EFFECT OF CHOLINE SUPPLEMENTATION ON FATIGUE IN TRAINED CYCLISTS

The availability of choline, the precurser of the neurotransmitter, ac etylcholine, in the diet is sufficient to provide the body's requireme nts under normal conditions. However, preliminary evidence indicates t hat depletion of choline may limit performance, while oral supplementa tion may delay fatigue during prolonged efforts. A double-blind cross- over design was used to determine the relationship between plasma chol ine and fatigue during supramaximal brief and submaximal prolonged act ivities. Twenty male cyclists (ages 23-29) with maximal aerobic power (VO2max) between 58 and 81 ml . min(-1). kg(-1) were randomly divided into BRIEF (N = 10) and PROLONGED (N = 10) groups. One hour after drin king a beverage with or without choline bitartrate (2.43 g), cyclists began riding at a power output equivalent to approximately 150% (BRIEF ) and 70% (PROLONGED) of VO2max at a cadence of 80-90 rpm. Time to exh austion, indirect calorimetry and serum choline, lactate, and glucose were measured. Increases in choline levels of 37 and 52% were seen wit hin one hour of ingestion for BRIEF and PROLONGED groups, respectively . Neither group depleted choline during exercise under the choline or placebo conditions. Fatigue times and work performed under either test condition for the BRIEF or PROLONGED groups were similar. Consequentl y, trained cyclists do not deplete choline during supramaximal brief o r prolonged submaximal exercise, nor do they benefit from choline supp lementation to delay fatigue under these conditions.