You’ll probably hear the same confession from any marathon runner who has jumped into a pool for the first time in years: two lengths in, lungs burning, arms suddenly made of concrete. It’s an odd humility. They can run for hours without complaining, but here they are, clinging to the lane rope as if it were the only thing that is solid. The majority of coaches who witness it frequently will tell you that it is not a fitness issue. It’s a breathing issue.
When a swimmer holds their breath underwater and then tries to gulp down air in the half-second their face clears the surface, a specific type of panic sets in. It turns out that, contrary to popular belief, holding your breath does not actually save oxygen. It accomplishes something more akin to the opposite. When a breath is eventually taken, the body is already behind its own need for air because carbon dioxide accumulates in the blood with nowhere to go. The solution, according to the majority of swim instructors, sounds almost too straightforward: instead of holding everything in and exhaling in a single, frantic burst, breathe out slowly and continuously underwater, a technique known as trickle breathing.
| Category | Information |
|---|---|
| Topic | Fatigue while swimming freestyle |
| Primary cause | Inefficient breathing technique (breath-holding vs. trickle breathing) |
| Secondary cause | Poor body position increasing drag |
| Common misconception | High aerobic fitness from running/cycling transfers directly to swimming |
| Key fix | Two-beat kick for distance swimming instead of relying on leg power |
| Recommended practice | Interval sets (e.g., 8x50m) rather than continuous long swims |
| Expert consensus | Swimming-specific fitness develops only through frequent, consistent pool time |
| Reference resource | U.S. Masters Swimming – Breathing Technique Guide |
Sitting with how counterintuitive this feels is worthwhile. Swimming seems to imply holding still, holding air, and holding tension in every way. The swimmers who appear to be barely trying those who glide past while everyone else thrashes have typically forgotten that instinct. There’s a certain loose, almost bored efficiency to watching them glide by, as if the water isn’t fighting them the way it fights everyone else.
From outside the pool, it’s easy to overlook the subtle role that body position plays in this situation. Legs sink. It is caused by the head sitting too high and the weight distribution tilting backward, and almost everyone experiences it at some point. Pressing the chest into the water, akin to leaning on a beach ball, is a common cue used by coaches. It may seem strange at first, but once you try it, you’ll notice that your legs rise on their own. Almost instantly, there is less drag. It’s one of those minor changes that initially seem to have little effect but eventually have a significant impact.
Then there’s the kick, which most novice swimmers believe requires more effort than it actually does. Because leg muscles are big, strong, and designed to move both on land and in water, their size becomes a liability. Even during a full sprint, they contribute perhaps 30% of the total propulsion, requiring massive amounts of oxygen for comparatively little forward motion. A more sustainable two-beat kick typically outperforms the urge to thrash harder over longer distances. Distance swimmers have relied on this unglamorous advice for generations, and there’s a reason it hasn’t gone out of style.
All of this falls short of explaining why running a few lengths can be so much more taxing than, say, a five-mile run. Swimming fitness is peculiar in that it is very specific, limited, and nearly unyielding in its lack of transferability to other sports. Because the muscles and lungs haven’t adapted to this specific type of effort, a person who runs marathons every weekend might still feel exhausted after four lengths of crawl. Unfortunately, repetition is the only effective cure. Ideally, there should be two sessions per week, but even one extra session beyond what’s going on right now usually makes a difference.
Another structural trick that is sometimes disregarded is dividing distance into intervals instead of trying it all at once. Surprisingly, swimmers frequently discover that they can extend that to ten or twelve rounds once the rhythm takes hold, covering more total distance with less pain along the way. Eight rounds of fifty meters with twenty seconds of rest in between often proves more sustainable than one continuous four-hundred-meter swim.
In all of this, it’s difficult to ignore a pattern. It’s not always the case that those who appear to swim effortlessly are stronger or more athletic. The tiny, imperceptible ways that subtly deplete energy the held breath, the sinking hips, the overworked kick have simply stopped them from battling the water. Depending on the individual, it may take weeks or months to unlearn that. It appears that patience is more rewarded by the water than strength.
i) https://www.swimnow.co.uk/stroke-improvement/how-to-swim-freestyle-without-getting-tired/
ii) https://blog.myswimpro.com/2023/02/22/how-to-swim-without-getting-tired/
iii) https://www.usms.org/fitness-and-training/guides/freestyle/breathing
iv) https://www.quora.com/I-get-tired-very-quickly-when-swimming-freestyle-but-not-when-I-use-a-pull-buoy-What-do-I-likely-do-wrong
v) https://effortlessswimming.com/why-you-get-tired-so-quickly/