A 101-year-old says the key to his longevity is refusing to act his age

• Jack Weber, 101, maintains a youthful mindset to stay active and engaged in life.
• Despite losing his wife and friends, Weber chooses to embrace the present.
• Weber's daily routine includes exercise, outdoor activities, and a positive outlook.

Jack Weber is 101 years old. He's outlived his wife, buried all of his best friends, and lived through a world war, the Great Depression, and pandemics. And yet, every morning, he wakes up with a sense of purpose and gratitude.

"My attitude is 'Don't let the old man in,'" Weber said. "If you think young, you're more likely to act young."

Weber embodies that mindset through his lifestyle and relationships, and he believes it's the key to his longevity.

He doesn't let grief stand in his way

Weber met his wife, Betty, in college. He still remembers the moment she asked him to be her lab partner in anatomy class.

"My mother didn't raise a stupid kid. So I jumped at the chance," he said. "She went from a lab partner to my college sweetheart."

They were married for 57 years, raised five children, and had 11 grandchildren.

When Betty died in 2004 after a decadelong battle with breast cancer, Weber didn't think he would outlive her for so long.

"It's not easy," he said. "She should still be here, sitting next to me."

Weber has also lost all of his closest friends. "I'm the last man standing," he said.

But rather than retreat into grief, Weber chose to keep moving, literally and emotionally.

"My kids said to me, 'Dad, you've got to get back into life again. You've got too many good years ahead of you, too many things that you want to do, and you've grieved enough,'" he said. "So I did follow their advice. I have gone on with my life."

He refuses to complain

Weber has moved in with one of his daughters and says he works hard not to become a burden.

"I don't complain. If I have something that is bothering me, I will not bother other people with my problem," he said. "Do I have some aches and pains? I sure do. But I don't talk about them, and I don't let them run my life."

He doesn't sugarcoat aging. He admits to forgetting names, walking more slowly, and feeling the effects of time in his body.

He has also started using a cane since he fell on his patio and fractured a bone.

"I'm determined not to fall again," he explained.

But he doesn't let those things define him.

"I refuse to think that I can't do this or I can't do that," he said.

He still exercises every day, stretching, lifting light weights, and riding a stationary bike for about 20 minutes. He also drives his own car.

"I don't push myself to do something I don't think I can do," he says. "I think that's important because you physically could hurt yourself doing something like that."

The outdoors keeps him motivated

Since he was a child, his mother encouraged him to enjoy the outdoors, even when he had homework.

"She took my books, closed them, and said, 'You do your homework after dark, after the sunshine is gone,'" he recalls. "'Right now, you go outside and play because that's the healthiest thing to do.'"

That has become his life motto.

If the sun is out and it's not cold, he'll put on a coat, sit on his patio, and take in the warmth.

In the summer, he'll trade the stationary bike for the pool.

"I do water walking at the shallow end, water comes up to my chest," he said. "That water is very resistant. And I try to do 40 laps."

But his favorite outdoor hobby is golf.

"I have become very good friends with the golf professional at the course, and he always introduces me to the people, 'Here is our legend. He's a legend of this golf course,'" Weber said. "It makes me walk home with my chest out and feeling like a million dollars. I feel that if I can be an inspiration to somebody, that makes it all worthwhile."

This story is adapted from Business Insider's video series "Life Lessons." Watch the full video below or on YouTube: