Blood lipids of young distance runners: distribution and inter-relationships among training volume, peak oxygen consumption, and body fatness

This study describes the distribution of blood lipid concentrations and exa mines relationships among training volume (TV, kilometers per week), peak o xygen consumption ((V)over dotO(2peak)), body fatness, and blood lipid conc entrations in 48 male and 22 female distance runners, aged 10-19 years. Com parisons were made to a current reference sample and clinical cut-off point s. Relationships were assessed by partial correlations allowing for age and sexual maturity. Compared to reference median values, mean concentrations of total cholesterol (P=0.07) and low density lipoprotein-cholesterol (P<0. 005) were higher, while high density lipoprotein-cholesterol (HDL-C; P=0.24 ) was comparable in male distance runners. Blood lipid concentrations in fe male distance runners were comparable to reference median values. Although some subjects had dyslipidemic values, most possessed clinically normal con centrations of blood lipids. The TV was weakly correlated with blood lipid concentrations, but may have been indirectly related with HDL-C through its relationship with (V)over dotO(2peak) in males runners (r=0.32). In female runners, correlations between sum of skinfolds' (SSF), the trunk-to-extrem ity ratio (TER) and blood lipid concentrations were low (r=0.16 to -0.27), with one exception (TER and HDL-C, r=-0.60). The most consistent relationsh ips existed among TV, (V)over dotO(2peak), SSF, and HDL-C with partial corr elations ranging from low (r=0.10 TV) to moderate (r=0.37 SSF, r=0.41 (V)ov er dotO(2peak)). The correlation between (V)over dotO(2peak) and HDL-C rema ined significant after allowing for age and SSF, while the partial correlat ion between SSF and HDL-C, allowing for age and (V)over dotO(2peak), was re duced and not significant (r=-0.19, P=0.20). In female runners, the correla tion between (V)over dotO(2peak) and HDL-C was r=0.32, whereas the partial correlation between SSF and HDLC, allowing for age and (V)over dotO(2peak), was r=0.00. Blood lipid concentrations of young male distance runners were not, on average, different to the general population of the youth of the U nited States. The young distance runners showed considerable heterogeneity in blood lipid phenotypes, including dyslipidemic values. The results highl ight the complex relationships among TV, (V)over dotO(2peak), body fat and HDL-C, and indicate the unique contribution of (V)over dotO(2peak) as an im portant predictor of HDL-C in young distance runners.