Effects of an Alkalizing or Acidizing Diet on High-Intensity Exercise Performance under Normoxic and Hypoxic Conditions in Physically Active Adults: A Randomized, Crossover Trial

Abstract

Pre-alkalization caused by dietary supplements such as sodium bicarbonate improves anaerobic exercise performance. However, the influence of a base-forming nutrition on anaerobic performance in hypoxia remains unknown. Herein, we investigated the effects of an alkalizing or acidizing diet on high-intensity performance and associated metabolic parameters in normoxia and hypoxia. In a randomized crossover design, 15 participants (24.5 ± 3.9 years old) performed two trials following four days of either an alkalizing (BASE) or an acidizing (ACID) diet in normoxia. Subsequently, participants performed two trials (BASE; ACID) after 12 h of normobaric hypoxic exposure. Anaerobic exercise performance was assessed using the portable tethered sprint running (PTSR) test. PTSR assessed overall peak force, mean force, and fatigue index. Blood lactate levels, blood gas parameters, heart rate, and rate of perceived exertion were assessed post-PTSR. Urinary pH was analyzed daily. There were no differences between BASE and ACID conditions for any of the PTSR-related parameters. However, urinary pH, blood pH, blood bicarbonate concentration, and base excess were significantly higher in BASE compared with ACID (p < 0.001). These findings show a diet-induced increase in blood buffer capacity, represented by blood bicarbonate concentration and base excess. However, diet-induced metabolic changes did not improve PTSR-related anaerobic performance.

A comparison of dietary acid load between team, endurance, and strength sports

“…They 8 also showed that the alkaline diet improved the buffering capacity in blood and muscle. However, when the same experimental design was applied under hypoxic conditions, it did not improve sprint performance 12 . In the literature, although there is no consensus on the effect of PRAL on exercise performance, it is assumed that vegetarian diets, an example of alkaline nutrition, could improve exercise performance by enhancing antioxidant capacity and the replenishment of glycogen stores, as well as by reducing body weight, body fat, blood pressure, and inflammation 13 .…”

“…Although PRAL studies are mainly focused on kidney patients and diabetic individuals 2 , studies in athletes have also recently begun to be published in the literature 8,9,10,11,12 . A limited number of studies conducted with athletes have focused on the effects of PRAL on aerobic and anaerobic performance as well as on running economy.…”

“…Although there are currently few studies on the performance effects of alkaline nutrition in the literature 8,9,10,11,12 , it is likely that the positive effects of this nutritional form will be mentioned frequently in the future. On the other hand, it is known that athletes in different sport branches naturally consume certain foods more frequently, in accordance with the physiological demands of that particular sport.…”

The association between dietary acid load with cardiometabolic risk factors and inflammatory markers amongst elderly men: A cross‐sectional study

“…In one study, fruits and grains but note vegetables and protein were associated with NAE 14 . A recent trial showed that alkaline supplementation improved systemic and tissue acid–base in healthy elderly 15 . During the digestion process, the stomach wall excretes hydrogen ions, the pancreas secretes alkali and the digestive tract absorbs sulfur amino acids 16 .…”

Effect of sodium bicarbonate contribution on energy metabolism during exercise: a systematic review and meta-analysis

“…There are some studies showing that NaHCO 3 can change the content of blood lactate (BLa), HCO 3 − , pH and BE [7][8][9][10] during anaerobic-based exercise. Although those parameters are affected by ingesting NaHCO 3 , the change of anaerobic metabolism systems (AnMS) is different.…”