McMaster, W. C., Stoddard, T., & Duncan, W. (1989). Enhancement of blood lactate clearance following maximal swimming. The American Journal of Sports Medicine, 17, 472-476.

The value of warm-down swims for assisting in the clearance of post-exercise blood lactate clearance was assessed. Six swimmers (F = 3, M = 3) swam for 15 min after a maximum swim under three different pace conditions: 55%, 65%, and 75% of maximum. These levels of swimming speed required exercise that was purely endurance in nature (below the anaerobic threshold).

It was found that such cool down swims return lactate levels to near resting values (<2 mM/L) in a 15 min period. There was no difference between any of the conditions although all swimmers preferred the 65% velocity.

The mechanism for accelerated lactate clearance includes efflux of lactate from muscle to the blood, local blood flow, and uptake by the liver, skeletal muscle, and heart. The biochemical changes in lactate are debatable. Some theorize that it is converted to carbon dioxide and water while others contend that some is resynthesized to glycogen in the local tissues.

Implication. Performing a 15 min cool down swim clears lactate from the blood faster than passive resting. It is recommended that swimmers adopt this practice as an habitual activity for both training and competitions. It is particularly important for multiple event meets. At training it can be used to accelerate recovery between demanding sets of interval and repetition training.

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