Today, American actor Dick Van Dyke celebrates his 100th birthday.

Many remember the star for his roles in  Disney's "Mary Poppins," Roald Dahl's "Chitty Chitty Bang Bang," and starring in his own sitcom series, "The Dick Van Dyke Show." Over the years, he has surprised many with how energetic and alert he still is in his old age. 

In the lead-up to his 100th birthday, the star shared how he has managed to live a long life across various interviews. It all narrowed down to two factors: having a positive outlook and never getting angry. "I’ve always thought that anger and hate is one thing that eats up a person’s insides,” shared the actor in an interview with People magazine. "And I never really was able to work up a feeling of hate. There were things I didn’t like, people I don’t like, and disapprove of. But I never really was able to do a white heat kind of hate." 

Having a positive outlook on life has been shown to be one factor for living longer. Managing stress levels, after all, reduces the production of hormones like cortisol. Cortisol is responsible for many bodily functions, like keeping your blood pressure in check, controlling your sleep schedule, and managing how your body distributes sugar for energy. High levels of stress can increase hormone levels, leading to weight gain, weakness, high blood sugar, and high blood pressure. 

Aside from living a happy life, Dick also leads an active lifestyle. The actor has shared how he goes to the gym three times a week, continues to dance as much as he can, and attributes his wife, Arlene Silver, for keeping him young. Regular exercise, especially as you get older, helps keep your bones and muscles healthy. By keeping the body active, it drastically reduces the risk of chronic diseases like heart disease, stroke, and type 2 diabetes.