FOREARM COMPOSITION CONTRIBUTES TO DIFFERENCES IN REACTIVE HYPEREMIA BETWEEN HEALTHY-MEN AND WOMEN

Background Post-ischaemic reactive hyperaemia in the forearm has been suggested as a marker of resistance Vessel function. The contribution of forearm composition to the kinetics of reactive hyperaemia is large ly unknown. The body composition of men and women differs in that wome n have a higher body fat content and less lean body mass. Methods In t he present study, we investigated whether the kinetics of reactive hyp eraemia in the forearm in 14 healthy subjects (seven men and seven wom en) show gender-specific differences and whether forearm composition c ontributes to such differences. Results Peak reactive hyperaemic flow as well as 1-min-flow debt repayment (measured by venous occlusion ple thysmography) were significantly higher in male than in female study p articipants. This difference was explained to > 60% by gender-specific differences in forearm relative muscle mass (as determined by magneti c resonance imaging). The half-life of the reactive hyperaemic respons e, on the other hand, was not different between men and women and did not show an association with forearm muscle. Conclusion Our results de monstrate that forearm composition must be considered if peak reactive hyperaemia or flow debt repayment is used as a target, and that dynam ic measurements of the reactive hyperaemic process are more suitable t o describe the function of resistance arteries than single-point obser vations.