Effect of carbohydrate intake during recovery from eccentric exercise on interleukin-6 and muscle-damage markers

The purpose of this investigation was to determine whether carbohydrate supplementation during the first 2 d postexercise recovery influenced the inflammation (IL-6, C-reactive protein [CRP], and cortisol) and muscle-damage responses. Eight participants performed a high-force eccentric elbow-flexion exercise to induce muscle soreness and inflammation and then consumed carbohydrate (0.25 g.kg(-1).h(-1)) or an equal volume of placebo during hours 0-12 and 24-36 postexercise in a double-blind, crossover protocol. Muscle soreness; midbrachial arm circumference; blood glucose, IL-6, CRP, cortisol, and creatine-kinase (CK) activity; and maximal force production were measured preexercise and 4, 8, 12, 24, 48, and 120 h postexercise. Plasma IL-6 increased, F(5) = 5.27, P < 0.05, 8 h postexercise, with no difference between carbohydrate and placebo conditions. Changes in muscle soreness, arm circumference, strength, and serum CK activity were consistent with small amounts of muscle damage and did not differ between conditions. The authors conclude that carbohydrate supplementation during recovery from soreness-inducing exercise does not influence the delayed IL-6 response temporally linked to inflammation or indications of muscle damage. Thus, increased carbohydrate consumption at levels consistent with recommendations for replenishing glycogen stores does not impair or promote the immune and muscle responses.