The role of spleen and lung volumes in artistic swimming

Artistic swimming (AS) is a demanding sport that combines elements of strength, endurance, flexibility, and artistic expression. Athletes perform synchronized routines in the water, either solo, in duets, or in teams, accompanied by music. These routines last between two to four minutes and require increasingly higher levels of intensity, with approximately 50% of the time spent in apnea (breath-holding). To achieve this, swimmers must undergo extensive training not only in physical conditioning but also in improving their apnea performance.

At the elite level, training demands are exceptionally high, with athletes engaging in intensive and high-volume training programs averaging around 40 hours per week. These programs include strength and conditioning exercises, endurance work, and long hours in the pool perfecting synchronization and choreography. Properly regulating exercise intensity is crucial, as insufficient intensity may not induce the necessary physiological adaptations, while excessive intensity can lead to fatigue, overtraining, and even athlete dropouts.

In Sweden, artistic swimming remains a relatively uncommon sport, with only ten active clubs as of 2024. The country currently ranks 22nd in international AS standings, lagging behind more dominant nations. Despite this, Swedish AS athletes have reached the finals in junior and senior competitions at the European Championship level. Limited access to pools and financial constraints preventing full-time training may contribute to Sweden’s lower ranking, alongside potential issues related to training structure and optimization.

The evolving demands of artistic swimming have placed even emphasis on apnea, highlighting its crucial role in performance and endurance. in AS routines, increasing the periods in which athletes must hold their breath. The ability to sustain apnea is determined by three key factors: (1) the body’s total gas storage capacity in the lungs, blood, and tissues; (2) tolerance to hypoxia and hypercapnia, which depends on brain oxygen tolerance and CO2 buffering capacity; and (3) metabolic rate, which is influenced by work economy and physiological adaptations such as the diving response (characterized by bradycardia, reduced cardiac output, peripheral vasoconstriction, and increased blood pressure).

The human spleen plays a significant role in apnea performance, as it contracts during breath-holding and exercise, increasing circulation of hemoglobin and hematocrit. This enhances oxygen storage and buffering capacity, benefiting apnea duration. While spleen and lung volume have been extensively studied in freedivers, there is limited research on their impact on artistic swimmers.

This study aims to investigate the magnitude of spleen contraction and its hematological response during apnea in AS athletes. Additionally, it will compare spleen and lung volume (measured non-invasively) with individual scores in AS competitions. The hypothesis is that competition scores will positively correlate with spleen and lung volume, indicating that larger spleen and lung capacities may contribute to better performance. Beyond sports applications, understanding the effects of hypoxic exposure in AS athletes could also provide insights into medical conditions such as sleep apnea.