Regulation of oxygen saturation in retinal blood vessels in response to dynamic exercise

Abstract

Purpose: To evaluate the impact of dynamic exercise on retinal vessel oxygen saturation in healthy individuals. Methods: Twenty-six healthy participants underwent moderate dynamic exercise (modified Master’s two step exercise). All subjects intraocular pressures (IOP), systolic and diastolic blood pressure (SBP and DBP), retinal vessel calibres and retinal arterial and venous oxygen saturation was measured at baseline, immediately following exercise and 15 minutes post exercise. Results: Moderate dynamic exercise increased systolic and diastolic blood pressures immediately post exercise (SBP: 116 (+/-13) mmHg to 150 (+/-21) mmHg; p<0.001 and DBP: 69 (+/-10) mmHg to 74 (+/-10); p<0.001) while IOP decreased by an average of 2 mmHg (baseline: 13 (+/-3) mmHg)) immediately post exercise (11 (+/-2) mmHg). Oxygen saturation in retinal arteries remained unchanged (baseline= 93 +/-8%; immediately post exercise=94 +/-9% and 15 minutes post exercise=96 +/-8%; p=0.069) but increased in retinal veins immediately post exercise and did not return to baseline values within 15 minutes post exercise (baseline=54 +/-12%; immediately post exercise=56 +/-15%; 15 minutes post exercise=57 +/-12%; p=0.036).  Conclusion: There is a mild increase in retinal venous oxygen saturation and a trend towards an increase in arterial saturation in otherwise healthy individuals following dynamic exercise.