Proper breathing technique is fundamental to the freestyle stroke. Following are some rules and exercises for perfecting your bilateral breathing.
Rule: As with one-sided breathing, it's important to exhale fully whenever your face is in the water. Holding your breath even a little makes you tense up and causes the sensation that you can't get enough oxygen. But it's really a buildup of carbon dioxide in your lungs that you're struggling with. A popular saying in swimming: Blow them bubbles, and it'll end your troubles.
Drill: Sinking exercises are good for this. An example? Go to the deep end and tread water. Then take a deep breath and let yourself sink down. As soon as your head is underwater, begin exhaling forcefully but smoothly. The goal is to be able to sink all the way to the bottom of the pool and stay there, exhaling the entire time, until you need to push off the bottom and come back up.
Rule: Coordinate your strokes with your breathing.
Drill: While standing in the shallow end with your head in the water, take a few practice stationary strokes, using your arms and repeating bubble, bubble, breathe on right side; bubble, bubble, breathe on left side.
Rule: Rotating your body properly helps you breathe more efficiently and effortlessly.
Drill: As you're swimming, imagine that you're breathing through your navel, so that with each breath, you roll your entire body -- not just your head -- up toward the sky. As you do this, concentrate on keeping everything from the top of your head to the tip of your toes in perfect alignment.
For lots more information about the freestyle stroke and bilateral breathing, visit the next page.