Analysis of Breathing in Swimming (English Version)

One of the most confusing aspects of swimming to athletes that are not used to the water is breathing. In most sports, breathing is something we take for granted. Air is always around for us and there for the taking. Not so when your face is planted in a swimming pool or lake! Taking too few breaths in the open water will reduce your oxygen supply, which can cause you to tire rapidly. Of course, taking too many breaths causes you to slow down. How do you know if you are breathing too little or too much?

This experiment is designed to understand the time loss associated with breathing in freestyle. A series of laps were completed by Duane Dobko in a 25 yard pool at maximum possible speed where the number of strokes per breath was controlled. The breathing patterns were completely randomized. The time of each lap was taken with a stopwatch and recorded.

Overall Results

Figure 1 shows that the time lost per breath is 0.0441 seconds. This number is very small, unless you are a 50 meter swimming sprinter and every hundredth of a second matters. It is too small to be of much worry for triathletes. If you found a way to reduce the number of breaths you take in a race by 20, your overall swim time would not even improve by 1 second! The precise effects of reducing your breathing rate for some of the common triathlon swim distances are shown in Figure 2.

Figure 1: Results – 25 yard sprint times with various breath holding patterns

Figure 2

Figure 2 illustrates just how insignificant 0.0441 seconds per breath means to triathletes. If you switched from 2 strokes per breath to breathing 8 strokes per breath for an entire 2.4 mile Iron distance swim, your projected time would only improve by 52 seconds. For most of us, this gain would be more than offset by the increased fatigue due to lack of oxygen! The result suggests that breathing as much as possible is the way to go, even breathing every stroke. However, a more detailed analysis suggests otherwise. The trade-off to breathing a lot lies in the corresponding increase in variation.

Analysis of Variation

The overall consistency of swim times was evaluated with different breathing rates. The intent is to determine if different breathing patterns create more or less variable results. The variation in strokes per breath is summarized in the Box/Whisker plot in Figure 3.

Figure 3 – Box / Whisker plots (definition of Box / Whisker on right)

Click on image for larger version.

The standard deviation (a measure of variation) increased a whopping 80% when the number of breaths per length increased from 2 to 9. The result says that a higher breathing frequency increases swimming speed variation. This makes sense, as head movement will tend to disrupt body positioning. This is why most swimmers find it easier to swim evenly with a snorkel.

Any increase in variation of swimming speed has negative consequences for the triathlete in open water. As the athlete speeds up and slows down, their body position in the water must also rise and fall, forcing more water movement and greater energy expenditure to attain the same speed compared to a swimmer who swims more evenly and stays higher on average in the water. In other words, when you breathe more, you must work harder and use more energy to go the same speed. It can be projected that the inefficiency will add up over the long distances of open water swims in triathlon, increasing fatigue and decreasing total speed.

Overall Testing Conclusions

So, what can a triathlete take away from this experiment? The data indicates to take as many breaths as needed, but no more. If you can get away with breathing every four strokes, then that is what you should do. If you start to get oxygen depleted, it is okay to breathe every 2 strokes. You will not lose a lot of time with this decision. However, be aware that your entire stroke will be less efficient when you breathe more. You must determine for yourself if this decrease in efficiency is going to be made up by the increase in oxygen intake. If you feel like you are drowning or suffocating, chances are that breathing more often is going to work well for you. If there is enough air in the tank, then charge ahead and don’t look up.