1.5 EFFECTS OF ACUTE BOUTS OF ENDURANCE EXERCISE ON RETINAL VESSEL DIAMETERS

Abstract

Objectives. Retinal vessel diameters are a valid tissue biomarker for cardiovascular risk assessment. We aimed to assess the acute effects of different exercise intensities on retinal vessel diameters, and whether these effects differ between seniors and young adults. Methods. In this cross-over study, 17 seniors (mean (SD) age 67 (5) years) and 15 young adults (mean (SD) age 26 (4) years) first performed a maximal treadmill test (MTT) followed by a submaximal 2-km treadmill test (SMTT) and a control condition in randomised order. We measured central retinal arteriolar (CRAE, μm) and venular (CRVE, μm) equivalent before as well as 5 (t5) and 40 (t40) minutes after exercise cessation using a Static Retinal Vessel Analyser. Results. Relative to the control condition, both MTT and SMTT led to a statistically significant dilatation in CRAE and CRVE. At t40, the dilatation was greater for MTT compared to SMTT (CRAE: 1.7 (95% CI −0.1, 3.6; P = 0.061); CRVE: 2.2 (95% CI 0.4, 4.1; P = 0.019)). In seniors, average CRAE and CRVE at t5 were higher for MTT compared to SMTT. In young adults, both parameters were lower for MTT compared to SMTT. The estimated difference between seniors and young adults in the cross-over difference comparing MTT and SMTT was 5.3 (95% CI 2.0, 8.5; P = 0.002) for CRAE and 4.1 (95% CI −0.4, 8.6; P = 0.076) for CRVE. Conclusions. Acute bouts of endurance exercise lead to an increase in retinal vessel diameters. The regulatory mechanisms following acute bouts of exercise may differ according to age.