How Resistance Training Changed Everything In My Life

How a decade of only cardio ruined my health. And how resistance training changed everything.

For most of my adult life, I believed cardio was the key to fitness. Running, cycling, and swimming felt like the ultimate way to stay in shape. I followed the conventional wisdom: burn calories, stay lean. I enrolled in numerous marathons and even triathlons to keep myself motivated to continue doing cardio. And for a while, it seemed to work—I stayed relatively fit and maintained a decent weight.

But something started to feel off as I entered my late 30s. Despite all the cardio, I wasn’t feeling strong. My muscle mass had dwindled, and I started noticing little things—struggling to carry groceries, feeling weak when getting up from the floor, and worst of all, I could barely carry my two-year-old son for long without feeling exhausted. That was my wake-up call.

What I didn’t realize at the time is that excessive cardio, without strength training, leads to muscle loss over time. Studies show that prolonged endurance training, while excellent for cardiovascular health, can cause the body to prioritize endurance over muscle preservation. Over time, the body starts to break down muscle tissue to fuel long-duration activity, a process called muscle catabolism.

Additionally, after the age of 30, we naturally lose muscle at a rate of 3-8% per decade, a process known as sarcopenia. If we don’t actively resist this loss through strength training, we set ourselves up for weakness, poor mobility, and even increased risk of injury as we age. I was unknowingly accelerating this decline by neglecting resistance training.

Realizing my mistake, I made the switch. I started lifting weights and incorporating progressive overload. I focused on compound movements like squats, deadlifts, push-ups, and pull-ups, which build functional strength.

The results were dramatic. Within months:
My muscle mass increased, while I still stayed lean.
I no longer struggled to carry my son or do daily tasks.
My posture improved, and joint pains disappeared.
I looked healthier than I ever did during my cardio-only years.

Balanced approach is key, especially in your 40s

Now that I’m in my 40s, I’ve learned that a well-rounded fitness approach is what truly keeps the body resilient. Cardio alone won’t cut it. Instead, a combination of:

Resistance Training (3-4x per week) – To maintain and build muscle mass, protect joints, and increase metabolism.

Cardio (2-3x per week) – To support heart health and endurance, but in moderation.

Stability & Mobility Work – Such as core training and flexibility exercises to prevent injuries and maintain functional movement.

Looking back, I wish I had started resistance training sooner. The fitness industry often glorifies being lean, but real health and longevity come from strength. If you’re in your 30s or 40s building muscle, stability, and endurance together is the real formula for long-term health.

Now, when I pick up my son, I don’t struggle. I feel strong. And that’s the best feeling in the world.