Casey Stillwagon is a teacher, ultrarunner, and mental health advocate based in Tokyo, Japan, and the human behind the uplifting Instagram account @Run5555km.

Along with the mantra, Stronger Every Stride, Casey shares messages of hope, self-compassion, and quiet resilience to remind others, especially those struggling, of the inner strength we all carry.

Earlier this year, Casey launched a personal challenge: to run 5,555 kilometers in one year. The number 5, as you’ll hear, carries special meaning.

But the goal is about more than distance or personal achievement.

It’s about sharing the message that we can all grow stronger, physically, mentally, and emotionally, one stride at a time.

Casey has completed several endurance races, including the Fuji 5 Lakes Ultra and, most recently, the Fuji 3 Lakes Ultra Marathon, and is now quietly training for his ultimate goal: Japan’s largest 100-mile trail race, the Mt. Fuji 100.

Running hasn’t just strengthened his body and mindset — it has transformed his life. It became a healthy outlet for coping, processing, and navigating life’s challenges. It helped him quit smoking while in the Navy, achieve three years of sobriety, and continue pushing beyond what he once believed was possible. Ultimately, running helped him build a life grounded in values, discipline, clarity, and a deep sense of purpose.

In this conversation, Casey shares what running has taught him about emotional growth, why grace and self-compassion are vital for mental health, and what he’d tell his younger self.

We also talk about the difference between pain and suffering, the toughness resilience requires, and how @Run5555km helps him stay motivated, and the message he hopes to send to anyone struggling: “What you’re looking for is inside of you."

⚠️ Content Warning:

While our focus is on mental health, resilience, and inner strength, this episode briefly mentions a loved one’s suicide attempt in 2013. We recognize this topic may be sensitive for some. Please check in and take good care of yourself. If this is a topic that may be emotionally sensitive, pause, and consider listening when you’re in a space that feels private, supported, and right for you. Thank you.

If you’re struggling:

Please don’t carry it alone. There is help, and people who care. Talk to a therapist, counselor, or someone you trust. For immediate support — whether for yourself or someone else — the Suicide & Crisis Lifeline is available 24/7. Call or text 988, or visit 988lifeline.org.

U.S. Veterans: Dial 988 and press 1, or visit veteranscrisisline.net.

Support in Japan:

• TELL Lifeline (English): 0800-300-8355 | telljp.com/lifeline
• Inochi no Denwa (Japanese): 0570-783-556 (10am–10pm)
• Tokyo Suicide Prevention Center: 03-5286-9090 (8pm–6am daily; from 5pm on Tuesdays)
• Emergencies: Call 119 (ambulance/fire) or 110 (police)

Cited in Episode:

• Book | What I Talk About When I Talk About Running by Haruki Murakami
• Races | Fuji 5 Lakes & 3 Lakes Ultra Marathons
• Song | One More Light by Linkin Park (Official Video)

Connect with Casey:

Instagram: @run5555km

If Stronger Every Stride resonates with you, consider joining the movement. Whether you run 5,555 km in a year like Casey or follow your own pace, share your progress and tag @Run5555km with #StrongerEveryStride or #Run5555km to help spread mental health awareness and hope.

For 1:1 Coaching with Kari, visit KariWatterson.com