QUINCY (CBS) – Ruth Kundsin proves the point that you are never too old. She’s 103, and just watching her workouts will make you tired.

She works with a personal trainer at the South Shore YMCA every Friday. And on Friday, she let us in on her secret. “You’ve got to have something to look forward to. That is the secret,” said Ruth, who has plenty to look forward to.

Like her workouts at the Y in Quincy. “Oh, I love to come here. I like it because not only do you do exercise, but you meet people,” she said.

Ruth was born in 1916, when World War I was raging. She didn’t retire until she was 81 after a long career as a microbiologist. “I have 150 published papers and five books,” she said.

Before coming to the Y she was a swimmer who took gold in the Senior Olympics. Now she works with personal trainer Dick Raymond. “She approached me about 10 years ago, when she was 93 years old,” Dick said.

Since then it’s become a regular Friday thing, starting with a cardio routine and moving on to strength training with Dick calling the shots. “He pushes you so you’re sore. If you’re not sore it didn’t do any good,” Ruth explained.

She knows she’s healthier because of the exercise, but it’s also the social aspect that works for her. “Because I think it helps you to say alive. I really do. And by the time you’re through you’re ready to go to bed. I am! I go home and I take a nap,” Ruth said laughing.

Ruth is writing a book about her career and the discrimination she faced as a woman who was a scientist, and about growing old. She says most books about aging are written by younger people who just don’t know the subject like she does.