Interindividual Variation in Cardiorespiratory Fitness: A Candidate Gene Study in Han Chinese People

Cardiorespiratory fitness, as assessed through peak oxygen uptake (VO_2peak), is a powerful health indicator. We aimed to evaluate the influence of several candidate causal genetic variants on VO_2peak level in untrained Han Chinese people. A total of 1009 participants (566 women; age [mean ± SD] 40 ± 14 years, VO_2peak 29.9 ± 7.1 mL/kg/min) performed a maximal incremental cycling test for VO_2peak determination. Genomic DNA was extracted from peripheral whole blood, and genotyping analysis was performed on 125 gene variants. Using age, sex, and body mass as covariates, and setting a stringent threshold p-value of 0.0004, only one single nucleotide polymorphism (SNP), located in the gene encoding angiotensin-converting enzyme (rs4295), was associated with VO_2peak (β = 0.87; p < 2.9 × 10^-4). Stepwise multiple regression analysis identified a panel of three SNPs (rs4295 = 1.1%, angiotensin II receptor type 1 rs275652 = 0.6%, and myostatin rs7570532 = 0.5%) that together accounted for 2.2% (p = 0.0007) of the interindividual variance in VO_2peak. Participants carrying six 'favorable' alleles had a higher VO_2peak (32.3 ± 8.1 mL/kg/min) than those carrying only one favorable allele (24.6 ± 5.2 mL/kg/min, p < 0.0001). In summary, VO_2peak at the pre-trained state is partly influenced by several polymorphic variations in candidate genes, but they represent a minor portion of the variance.