Low intake or tissue concentrations of the n-6 PUFA, especially to the major n-6 PUFA linoleic acid (LA), and low exercise cardiac power (ECP) are both associated with CVD risk. However, associations of the n-6 PUFA with ECP are unknown. The aim of the present study was to explore cross-sectional associations of the serum total n-6 PUFA, LA, arachidonic acid (AA), γ-linolenic acid (GLA) and dihomo-γ-linolenic acid (DGLA) concentrations with ECP and its components. In total, 1685 men aged 42–60 years from the Kuopio Ischaemic Heart Disease Risk Factor Study and free of CVD were included. ANCOVA was used to examine the mean values of ECP (maximal oxygen uptake (VO2max)/maximal systolic blood pressure (SBP)) and its components in quartiles of the serum total and individual n-6 PUFA concentrations. After multivariable adjustments, higher serum total n-6 PUFA concentration was associated with higher ECP and VO2max (for ECP, the extreme-quartile difference was 0·77 ml/mmHg (95 % CI 0·38, 1·16, P for trend across quartiles < 0·001) and for VO2max 157 ml/min (95 % CI 85, 230, P for trend < 0·001), but not with maximal SBP. Similar associations were observed with serum LA concentration. Higher serum AA concentration was associated with higher ECP but not with VO2max or maximal SBP. The minor serum n-6 PUFA GLA and DGLA were associated with higher maximal SBP during exercise test and DGLA also with higher VO2max but neither with ECP. In conclusion, especially LA concentration was associated with higher ECP. This may provide one mechanism for the cardioprotective properties of, especially, LA.

When a human begins to move or locomote, the energetic demands of its skeletal muscles increase abruptly and the oxygen (O2) transport system responds to deliver increased amounts of O2 to the respiring mitochondria. It is intuitively reasonable that the rapidity with which O2 transport can be increased to and utilized by (VO2) the contracting muscles would be greater in those species with a higher maximal VO2 capacity (i.e., VO2max). This review explores the relationship between VO2max and VO2 dynamics or kinetics at across a range of species selected, in part, for their disparate VO2max capacities. In healthy humans there is compelling evidence that the speed of the VO2 kinetics at the onset of exercise is limited by an oxidative enzyme inertia within the exercising muscles rather than by VO2 delivery to those muscles. This appears true also for the horse and dog but possibly not for a certain species of frog. Whereas there is a significant correlation between VO2max and the speed of VO2 kinetics among different species, it is possible to identify species or individuals within a species that exhibit widely disparate mass-specific VO2max capacities but similar VO2 kinetics (i.e., superlative human athlete and horse).