Impact of exercise on retinal microvascular regulation measured by dynamic vessel analysis in healthy individuals

We assessed the acute impact of physical exercise on the retinal vessel diameter and the regulation of vasoconstriction and vasodilatation owing to flicker that has never been examined before. Forty young (mean age 24 years) healthy subjects (26 women and 14 men) had retinal examinations with dynamic vessel analysis prior and after (0.5, 1.5 and 2.5 h) intense exercise of 20 min. The measurements were always taken on continuous same eye, each with a 350-s permanent dynamic vascular analysis including three cycles of 20 s with 12.5-Hz flicker provocation of the retinal vessel analyser system (RVA) device. Blood pressure values were measured before and after the dynamic vessel analysis with a portable, automatic blood pressure monitor. Dynamic vessel analysis revealed that exercise had a substantial quickly and long-lasting effect on arterial and venous diameter (F = 30.38 and 35.85, P < 0.001) and arterial dilatation owing to flicker (F = 10.67, P < 0.005). The effect of flicker on arterial constriction was not significant for all time periods (F = 0.26). Friedman test revealed that arterial constriction to flicker was significantly increased at 30 and 90 min (χ(2) = 43.3 and 49.2, P < 0.001). Exercise had a significant effect on venous constriction and dilatation owing to flicker (F = 11.14, P < 0.001, F = 3.77, P < 0.05). Our results demonstrate that the expected impact of exercise can be accurately assessed with the RVA. We therefore suggest that the RVA is a valid instrument to assess early structural and functional alterations in the retinal vascular system.