"I've been thinking a lot about why I have been pushing so hard, so soon," Miles O'Brien says.

Editor’s Note: Dr. Sanjay Gupta has been following former CNN correspondent Miles O’Brien’s recovery after the amputation of O’Brien’s left arm. On July 12 and 13, O’Brien is participating in the 300-mile Less Cancer Bike Ride from Port Huron to Mackinac, Michigan. Follow CNN for more on his story.

Story highlights

Earlier this year, Miles O'Brien's left arm was amputated after an accident

O'Brien plans to ride his bike 300 miles from Port Huron to Mackinac, Michigan

O'Brien says his struggle "pales by comparison" to cancer

CNN  — 

I’m tired of being surrounded by cancer. Over the past two years, I lost my sister, my mother and nearly lost my girlfriend to breast cancer and its complications.

It’s an epidemic, and it seems we all just accept that as fact. I think it’s high time we said: enough.

My lifelong friend Bill Couzens has been similarly affected by cancer. He has made it his life’s mission to change the way we think about this dreaded disease.

It’s a different way of fighting a war on cancer: Instead of focusing on treatments, drugs and experimental surgeries, it looks at what is going on in our environment and what we are eating, and considers what role those factors might play in the cancer epidemic.

It’s not a popular place on the spectrum of debate about cancer. Frankly, the corporations that pollute our environment and process our food don’t want to go anywhere near the message that comes from LessCancer.org. It is simply not good for business.

So I am riding to help people think about what causes cancer. Sure, there is a genetic component to all of this. But that’s just part of the story.

The other part of the story for me, is a very personal journey. Four-and-a-half months ago, I had an accident that led to the amputation of my left arm. One of my goals for returning to normalcy was to get back on a bicycle – something that was very important to me before I lost my arm.

I probably wouldn’t have decided to ride 300 miles over two days without the LessCancer.org event. As a matter fact, if I did, you might think I was a little bit crazy. As it is, a lot of people think it is ill-advised to set the bar so high so soon after my accident.

And I’ve been thinking a lot about why I have been pushing so hard, so soon.

Over the past few weeks I have been talking with CNN Chief Medical Correspondent Dr. Sanjay Gupta about my recovery. During my time with Sanjay, he repeatedly expressed incredulity over the pace that I have been keeping since I returned to my life minus an arm.

He, like so many others, wonders if I’m going too fast and not taking enough time to pause, reflect and grieve.

When I stop to think about it, I too wonder if I am ultimately doing myself a disservice. Should I be spending more time taking care of myself? But then I think about how I would feel if I put myself on the sidelines at this point.

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I would be left wondering what I can do and what I may not be able to do. I simply need to know now. There might be a time bomb of grief ticking inside me that will explode later, but at least I’ll know my abilities when that time comes.

I also think about the challenges that I have set for myself. Three months after the accident, I was with my longtime friend and colleague Kate Tobin camping on a Denali glacier in Alaska for a story we are doing on climate change. We snowshoed for miles, and I was shooting a lot of video in some very arduous conditions – including at the bottom of a 15-foot hole in the ice.

I had definitely jumped into the deep end of my first big assignment after the accident. I was really nervous about how it might go, but after we had done the trip and we were sitting in the airport for our respective flights home, Kate turned to me and said, “I didn’t see a bit of difference in your performance on this trip.”

I could not have asked for better medicine than that.

So I guess setting big goals in short order isn’t such a bad idea, assuming you reach them. This goal – 300 miles on a bicycle in two days – is a reach, to be sure. But I am going to do my best.

I have a fallback plan or two, including a tricycle called “Monomano” that is ideally suited for a one-armed rider, and a cousin who has a tandem bicycle with a seat reserved for me. If all else fails, there’s always the sag wagon for a segment or two.

But here’s what will keep me pedaling: I will be thinking about my sister, my mother, my ex-mother-in-law, both of my grandmothers, my girlfriend and everyone else I know whom I lost or nearly lost to cancer.

Their courage and grace while fighting this disease is an inspiration to me and should be to all of us. Yes, I have a new challenge in my life, but frankly it pales by comparison when I consider what it’s like to be caught up in the cancer epidemic.

We must find a way to stop it. I am neither a doctor nor a scientist – although I play the latter on TV! But in reality, what can we do? For me, the answer is to pedal hard and long to Mackinac.