Bunn, J. A., Key, M. A., & Eschbach, L. C. (2013). Assessment of the effects of controlled frequency breathing on lactate levels in swimming. Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 540.

"It has been suggested that reducing the breathing rate in a swimming race may lower the lactate production in the body, which may translate to improved performance."

This study assessed differences in post-swim blood lactate levels, heart rate, and time to completion of a maximal 100-yard freestyle swim in normal breathing and controlled-frequency breathing conditions. Division 1 female swimmers (N = 21) completed a 12-minute Cooper Swim Test, and two testing sessions consisting of a 500-yard warm-up followed by either the normal breathing or controlled-frequency breathing 100-yard all-out swim trial. The condition of the trial was randomly assigned. Ss breathed approximately every 2-4 strokes in the normal breathing trial, and breathed every seven strokes in the controlled-frequency breathing trial. Blood samples were taken from the earlobe at rest and 0, 1.5, 3, and 5 minutes after each 100-yard trial. Heart rate was measured at rest and immediately after completion of the exercise bout. Stroke rate, distance per cycle, velocity, splits, and finish time were calculated for all Ss.

There were no significant differences between breathing conditions on blood lactate levels post-swim at time 0 minute, 1.5 minutes, 3 minutes, or 5 minutes. Also, there were no differences in velocity, stroke rate, distance per cycle, or recorded time. However, post-exercise heart rate was significantly higher in the normal breathing trial when compared to the controlled-frequency breathing trial. The time difference between normal breathing (60.23 ± 2.44 s) and controlled-frequency breathing (61.36 ± 2.83 s) trials was not statistically significant but is important for a 100-yard swim.

Implication. Oxygen deprivation appears to have no significant immediate effect on blood lactate levels after high-intensity swimming races. The heart rate difference between the controlled-frequency breathing and normal breathing swims could be explained by the decrease in ventilation produced by the controlled-frequency breathing swim which would cause the heart rate to slow even during exercise.

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