Beasley, K. N., Lee, E. C., McDermott, B. P., Yamamoto, L. M., Emmanuel, H., Casa, D. J., Armsrong, L. E, Kraemer, W. J., & Maresh, C. M. (June 03, 2010). The effect of oral versus intravenous rehydration on circulating myoglobin and creatine kinase. Presentation 2294 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.

This study examined the effects of mode of rehydration on markers of muscle damage (myoglobin and creatine kinase) following intense exercise performed in the heat in healthy, active males (N = 11). Ss completed four experimental trials consisting of an exercise dehydration protocol (to -4% of baseline body mass), followed by a rehydration period (oral, intravenous, oral and intravenous combined, and ad libitum), and finishing with an intense exercise challenge that included treadmill running and sprinting and a box lifting protocol. During rehydration, Ss returned to -2% of baseline body mass unless completing the ad libitum trial during which they consumed fluids as thirst dictated. Myoglobin and creatine kinase were measured during euhydrated rest. Post-exercise blood was drawn at one and twenty-four hours post-exercise challenge for myoglobin and creatine kinase. Urine was collected during euhydrated rest and one-hour post-exercise challenge for measurement of myoglobin clearance.

Myoglobin concentrations increased significantly from pre- to post-exercise for intravenous, oral, oral and intravenous combined, and ad libitum treatments, but were not significantly different. Serum creatine kinase concentrations remained within the normal physiological range for all trials.

Implication. Despite previous research that indicated the benefit of ingesting fluids during exercise in order to attenuate muscle damage, there were no significant differences between the modes of rehydration on circulating myoglobin and creatine kinase.

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