Physiology

A Model Athlete

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Science  03 Mar 2000:
Vol. 287, Issue 5458, pp. 1557
DOI: 10.1126/science.287.5458.1557e

The “catch and release” angler will no doubt disagree with the assertion in the scientific literature that an exhaustively stressed fish requires up to 24 hours for metabolic recovery, as assessed by circulating lactate levels and replenishment of glycogen stores. Milligan et al. now resolve this discordance by reexamining the laboratory conditions of measurement. They find that the experimental system of allowing recovering rainbow trout to remain stationary actually serves to trigger a rise in cortisol levels, in contrast to placing the exercised fish within a swim flume for the duration of the recovery period. These swimming fish do not exhibit an increase in cortisol, and their lactate and glycogen levels return to pre-stress values within 2 hours, as does their blood pH. Thus, post-exercise activity—the “cool down” period—is beneficial and highly recommended.—GJC

J. Exp. Biol.203, 921 (2000).

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