Doctoral defence: Ivi Vaher "The effects of acute sodium citrate supplementation on metabolism and 5000 m running performance in a trained young men"

On November 6 Ivi Vaher will defend her doctoral thesis “The effects of acute sodium citrate supplementation on metabolism and 5000 m running performance in a trained young men".

Supervisor:
Professor Vahur Ööpik, University of Tartu

Opponent:
Professor Lars Mc Naughton, Edge Hill University (England)

Summary:
During high-intensity exercise, ATP is rapidly broken down and regenerated through glycolytic phosphorylation. This process leads to the accumulation of hydrogen ions, which increases acidity in muscle cells and the body’s internal environment. This rise in acidity is a key factor contributing to the rapid onset and progression of fatigue. One strategy to mitigate acidosis—and thereby alleviate fatigue and enhance performance—is to increase the buffering capacity of the body’s systems prior to exertion.

Studies dating back to the early 20th century have shown that the buffering capacity of the body can be enhanced through the administration of sodium bicarbonate or sodium citrate. When taken as dietary supplements, these substances induce metabolic alkalosis, characterized by an increase in blood pH and bicarbonate ion concentration. Sodium citrate, in particular, has also been observed to increase water retention and plasma volume, which may improve endurance performance.

The aim of the studies conducted within the framework of this doctoral thesis was to evaluate the effects of sodium citrate supplementation on metabolism and performance during a 5000-meter run under different environmental conditions: in a laboratory setting with moderate and high temperatures, and in a simulated competition scenario at an outdoor stadium with normal ambient temperature. A total of 43 trained male endurance athletes participated in the studies. Sodium citrate or placebo was administered prior to the run in different forms (aqueous solution or encapsulated). All three studies followed a randomized, double-blind, crossover design.

The results showed that sodium citrate, compared to placebo, significantly improved 5000 meter run times only in the laboratory environment with moderate temperature. In the high-temperature laboratory setting and in the simulated competition at the outdoor stadium, sodium citrate had no effect on performance. Sodium citrate administration induced metabolic alkalosis, evidenced by increased blood pH and bicarbonate ion concentration, which facilitated lactate efflux from working muscles into the bloodstream. Sodium citrate also increased water retention and plasma volume prior to the run; however, changes in plasma volume during the run did not differ between the sodium citrate and placebo conditions. No differences were observed between the groups in terms of subjective fatigue, heat perception, or heart rate.

In conclusion, the studies indicate that administering sodium citrate at a dose of 500 mg per kilogram of body weight prior to a 5000 meter run leads to water retention and increased plasma volume before the start, and induces metabolic alkalosis that promotes lactate clearance from working muscles during exercise. These physiological changes may enhance performance in trained athletes under moderately warm, well-controlled laboratory conditions, but are insufficient to elicit similar benefits in high-temperature laboratory settings or in simulated competition scenarios at outdoor stadiums with moderate temperatures.