Why do I get so tired while swimming?

If there is a question that gets repeated very often, then it is this one:

Why is swimming so exhausting? I am in pretty good shape so I should be able to reasonably swim as well.

There are 5 main reasons for this.

1. We’re Heavier Than Water

When we’re in the water, 95% of our bodies are naturally submerged. This is very uncomfortable for us. We feel we’re going to sink and not be able to breathe! Our instincts don’t like it, so we try to keep our heads above the water by churning and kicking.

This is very exhausting.

2. We Are Unbalanced

For terrestrial animals the balanced and stable position is vertical. But for fish it is horizontal. This is what we need to learn – how to be horizontal in the water.

This is quite difficult for us because our legs are heavy and tend to sink. And this sinking causes that we create more resistance and we need to expend more energy.

3. We Are Unstable

Imagine that you are walking and then you slip. Out of a sudden, you feel threatened, start sweating and adrenaline shoots. You can’t say you feel well.

Now imagine that you have the same feeling all the time you swim. You feel unstable and you flail with your arms, kick furiously just to avoid that feeling of insecurity and danger. Again, a lot of energy wasted.

4. Moving Parts Of The Body

We have arms, legs, head, and torso and all of it moves. This constant movement causes that the shape of the body changes a lot. Look below how much the shape of the body can change during one stroke cycle.

In one moment he has quite a good, streamlined shape. But a moment later, he is shorter, wider and his shape is much less hydrodynamic. The wider we are the more water resistance we create.

5. We Swim Against A Wall

Water is appr. 900x dense than air. Moving through water creates a lot of resistance. And the faster we swim, the more resistance it is.


We just need to learn how to swim efficiently. I believe that the best way how to swim really well is to follow this swimming pyramid.

Swimming pyramid – how to swim efficiently
  1. Comfort. It all starts here. Without learning how to feel comfortable and secure in the water, you will always struggle and spend too much energy.
  2. Posture. Proper posture kept the whole time you swim will allow you to effortlessly glide forward through the water.
  3. Propulsion. Learn how to use your core to propel you forward.

Here I offer 4 tips what to do:

1. Hang Your Head

Swimmers usually experience the greatest tension in the neck. So it is very useful to focus on the muscles around the neck and completely release them. You can imagine that your head is completely weightless, “hanging” in the water.

2. Reach Deeper

When your arm enters the water, just reach deeper. Usually, we tend to keep it closer to the surface. But the higher the arm, the lower the legs and therefore more resistance.

If we reach deeper, the body is more horizontal and we are able to keep a more hydrodynamic posture.

3. Timing Of The Arms

Our instincts tell us to start stroking immediately. Because if we don’t, we think we will sink. This is very demanding and costs a lot of energy.

Instead of a constant arm movement, I suggest keeping the leading arm in front of the body until the other arm is ready to enter the water.

4. Whole Body Propulsion

The javelin thrower does not use only her arm to throw the javelin. She uses her whole body to create the most energy she can.

You can do the same while swimming – use your whole body to propel you forward. In freestyle, it means shifting weight from one side to the other. Watch the video below to see what I mean.

I suggest trying all the tips and see how it works for you. In the comment section, let us know how it worked for you.

Do you want to learn how to apply these principles step-by-step? If so, you can start with a video Freestyle Mini-Course.

Tomas Vojtechovsky
I have been a swim coach since 2004. I live in the Czech Republic. Triathlon brought me to swimming. When I first discovered triathlon in 1996, I fell in love with the sport. But swimming had always been a struggle and frustration. No matter how hard I tried, I could not get any better. So I began my journey by learning how to move through water efficiently and gracefully. I have practiced yoga and tai chi, the Alexander technique, Natural Movement on dry land. In water it was the Art of Swimming. But the greatest difference came with Total Immersion and for several years I had been a certified TI coach. Now I work on my own. I founded and developed the instruction and content for Totální plavání and Smart Swimming.

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