Does Running Really Make You Age Faster?

Whenever I tell friends that I’ve started running, I often hear the same comments:

“Your knees will be ruined.”
“You’ll age faster if you run.”

But is that really true? In this post, I整理 a YouTube episode from Running Behind and look at what science actually says about running and aging.

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I. Which Type of Exercise Helps Slow Down Aging?

1. Study Design and Results

In 2019, researchers recruited 124 healthy but mostly sedentary adults and divided them into four groups:

• No exercise
• Aerobic exercise only
• High-intensity interval training (HIIT) only
• Strength training only

The three exercise groups trained for six months, doing their assigned workout three times a week, 45 minutes per session.

After six months, the researchers measured the activity of an enzyme called telomerase, which is closely related to cellular aging.

• No-exercise group & strength training group: little to no change
• Aerobic & HIIT groups: telomerase activity increased significantly

In other words, aerobic exercise like running actually helped slow down biological aging at the cellular level.

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II. Why Does “Running Makes You Look Old” Feel So True?

If running boosts anti-aging enzymes, why do so many people still believe that running makes you look older?

Imagine meeting an old friend after years:

“Wow, you’ve lost so much weight.”
“Yeah, I’ve been running a lot lately…”
“No wonder you look older. If you keep running like that, you’ll age faster. Take it easy!”

If you’ve met people who are really into marathons, sometimes they do look older than their age — tanned skin, less facial fat, more wrinkles. So the phrase “Running makes you age” can feel very real.

But there are two big misunderstandings hiding in that sentence.

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III. Two Misconceptions Behind “Running Makes You Age”

1. The Difference Between “Running” and “Marathon Training”

When we say, “I run these days”, many people automatically hear, “I train for marathons.”

In reality, only a small portion of recreational runners actually move on to regular marathon training.

• If you can run about 10 km in one go, you can call yourself a recreational runner.
• Once you complete 42.195 km at least once, you’re more like a beginner marathoner.

At the recreational level, the feedback you hear is usually something like:

“Your jawline looks sharper.”
“You look much healthier these days.”

Not,

“Why do you look so old all of a sudden?”

Even people who complete a full marathon once or twice don’t usually look dramatically older.

The people who sometimes “look older” are usually those who:

• Train hard for multiple marathons every year, and
• Spend long hours outside under direct sunlight.

At a normal recreational level, running is very unlikely to be a direct cause of aging.

2. What We Really Mean by “You Look Old”

In Korean, when we say someone “got old,” the literal meaning is “the body has become weaker with age.”

But in everyday life, when people say “Running makes you age faster”, they usually mean:

“Your face looks older than before.”

In other words, they are talking about how old your face looks (photo-aging / premature aging)