The I/D ACE gene polymorphism was investigated as described 2 and confirmed by means of a second PCR amplification that selectively detects the I allele. 14 DD, homozygotes for the deletion allele; II, homozygotes for the insertion allele; ID, heterozygotes. #w 2 =7.238, exact P=0.03 for genotype frequencies in all kayakers vs all aerobic athletes. §w 2 =6.755, exact P=0.03 for genotype frequencies in aerobic Olympic athletes vs healthy population. *w 2 =5.867, exact P=0.05 for genotype frequencies in Olympic kayakers vs Olympic aerobic athletes.