Swimming Breathing: Techniques, Physiology, and Training for Underwater Efficiency

How do swimmers breathe underwater?

Swimmers do not truly "breathe underwater" in the way marine animals do; rather, they master specific techniques to efficiently exhale underwater and then quickly inhale above the water's surface, synchronizing these actions with their stroke mechanics to maintain propulsion and minimize drag.

Understanding Human Respiration and Swimming

Unlike aquatic animals, humans lack gills and cannot extract oxygen directly from water. Our respiratory system is designed for gaseous exchange with atmospheric air. Therefore, the phrase "breathing underwater" in the context of swimming refers to a highly refined process of breath holding, controlled exhalation while submerged, and precise inhalation when the mouth and nose clear the water. This intricate dance of physiology and biomechanics is fundamental to efficient swimming.

The Physiology of Breath Holding and Exertion

When a swimmer is submerged, they are holding their breath. This triggers a series of physiological responses:

• Oxygen Consumption: The body's muscles continue to consume oxygen to fuel movement, leading to a decrease in blood oxygen levels (hypoxia).
• Carbon Dioxide Buildup: Simultaneously, metabolic processes produce carbon dioxide (CO2) as a waste product. This CO2 dissolves in the blood, forming carbonic acid, which lowers blood pH. It is primarily the buildup of CO2, rather than the lack of oxygen, that creates the strong urge to breathe. Chemoreceptors in the body are highly sensitive to CO2 levels, signaling the brain to initiate respiration.
• The Dive Reflex (Mammalian Dive Reflex): While more pronounced in prolonged apnea, a milder version of this reflex can occur, causing a slowing of heart rate (bradycardia) and peripheral vasoconstriction (narrowing of blood vessels in extremities) to conserve oxygen for vital organs. In swimming, its effect is generally minimal compared to the conscious control of breath.

Efficient swimming breathing techniques aim to manage these physiological changes, allowing for sustained activity without excessive discomfort or performance decrement.

Core Breathing Techniques in Swimming

Different swimming strokes necessitate distinct breathing patterns, all centered on minimizing interruption to streamline and propulsion.

Rotational Breathing (Freestyle and Backstroke)

This is the most common technique for freestyle (front crawl) and is adapted for backstroke.

• Freestyle:
  • Head and Body Rotation: Instead of just lifting the head, the swimmer rotates their head to the side, aligning it with the rotating body. This allows the mouth to clear the water with minimal disruption to body position. The lower goggle lens remains partially submerged, creating a "bow wave" that forms a pocket of air for inhalation.
  • Timing: Inhalation typically occurs during the recovery phase of the arm stroke on the breathing side. The breath is taken quickly and smoothly.
  • Exhalation: Crucially, exhalation begins immediately after the previous inhalation and continues underwater through the nose and/or mouth. This clears the lungs of CO2 and prepares them for a fresh intake of oxygen.
• Backstroke: Breathing is less restrictive as the face is generally out of the water. However, controlled breathing is still important for rhythm and to prevent hyperventilation. Swimmers often take quick breaths between strokes or hold their breath for a few strokes before exhaling and inhaling.

Bilateral Breathing

This technique involves alternating breathing sides (e.g., every three or five strokes in freestyle).

• Benefits:
  • Symmetrical Development: Promotes balanced muscle development and body rotation.
  • Improved Body Awareness: Enhances proprioception and kinesthetic awareness.
  • Adaptability: Useful in open water swimming to navigate waves or sunlight.
• Mechanics: The same principles of rotational breathing apply, simply alternating the side on which the breath is taken.

Frontal Breathing (Breaststroke and Butterfly)

These strokes require lifting the head forward to breathe.

• Breaststroke:
  • Head Lift: As the arms complete their out-sweep and begin the in-sweep, the chest and head lift forward and slightly upward, clearing the water for inhalation.
  • Timing: Inhalation occurs during the recovery phase of the arm stroke, typically every stroke.
  • Exhalation: Exhalation occurs underwater as the face re-enters the water and the body streamlines.
• Butterfly:
  • Forward Lift: The head lifts forward and slightly upward, leading the chest, as the arms complete the pull-through phase.
  • Timing: Breathing can occur every stroke or every other stroke, depending on the swimmer's endurance and race strategy.
  • Exhalation: Similar to breaststroke, exhalation is performed underwater as the face re-enters.

The Biomechanics of Efficient Swimming Breathing

Beyond the physiological aspect, proper breathing technique is critical for maintaining hydrodynamic efficiency:

• Minimizing Drag: Excessive head lifting, especially in freestyle, disrupts the body's streamline, increasing frontal drag. Proper rotational breathing keeps the body flat and aligned with the direction of travel.
• Maintaining Body Position: The head is a heavy part of the body. Lifting it incorrectly can cause the hips to drop, increasing drag and making propulsion less efficient. A stable core and controlled head movement are essential.
• Rhythm and Timing: Breathing should be integrated seamlessly into the stroke cycle, becoming an extension of the movement rather than a separate, disruptive action. This maintains a consistent rhythm and power output.

Training for Improved Respiratory Efficiency

Swimmers can enhance their breathing capacity and technique through various training methods:

• Breath Control Drills:
  • Underwater Exhalation Drills: Practicing long, continuous exhalations underwater to improve lung emptying.
  • Bilateral Breathing Practice: Incorporating breathing on both sides into training sets.
  • Hypoxic Sets (with caution): Swimming longer distances or multiple laps on fewer breaths to adapt to higher CO2 levels. This should only be done under expert supervision due to risks of shallow water blackout.
• Cardiovascular Endurance Training: General aerobic fitness improves the body's ability to utilize oxygen and clear CO2 more efficiently.
• Core Strength: A strong core helps maintain a stable body position during head rotation, making breathing easier and more efficient.

Common Breathing Mistakes to Avoid

• Holding Breath: Holding breath while swimming increases CO2 buildup, leads to fatigue, and can cause a feeling of panic. Continuous exhalation underwater is paramount.
• Lifting Head Too High: This breaks the body's streamline, creates drag, and causes the hips to drop, leading to inefficient swimming.
• Gasping for Air: Taking short, shallow, panicked breaths indicates poor timing or insufficient exhalation. Focus on a relaxed, full exhale followed by a quick, deep inhale.
• Improper Timing: Breathing too early or too late in the stroke cycle can disrupt rhythm and propulsion.

In summary, "breathing underwater" for swimmers is a sophisticated skill that combines physiological adaptation with precise biomechanical execution. Mastering these techniques allows swimmers to sustain effort, maintain efficiency, and unlock their full potential in the water.