This question comes up constantly. Coaches say breathe every 3. Your lungs say every 2. Who’s right? Both — it depends on context.
The Case for Breathing Every 3
Symmetry: Breathing every 3 strokes means you alternate which side you breathe on each breath. Left, right, left, right. This forces both sides of your stroke to develop equally and prevents the asymmetries that come from always breathing to one side.
Technique: Breathing every 3 requires more controlled breathing and exhaling. You have to be efficient with your air. This tends to produce better exhalation habits (breathing out underwater, not holding your breath).
Open water: In open water, you need to breathe to either side depending on conditions (sun, waves, sighting). Breathing every 3 trains that flexibility.
Best for: Moderate-effort training, technique development, open water preparation.
The Case for Breathing Every 2
Oxygen supply: In hard intervals or sprint work, your muscles need more oxygen. Breathing every 2 strokes (every arm cycle) provides more frequent air exchange and supports higher intensity.
Comfort: For many adult swimmers, especially beginners, every-3 breathing causes anxiety and breaks their stroke rhythm. If you’re fighting to make it to the next breath, your technique suffers.
Hard sets: During threshold or VO2 max sets, most competitive swimmers breathe every 1–2 strokes. At race pace, you take air when you can.
Best for: Hard intervals, sprint work, when you need maximum oxygen.
The Practical Answer
For easy and moderate training: Practice breathing every 3 (bilateral). Build the habit when effort is low enough that you can focus on form.
For hard sets: Breathe every 2, or whatever allows you to maintain pace. Breathing frequency is a secondary concern when intensity is the goal.
For beginners: Start with whatever lets you swim without stopping. If that’s every 2, use every 2. As you get more comfortable, start introducing every-3 in your warm-up and cool-down.
Building Toward Every-3
If every-3 breathing feels impossible, the problem is usually insufficient exhalation underwater. Most swimmers who struggle with it are holding air in, so by the time they turn to breathe they feel desperate.
Fix: While swimming, exhale continuously and completely through your nose or mouth while your face is underwater. Turn to breathe only to inhale — a quick sniff, then back underwater and start exhaling again.
Practice this in your warm-up for 2–3 weeks. Once the exhale habit is consistent, every-3 breathing becomes much less stressful.
One Simple Rule
Start every session with every-3 bilateral breathing during warm-up. Use whatever rhythm you need during the main set. Return to every-3 for cool-down.
Over time, every-3 becomes your default rhythm, and your stroke becomes more symmetrical and efficient as a result.