Effects of ageing and fitness on skin-microvessel vasodilator function in humans

Abstract

The impact of cardiopulmonaryfitness (V̇O2max) on the age-related decline in skin-microvessel vasodilator function has not been fully established and the inter-relationships among different measures of microvascular vasodilator function are unknown. We used laser Doppler flowmetry to assess relative changes in forearm skin blood flow to various stimuli in three groups of adults: young (n = 15; 27 ± 2 years), older sedentary (n = 14; 65 ± 6 years) and older fit (n = 15; 61 ± 5 years). Local-heating induced and post-occlusive hyperaemia responses were higher inthe young and olderfit groups compared tothe older sedentary group (P < 0.05) and were moderately correlated with V̇O2max in the pooled cohort of older adults (r = 0.49-0.58; P < 0.05). Peak hyperaemia responses to acetylcholine and sodium nitroprusside were higher in young compared to older sedentary adults (P < 0.05) and were not associated with V̇O 2max in older adults (P > 0.05). Associations among different measures of microvascular vasodilator function were generally moderate at best. In summary, the local heating and reactive hyperaemia data indicate that the age-related decline in skin-microvessel vasodilator function can be ameliorated through regular aerobic exercise training. As this is not supported by the iontophoresis data, we recommend that, when assessing microvascular function, the use of a single physiological or pharmacological stimulation coupledtolaser Doppler flowmetry shouldbeavoided. Finally, the moderate correlations between outcomes probably reflect the distinct mediators that are responsible for the vasodilator response to each test. © Springer-Verlag 2010.