The day we interviewed Lucille Singleton in her Harlem apartment, she greeted us at the door sporting a pair of neon orange running sneakers and a megawatt smile. At 10:30 in the morning, the energy that this 90-year-old generated put our mojo to shame.

Thrice weekly dialysis treatments and knee replacement surgery would slow down the average person, but not Singleton. The South Carolina native worked as a housecleaner, a nanny and a home health care worker before making  a career change to construction worker at the tender age of 71. This is a woman who started running in her late sixties, took on her first marathon at 75 and hasn’t stopped yet.

With her husband long gone and her son and daughter living in New Jersey, the fiercely independent Singleton fends for herself – and very well, thank you. Her apartment is decorated with her running trophies and medals, and while she won’t be sprinting across the New York City Marathon finish line this year (she has participated three times and placed in the top 10 in her age group every time) she will be out there volunteering, as she has done for years.

On the eve of the Marathon, we sat down to find out what makes Lucille run.

Lucille, you’re 90 – how old do you feel?

I don’t feel old – I feel 25 or 30. Just a few months ago, my primary care doctor told me that I had the heart of a 40 year old, and then my kidney doctor said “your primary doctor was wrong. He should have told you that you have the heart of a 25 year old! “

What do you know now that you wish you had known at 30?

I wish that I had started running earlier! When I was a little girl growing up in South Carolina, I used to go on errands for old people, and I would literally run to the store and back. They’d say, “Stop that running before you fall!” But it was fun for me. I didn’t know that people actually ran for fun until I got to New York. It’s the greatest thing that has ever happened to me, and I wish I had gotten started sooner.

You ran your first road race at 67 and your first marathon at 75. What motivated you?

When I was a home health aide, I was taking care of a lady, and her granddaughter showed up in running clothes. I asked her where she was off to, and she said, “The Road Runners Club.” I went in and signed up right away, at first just to volunteer. I love running – it’s my thing. I cut down, but I’ll never cut it out. I still run one mile; I used to do three. Feeling good motivates me. I get up at 4am and I am out the door; I run my route, up and down Eight Avenue. And I run early because there is no one out at that hour who’s going to stop me to chat.

How do you defy the odds?

I keep my body busy at all times and I’m up and out all day. I’ve been on dialysis for years and I have never been sick. I had knee replacement surgery six years ago, and the doctor said I’d never be able to run again. The first day I tried, it was not so good. The second day, I hopped along. Third day I said, “I’m gone!”  This was two months after surgery. That’s why I can do some much, because I never stopped doing what I do. I run every day, and my doctor doesn’t even know it…

You changed careers at 71. What would you say to people who are afraid of big changes?

Do it. After the lady I used to care for died, I stopped working for a few years, but then I realized that I needed to do something. My son and daughter said, “Ma, nobody will hire you.” I said, “I bet they will.” Nothing would stop me.

I heard about a construction job starting on 125^th Street. I bought a hard hat, boots, gloves and hammer and a belt and went to the site. The boss called me in and wanted to give me a job as a flagger, but I didn’t want that. He said, “But you can’t do what they’re doing – they’re doing demolition!” I said, “I can do that.” I wanted to move things around. He told me that they were starting in two weeks, but I showed up every day so that he wouldn’t forget about me. He looked at me and said, “You here again? You really want this job, okay, get started.” He told the guys to get me a hammer, but I already had my hammer! I was ready. So I started, pulling out windows and doors.

What does “aging with attitude” mean to you?

It means staying busy and keeping that body moving. I tell this to all older people – whatever you can do, you do it. If you stay at home looking at four walls, watching TV and eating, and that’s your life, that’s no good. Get out and about! Sometimes when I’m running on the street, the guys whistle. I tell them I am old enough to be their mother, or their grandmother. They say, “Hey, but you still look good!” I was married for many years, but my husband died in 1969. I had a few boyfriends but they were so slow, I had to get rid of them. But you know what? I’m still looking.

What does “aging with attitude” mean to you? Tell us in the comments box below.