Effects of carbohydrate and chromium ingestion during intermittent high-intensity exercise to fatigue.
OBJECTIVE
This study was designed to test the hypothesis that addition of chromium (Cr) to a carbohydrate-electrolyte drink would enhance the reported benefits of carbohydrate on exercise capacity during intermittent high-intensity shuttle running.


METHODS
Eight physically active men performed 3 exercise trials while ingesting 6% carbohydrate-electrolyte (CHO), CHO plus chromium picolinate (400 mg) (CHO + Cr+3), or placebo (P) using a double-blind, counterbalanced design. Each trial consisted of 5 3 15 min bouts of shuttle running (walk, sprint, and run at 95 and 55% of estimated VáO2max, separated by 3-min rest). This was followed by a fatigue test (running alternating 20-m lengths at 55 and 95% of estimated VáO2 until fatigue).


RESULTS
During the standardized shuttle running, blood glucose was higher with both CHO and CHO + Cr+3 than P. Plasma free fatty acid was higher in P than both CHO and CHO + Cr+3 at 75 min of exercise and at fatigue. In the fatigue test, subjects ran longer with both CHO and CHO + Cr+3 than P.


CONCLUSIONS
The data confirm an ergogenic benefit of ingesting CHO during exercise designed to imitate sports like basketball, soccer, and hockey, but do not support the hypothesis that the addition of Cr would enhance this effect.
Davis
J M
JM
Department of Exercise Science, School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
Welsh
R S
RS
Alerson
N A
NA
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002857:Chromium / Q000008:administration & dosage / Q000494:pharmacology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004311:Double-Blind Method; D004573:Electrolytes / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology*; D005221:Fatigue; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000187:drug effects*; D005082:Physical Exertion / Q000187:drug effects*; D013997:Time Factors
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004573:Electrolytes; D002857:Chromium