title: The effects of diet on muscle pH and metabolism during high intensity exercise.
abstract: Five healthy male subjects exercised for 3 min at a workload equivalent to 100% VO2max on two separate occasions. Each exercise test was performed on an electrically braked cycle ergometer after a four-day period of dietary manipulation. During each of these periods subjects consumed either a low carbohydrate (3 +/- 0%, mean +/- SD), high fat (73 +/- 2%), high protein (24 +/- 3%) diet (FP) or a high carbohydrate (82 +/- 1%), low fat (8 +/- 1%) low protein (10 +/- 1%) diet (CHO). The diets were isoenergetic and were assigned in a randomised manner. Muscle biopsy samples (Vastus lateralis) were taken at rest prior to dietary manipulation, immediately prior to exercise and immediately post-exercise for measurement of pH, glycogen, glucose 6-phosphate, fructose 1,6-diphosphate, triose phosphates, lactate and glutamine content. Blood acid-base status and selected metabolites were measured in arterialised venous samples at rest prior to dietary manipulation, immediately prior to exercise and at pre-determined intervals during the post-exercise period. There was no differences between the two treatments in blood acid-base status at rest prior to dietary manipulation; immediately prior to exercise plasma pH (p less than 0.01), blood PCO2 (p less than 0.01), plasma bicarbonate (p less than 0.001) and blood base-excess (p less than 0.001) values were all lower on the FP treatment. There were no major differences in blood acid-base variables between the two diets during the post-exercise period.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Environmental and Occupational Medicine, University Medical School, Aberdeen, Scotland.
authors.forename: P L
authors.initials: PL
authors.lastname: Greenhaff
authors.forename: M
authors.initials: M
authors.lastname: Gleeson
authors.forename: R J
authors.initials: RJ
authors.lastname: Maughan
mesh_terms: D000136:Acid-Base Equilibrium; D000328:Adult; D001835:Body Weight; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D009132:Muscles / Q000378:metabolism*; D005082:Physical Exertion
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins