People ask me all the time why I run. They assume it's about burning calories or fitting into smaller pants. It's not. As a mechanical engineer, I run for a reason that has everything to do with how engines wear out — and almost nothing to do with the bathroom scale.
Let's get this out of the way. If you started running last month hoping to lose 10kg by summer, I have some bad news: it probably won't work. Not because running is useless — but because the math is ruthless.
A solid 30-minute run burns roughly 300 calories. That's a single blueberry muffin. One. You sweat, you suffer, your knees complain — and one careless trip to the cafe undoes the whole thing.
The honest truth: You cannot out-run a bad diet. Weight loss happens in the kitchen, not on the pavement. If shedding kilos is your only goal, fix what's on your plate before you buy new running shoes.
So if running isn't really a weight-loss tool, why do I lace up four mornings a week? Because of what's happening underneath my ribs.
The heart is a muscle. Like any muscle, it adapts to load. When you run regularly, you force the heart — especially the left ventricle, the chamber that pushes oxygenated blood out to the rest of the body — to handle a higher workload.
Over time, that chamber gets thicker, stronger, and bigger. The walls become more efficient. Each contraction pushes more blood out per beat. This is called an increase in stroke volume.
And here's the beautiful consequence: if your heart can move more blood per beat, it doesn't need to beat as often. So your resting heart rate drops.
Imagine two cars sitting in a parking lot.
Car A is idling at 3,000 RPM all day. The engine sounds aggressive. Pistons are flying up and down. Valves are slamming open and shut. Bearings are spinning under load. Heat is building. Friction is building. Oil breaks down faster. You can practically hear the parts wearing out in real time.
Car B is idling at 800 RPM. Calm. Smooth. The engine is barely working. Same job (sitting still), drastically less stress on the moving parts.
Now — which car do you want to own ten years from now?
Obviously Car B. Lower RPM means less wear on the pistons, less stress on the valves, fewer bearing rotations, less heat, less friction. Mechanical components have a finite number of cycles in them before they fail. The fewer cycles you spend per minute, the longer the engine lasts.
Your heart works on exactly the same principle. Every beat is one mechanical cycle. Valves opening and closing. Muscle contracting and relaxing. Each beat has a tiny cost. Multiply that cost by minutes, hours, decades — and the difference between an idle of 75 bpm and an idle of 40 bpm becomes enormous.
Here's why this matters. Compare an average adult ticking along at 75 bpm to a trained runner at 40 bpm.
| Metric | Average Adult (75 bpm) | Trained Runner (40 bpm) |
|---|---|---|
| Beats per minute | 75 | 40 |
| Beats per hour | 4,500 | 2,400 |
| Beats per day | 108,000 | 57,600 |
| Difference per day | 50,400 fewer beats | |
Fifty thousand beats. Per day. Now scale that up.
Almost a billion beats. That's a billion fewer mechanical cycles your heart has to perform. A billion fewer valve closures. A billion less wear on the most important piece of moving hardware in your body.
You can't buy a replacement heart at the parts store. So saving a billion cycles — that's not a small thing.
Lower resting heart rate is the headline. But running quietly hands you a few other gifts on the side:
None of those are the reason I run. They're just included in the box.
Don't run because you want to be skinny. Run because you want your heart to last. Run because every easy morning kilometre is a deposit into your cardiovascular savings account. Run because your left ventricle deserves better.
Don't run for the scale. Run for the heart muscle that has to keep clocking in for the next 50 years. FEWER REVOLUTIONS, LONGER LIFE.