My Ironman Journey With Cystic Fibrosis

Training for an Ironman race is no easy feat, especially when living with cystic fibrosis. But I'm more determined than ever to push my limits, make my younger self proud, and prove to others that nothing is impossible.

June 24, 2025 | 6 min read
A headshot of Jack Stoutenberg
Jack Stoutenberg
Jack riding a bicycle on a rural road

When I tell people I’m training for a full Ironman competition, their reactions range from raised eyebrows to outright disbelief. It involves swimming 2.4 miles, biking 112 miles, then running a full 26.2-mile marathon — all in one day. It’s a challenge for anyone. But I also have cystic fibrosis with double F508del mutations. That detail tends to change the tone of the conversation. 

I was diagnosed with CF on September 11, 2001. Twice-daily treatments, a handful of pills with every meal, hospital stays, blood tests, and doctor’s visits — it all became routine. I never knew life without these activities. As a kid, I didn’t fully understand the gravity of the disease. I thought all kids had to inhale sodium chloride before school and Pulmozyme before bed. I assumed everyone carried a vest machine and a bag full of meds on vacations or took countless enzymes with every meal. 

It wasn’t until I got older that I realized most people never have to think about those things. My parents were incredibly supportive and never made me feel different from the other kids in my class. They always emphasized the importance of staying active for my health. After football or lacrosse practice, I vividly remember coughing up thick, sticky mucus. My face and equipment would be covered in dry patches of white salt — something I just thought was normal for everyone. But CF causes the body to lose far more sodium through sweat than the average person, and it showed. 

The hardest part of growing up with CF was the mental battle. On the outside, I looked healthy and active. But CF is an invisible disease. No one saw the daily grind, the exhausting routines, or the internal worry. As I got older, that invisible weight grew heavier. I always felt like there was a clock ticking in the background. 

After graduating college, I had to decide what the next chapter of my life would look like. Just before starting college, I started taking Trikafta — a breakthrough modulator drug that completely changed my life. Gone were the morning cough attacks and the constant mucus. I even felt good enough to stop using my vest for airway clearance. For the first time, I had a new outlook on life. I wanted to make the most of it and push myself further than I ever thought possible. For years, I didn’t believe I would ever have that kind of opportunity. After studying abroad and reflecting on my life, I made the decision: I was going to complete a full-distance Ironman. 

I began training in September 2024, and I’ve made a lot of progress since then. I swim, bike, and run at least three times a week. It’s a lot, but I don’t take any of it for granted. I walk a tightrope every day — pushing my limits while staying healthy. One of my biggest challenges has been managing sodium loss. People with CF lose much more salt in their sweat than the average person. I did a sweat test to calculate exactly how much sodium I lose during workouts and how much I need to replenish. This is critical — especially for a race that will most likely last over 12 hours. Fueling and hydration can be the difference between finishing and collapsing. 

I’ve had setbacks, though. During my annual glucose tolerance test, my blood-sugar levels dropped to a critically low 34 mg/dL. My doctors and family were extremely concerned. I was immediately placed on a continuous glucose monitor to see how extended cardio sessions were affecting my body. After ten days of tracking, we felt comfortable removing it, but I remain hyper-aware of what I eat and when. I have to consume energy constantly during workouts, and I’ve found that liquid calories are the easiest and most effective. 

I understand that not everyone with CF has access to the same health advancements or the ability to exercise at this level. I recognize the privilege in that and I don’t take it lightly. My hope is that my journey gives someone else in the CF community something to believe in. A future filled with possibility. 

Ironman training requires an intense level of mental toughness. Continuous hours of solo workouts have given me time to reflect on where I’ve been and where I’m going. Growing up with CF forced me to develop resilience early, so that mental discipline has come more naturally than I expected. Still, I keep pushing. When I want to quit, I think about everything I’ve been through — the doctor’s appointments, the treatments, the self-doubt — and I keep going. Even when it hurts. Even when I’m exhausted. I keep showing up for myself, again and again, because there was a time when I felt like I couldn’t. I hated that feeling. So now I chase the opposite: strength, belief, and progress. 

I’m doing this race to show my younger self that I’m capable of anything I set my mind to. And if you’re reading this — whether you have CF or love someone who does — I hope you feel that too. 

I’m working toward becoming the youngest person with CF to complete a full-distance Ironman. I’ve been sharing my story to raise awareness, and hopefully, to inspire others to take on something hard — something that scares them. Because right now, I have the chance to push myself further than ever before. 

From where I started to where I’m headed, this is about more than one race. It’s about proving that no diagnosis, no expectation, and no limitation can define what we’re capable of. 

Because we are capable of so much more than we think. 

Interested in sharing your story? The CF Community Blog wants to hear from you.

Disclaimer

This site contains general information about cystic fibrosis, as well as personal insight from the CF community. Opinions and experiences shared by members of our community, including but not limited to people with CF and their families, belong solely to the blog post author and do not represent those of the Cystic Fibrosis Foundation, unless explicitly stated. In addition, the site is not intended as a substitute for treatment advice from a medical professional. Consult your doctor before making any changes to your treatment.

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A headshot of Jack Stoutenberg

Jack was born with cystic fibrosis and is currently training to become the youngest person with CF to complete a full-distance Ironman triathlon. A graduate of University of Oregon, he is passionate about pushing past perceived limitations and raising awareness for the CF community through his athletic journey. You can follow Jack’s journey on YouTube

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