Analysis of the diminished skin perfusion in elderly people by laser Doppler flowmetry

Clinical observations suggest an age-associated decline in skin perfusion but there are few quantitative in vivo data on skin perfusion at various ages. We studied skin perfusion of the dorsum of the foot by determining the capillary blood flow velocity (CBFV) expressed in millivolts (mV), using laser Doppler flowmetry, in ten young and 12 elderly men. Our data revealed that, at 32 degrees C skin temperature, the CBFV oscillations (vasomotions) are of higher median amplitude in young people than in elderly subjects: 9.4 mV (95% CI, 8.8-10.0 mV) and 4.6 mV (95% CI, 4.1-7.4 mV), respectively (p less than 0.05). The vasomotion frequency was similar in both age groups. At 44 degrees C skin temperature, the median CBFV peak in the young was 163 mV (95% CI, 128-192 mV), as opposed to 102 mV (95% CI, 92-124 mV) in the aged subjects (p less than 0.0005). The median increment in CBFV, driven by every heart beat, was also higher in the young age group: 86 mV (95% CI, 76.4-96.0 mV) compared with the elderly group: 63 mV (95% CI, 50-72 mV, p less than 0.005). Considering the fact that the magnitude but not the pattern of skin perfusion varied between the two groups, we conclude that ageing is associated with loss of capillary plexus functional units, and therefore the skin perfusion is lower in aged people.