Effects of dynamic exercise and its intensity on ocular blood flow in humans

Abstract

Visual performance is impaired when the ocular blood flow decreases, indicating that ocular blood flow plays a role in maintaining visual performance during exercise. We examined the ocular blood flow response to incremental cycling exercise to test the hypothesis that ocular blood flow is relatively stable during dynamic exercise because of its autoregulatory nature. The blood flow in the inferior and superior temporal retinal arterioles (ITRA and STRA, respectively) and retinal and choroidal vessels (RCV), mean arterial pressure, and heart rate (HR) were measured at rest and during leg cycling in nine young and healthy subjects (26 ± 5 years, mean ± SD). Ocular blood flow was measured by laser speckle flowmetry. The exercise intensity was incremented by 30 W every 3 min until the subject was unable to maintain a position appropriate for measuring ocular blood flow. Blood flow data obtained during cycling exercise were categorized based on HR as follows: <100, 100-120, and >120 bpm. Blood flow in the RCV increased with the exercise intensity: by 16 ± 8, 32 ± 13, and 40 ± 19% from baseline, respectively. However, blood flow and vascular conductance in the ITRA and STRA did not change significantly with exercise. These findings demonstrate for the first time that ocular blood flow increases in the retina and choroid, but not in the arterioles, with increasing exercise intensity during dynamic exercise.

Inner ocular blood flow response to exercise in healthy humans

“…Consistent with this observation, the authors also reported that choroidal blood flow increased concomitantly with an increase in mean arterial pressure (MAP) during incremental cycling exercise (Fig. 2) 12) . These findings suggested that inner ocular circulation is not constant during exercise, and that its blood flow is reflected by changes in perfusion pressure.…”

“…Retinal blood flow was maintained during submaximal dynamic exercise (Fig. 2) 12) . Choroidal blood flow also kept a constant value during low intensity exercise (< 100 bpm); however, it increased significantly during mild-to-moderate intensity exercise (100-140 bpm) accompanied by an increase in MAP 12) .…”

“…2) 12) . Choroidal blood flow also kept a constant value during low intensity exercise (< 100 bpm); however, it increased significantly during mild-to-moderate intensity exercise (100-140 bpm) accompanied by an increase in MAP 12) . During exhaustive exercise, choroidal blood flow decreased to almost baseline, whereas retinal blood flow was less than the resting baseline, despite an increase in MAP (Fig.…”

Blood flow in non-muscle tissues and organs during exercise: Nature of splanchnic and ocular circulation

“…One study found no change in the retinal circulation during either the cold pressor test or handgrip exercise, indirectly suggesting the existence of autoregulation 48) . Consistent with the presence of autoregulation, choroidal flow did not change during submaximal dynamic exercise even where there was a pressor response 45,46) . The choroidal flow increased in these studies, and hence autoregulation seems to be present in the retinal circulation, but not in the choroidal circulation.…”

“…Thus, eye functionality is too complex for it to be studied during exercise, although are shown compared to heart rate during cycling exercise. Hayashi et al 45) some researchers have attempted to characterize neurovascular coupling during dynamic exercise 59) . Research into eye function during exercise has really only just begun from the viewpoint of circulatory changes.…”