Introduction: Recent data indicate that the insertion/deletion polymorphism of the angiotensin converting enzyme (ACE) gene may be one of biological factors controlling the physical fitness in sport activities. In selected groups of sportsmen of endurance character (e.g., long-distance runners, oarsmen/oarswomen and mountain climbers) there was a positive association between allele I of ACE gene with the sport performance. Objective: The aim of the work was to evaluate aerobic and anaerobic capacity of the organism of the sportsmen/sportswomen during the load tests in relation to genotype I/D of the ACE gene. Material and methods: The study included 36 healthy young individuals at the age of 19 to 25 years (mean age 21.77 ± 2.72 years), who reached top sport performance. Each of them was subjected to the load tests with spiroergometric examination on bicycle ergometer with continually increasing load intensity to determine aerobic capacity of the organism as also a 30-second test on bicycle ergometer at maximum effort with constant frequency of 100 revolutions per minute to characterize anaerobic capacity of the organism. At the same time the authors examined I/D polymorphism of ACE gene and genotypes obtained in this way were correlated with the results of the functional tests. Results: In the selective group of sportsmen the authors observed a higher frequency of the I allele as well as homozygous individuals with I/I genotype in comparison with a common population (P < 0.01). For the sake of evaluation of the results the sportsmen were divided into three groups in relation to ACE genotype (I/I group, I/D group and D/D group, respectively). There have been statistically significant differences 1) between the I/I and D/D groups in heart rate during anaerobic threshold (P < 0.01), in the maximum oxygen consumption (P < 0.05), in the fatigue index (P < 0.01) and the percentage of aerobic capacity in comparison with common population (P < 0.01). 2) There was a significant difference between the I/D and D/D group in heart rate in anaerobic threshold (P < 0.05), inmaximum oxygen consumption (P < 0.05) and in the fatigue index (P < 0.01). 3) Moreover, there was a significant difference between the group I/I and I/D in the heart rate in the anaerobic threshold (P < 0.05) and in the percentage of aerobic capacity as compared to common population (P < 0.01). Conclusion: The results revealed a significantly better performance in the sportsmen with genotype containing allele I. The results obtained support the hypothesis on an association between endurance sport performance and I/D polymorphism of the ACE gene.

        Key words: genetic predisposition, I/D polymorphism of the gene for angiotensin converting enzyme (ACE), physical load, sporting performance