100-year-old worked full-time, raised 3 kids, and hasn't missed a day of journaling in nearly 90 years: Her secrets to a long, happy life

In 1935, 10-year-old Evie Riski's father gifted her a diary for Christmas and marked the start of a 90-year journey for the North Dakota native.

Riski, now 100 years old, has journaled every single day since January 1, 1936.

As a child, Riski typically wrote about "the things that happened that day, or what the weather was like, or just simple things," she tells CNBC Make It. Even a quick browse through her diaries can tell you what the weather was like in North Dakota at just about any point over the last nine decades.

Living on a farm also gave Riski a lot to write about. One of her early diary entries from August of 1937 reads, "washed, churned, cleaned, church. Baked."

"Every night she'd pull out that book and sit at the kitchen table and write," says Michelle Locken, Riski's daughter.

"I don't know how she did it all these years, because she worked all the time [at a meat processing plant her and her husband ran] and raised three kids. Had a husband with heart disease, took care of her mom and dad. I mean, just always go, go, go."

Regardless of what the day brings, Riski devotes 15 minutes a day to her journaling, she says. Even when she was in the hospital after giving birth to her children, she'd write, according to The Washington Post.

"I wrote on scrap paper then and transferred it to the diary when I got home," Riski told the publication. "There was really no excuse for me not to write in it."

It's a habit that Locken, 59, has developed herself: "It's very encouraging to me. I've been doing it for 15 to 20 years. I just have a bunch of books."

When asked what she thinks contributes to a long and happy life, Riski says, "You need to work hard. Just strive to work harder all your life."

She tells people who want to live to 100 to "keep doing your exercise, staying active, eating all the right foods, or try to."

Wellness has always been important to Riski. She's taken vitamins since she was 18, was very into cycling and participated in bowling leagues with her husband and her friends.

For her diet, "I like homemade meals. I don't like processed [foods] at all," she says.

Even at age 100, Riski sticks to her health-conscious habits. "I offer her milk or a juice, and she says, 'No water is good for me,'" says Anna Halvorson, administrator at the Good Samaritan Society - Prairie Rose, where Riski lives.

"I think she's just relied on what is good for her, and she's been very consistent with those things all her life, and that has been inspiring."

Research shows that journaling can be great for a person's mental health because it can lower stress levels and help you process your thoughts.

These days, Riski says most of her diary entries are about how her children and grandchildren are doing.

Locken recalls her mother supporting her dreams early on, taking her to dance classes and magic shows and teaching her how to make special recipes.

Riski and her husband, Locken's father, always hosted parties and spent time with their friends.

"Evie has really found a way to have soaked up every last moment of her life, and documented every last moment of her life," Halvorson says.

"[She] really values her family and her family life. I think that's honestly one of her secrets to a long and healthy life. It's family."