Journal of Sports Science and Medicine
Journal of Sports Science and Medicine
ISSN: 1303 - 2968   
Ios-APP Journal of Sports Science and Medicine
Androit-APP Journal of Sports Science and Medicine
©Journal of Sports Science and Medicine (2015) 14, 364 - 371

Research article
Effects of Dietary Acid Load on Exercise Metabolism and Anaerobic Exercise Performance
Susan L. Caciano1, Cynthia L. Inman1,2, Elizabeth E. Gockel-Blessing3, Edward P. Weiss1,4, 
Author Information
1 Department of Nutrition and Dietetics, Doisy College of Health Sciences, Saint Louis University, St. Louis, MO, USA
2 Department of Kinesiology and Health Education, Southern Illinois University, Edwardsville, IL, USA
3 Department of Clinical Laboratory Sciences, Doisy College of Health Sciences, Saint Louis University, St. Louis, MO, USA
4 Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA

Edward P. Weiss
✉ PhD, Department of Nutrition and Dietetics, 3437, Caroline Street, Saint Louis University, St. Louis, MO 63104, USA
Publish Date
Received: 27-11-2014
Accepted: 25-02-2015
Published (online): 01-06-2015
Share this article

Dietary acid load, quantified as the potential renal acid load (PRAL) of the diet, affects systemic pH and acid-base regulation. In a previous cross-sectional study, we reported that a low dietary PRAL (i.e. alkaline promoting diet) is associated with higher respiratory exchange ratio (RER) values during maximal exercise. The purpose of the present study was to confirm the previous findings with a short-term dietary intervention study. Additionally, we sought to determine if changes in PRAL affects submaximal exercise RER (as a reflection of substrate utilization) and anaerobic exercise performance. Subjects underwent a graded treadmill exercise test (GXT) to exhaustion and an anaerobic exercise performance test on two occasions, once after following a low-PRAL diet and on a separate occasion, after a high-PRAL diet. The diets were continued as long as needed to achieve an alkaline or acid fasted morning urine pH, respectively, with all being 4-9 days in duration. RER was measured during the GXT with indirect calorimetry. The anaerobic performance test was a running time-to-exhaustion test lasting 1-4 min. Maximal exercise RER was lower in the low-PRAL trial compared to the high-PRAL trial (1.10 ± 0.02 vs. 1.20 ± 0.05, p = 0.037). The low-PRAL diet also resulted in a 21% greater time to exhaustion during anaerobic exercise (2.56 ± 0.36 vs. 2.11 ± 0.31 sec, p = 0.044) and a strong tendency for lower RER values during submaximal exercise at 70% VO2max (0.88 ± 0.02 vs. 0.96 ± 0.04, p = 0.060). Contrary to our expectations, a short-term low-PRAL (alkaline promoting) diet resulted in lower RER values during maximal-intensity exercise. However, the low-PRAL diet also increased anaerobic exercise time to exhaustion and appears to have shifted submaximal exercise substrate utilization to favor lipid oxidation and spare carbohydrate, both of which would be considered favorable effects in the context of exercise performance.

Key words: Renal acid load, alkaline diet, substrate oxidation, respiratory exchange ratio

           Key Points
  • Short-term (4-9 days) changes in the acid or alkaline promoting qualities of the diet, quantified as potential renal acid load (PRAL), alter systemic pH, as evidenced in the present study by changes in fasted morning urine pH. Low-PRAL (alkaline promoting) diets are characterized by high intakes of vegetables and fruits with limited consumption of meats, cheeses, and grains while high-PRAL diets are characterized by the opposite dietary pattern.
  • An alkaline promoting (low-PRAL) diet increases anaerobic exercise performance, as evidenced by greater time-to-exhaustion during high-intensity treadmill running.
  • Preliminary evidence suggests that an alkaline promoting (low-PRAL) diet increases lipid oxidation and may have a carbohydrate-sparing effect during submaximal endurance exercise, although further studies are needed.
  • In contrast to what has been observed in response to habitual/long-term dietary patterns, a short-term low-PRAL diet does not increase maximal exercise respiratory exchange ratio and even appears to lower it. This suggests that short-term and long-term alterations in PRAL have different physiologic effects on this parameter.
Home Issues About Authors
Contact Current Editorial board Authors instructions
Email alerts In Press Mission For Reviewers
Archive Scope
Supplements Statistics
Most Read Articles
  Most Cited Articles
JSSM | Copyright 2001-2020 | All rights reserved. | LEGAL NOTICES | Publisher

It is forbidden the total or partial reproduction of this web site and the published materials, the treatment of its database, any kind of transition and for any means, either electronic, mechanic or other methods, without the previous written permission of the JSSM.

This work is licensed under a Creative Commons License Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.