life because of the way she has treated others," Langley said.

Misao Okawa, a Japanese woman recognized as the world's oldest person who credited her longevity to "eating delicious things" and getting plenty of rest, died at the age of 117 on Wednesday, Japanese media reported.

Okawa was recognized by the Guinness Book of World Records as the world's oldest person in June 2013 when Jiroemon Kimura, also from Japan, died at the age of 116 years and 54 days.