PMID- 8861677
OWN - NLM
STAT- MEDLINE
DCOM- 19970527
LR  - 20190830
IS  - 0301-5548 (Print)
IS  - 0301-5548 (Linking)
VI  - 73
IP  - 1-2
DP  - 1996
TI  - The acute reversal of a diet-induced metabolic acidosis does not restore 
      endurance capacity during high-intensity exercise in man.
PG  - 105-12
AB  - The present experiment was designed to investigate whether a diet-induced 
      metabolic acidosis was a major factor in the earlier onset of fatigue during 
      high-intensity exercise. Six healthy males cycled to exhaustion at a workload 
      equivalent to 95 percent of maximum oxygen uptake on four separate occasions. 
      Exercise tests were performed after an overnight fast and each test was preceded 
      by one of four experimental conditions. Two experimental diets were designed, 
      either to replicate each subject's own normal diet [N diet, mean (SD) daily 
      energy intake (E) = 13 (0.7) MJ, 14.5 (0.8) percent protein (Pro), 37.5 (2.2) 
      percent fat (Fat) and 47.5 (2.1) percent carbohydrate (CHO)], or a 
      low-carbohydrate diet [E = 12.6 (0.8) MJ, 33.6 (1.3) percent Pro, 64.4 (1.5) 
      percent Fat and 2.2 (0.4) percent CHO]. These diets were prepared and consumed 
      within the department over a 3-day period. Over a 3-period prior to the exercise 
      trial subjects ingested either NaHCO(3) or CaCO(3) (3.6 and 3.0 mmol*kg body 
      mass), thus giving four experimental conditions: N diet and treatment, N diet and 
      placebo, low-CHO diet and treatment and low-CHO diet and placebo. Treatments were 
      assigned using a randomised protocol. Arterialised venous blood samples were 
      taken for the determination of acid-base status and metabolite concentrations at 
      rest prior to exercise and at intervals for 30 min following exhaustion. 
      Consumption of the low-CHO diet induced a mild metabolic acidosis which was 
      reversed by the ingestion of NaHCO(3). Blood pH, bicarbonate (HCO-(3)) and base 
      excess (BE) were higher following NaHCO(3) ingestion after the normal diet than 
      all of the other experimental conditions (P <0.01). Exercise time following the 
      low-CHO diet was less than on the normal diet conditions (P <0.05): bicarbonate 
      ingestion had no effect on exercise time on either of the diet conditions. 
      Post-exercise blood pH, HCO-(3); and BE were higher following the ingestion of 
      NaHCO(3) irrespective of the pre-exercise diet (P <0.05). Blood lactate 
      concentration was higher 2 min after exercise following the N diet with NaHCO(3) 
      when compared to the low-CHO diets with either NaHCO(3) or placebo (P <0.05). 
      Plasma ammonia accumulation was not significantly different between experimental 
      conditions. These data confirm previous data showing that the ingestion of a 
      low-CHO diet reduces the capacity to perform high-intensity exercise, but it 
      appears that the metabolic acidosis induced by the low-CHO diet is not the cause 
      of the reduced exercise capacity observed during high-intensity exercise under 
      these conditions.
FAU - Ball, D
AU  - Ball D
AD  - Department of Enviromental and Occupational Medicine, University Medical School, 
      Foresterhill, Aberdeen, UK.
FAU - Greenhaff, P L
AU  - Greenhaff PL
FAU - Maughan, R J
AU  - Maughan RJ
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Randomized Controlled Trial
PT  - Research Support, Non-U.S. Gov't
PL  - Germany
TA  - Eur J Appl Physiol Occup Physiol
JT  - European journal of applied physiology and occupational physiology
JID - 0410266
RN  - 0 (Dietary Carbohydrates)
RN  - 8MDF5V39QO (Sodium Bicarbonate)
SB  - IM
MH  - Acid-Base Equilibrium
MH  - Acidosis/*drug therapy/*etiology/metabolism
MH  - Adult
MH  - Blood/metabolism
MH  - Dietary Carbohydrates/*administration & dosage
MH  - *Exercise
MH  - Humans
MH  - Male
MH  - *Physical Endurance
MH  - Sodium Bicarbonate/*therapeutic use
MH  - Time Factors
EDAT- 1996/01/01 00:00
MHDA- 1996/01/01 00:01
CRDT- 1996/01/01 00:00
PHST- 1996/01/01 00:00 [pubmed]
PHST- 1996/01/01 00:01 [medline]
PHST- 1996/01/01 00:00 [entrez]
AID - 10.1007/BF00262817 [doi]
PST - ppublish
SO  - Eur J Appl Physiol Occup Physiol. 1996;73(1-2):105-12. doi: 10.1007/BF00262817.