The 2019 publication investigated the effects of intensive running training on the pH value. Nine athletes completed sprint training under either hypoxic (oxygen deficiency) or normoxic (normal oxygen supply) conditions. The intensive interval endurance exercises consisted of 10 three-minute runs at 90% maximum oxygen intake alternating with 60-second intensity breaks (lower intensity runs at 50% of maximum oxygen intake). Venous blood was taken from the subjects before the training session and during afterloading. It was shown that endurance training under moderate hypoxia (e.g. during classical altitude training) led to acidification of the blood. The running speed of these subjects was clearly below that of those running under normoxic conditions. Endurance training under hypoxic conditions thus led to a temporary shift in the blood pH and thus high metabolic stress.
A 2017 review examined the trend of maximizing athletic performance through an alkaline-rich diet. Intensive training can lead to a temporary decrease in pH. An acidic muscle environment affects performance and contributes to fatigue. The 10 studies included in the review show that an alkaline diet can support performance under maximum effort. The authors hope to see further research on the subject because the few studies available to date had been conducted exclusively using an ergometer or treadmill and had predominantly involved male subjects. Nevertheless, the review concluded that an alkaline-rich diet is recommended for athletes of all ages because an alkaline-based diet (especially vegetables and fruit) is definitely beneficial for general health.
References:
Sumi, D. et al. 2019. The Effects of Endurance Exercise in Hypoxia on Acid-Base Balance, Potassium Kinetics, and Exogenous Glucose Oxidation. Front Physiol. 10:504.
Applegate, C. et al. 2017. Influence of Dietary Acid Load on Exercise Performance. Int J Sport Nutr Exerc Metab. 27(3):213–9.
