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Ocular circulatory responses to exhaustive exercise in humans
Tsukasa Ikemura1, Naoyuki Hayashi
1Graduate School of Human-Environment Studies, Kyushu University, Kasuga, Fukuoka, 816-8580, Japan.
Intense exercise may decrease ocular blood flow due to hyperventilation. While submaximal exercise boosts ocular blood flow, exhaustion leads to reduced blood flow in retinal and choroidal vasculature.
Area of Science:
- Ophthalmology
- Exercise Physiology
- Cardiovascular Science
Background:
- Submaximal exercise has been shown to increase ocular blood flow.
- The effect of exhaustive exercise on ocular blood flow remains unclear.
- Hyperventilation during exhaustion may lead to decreased PaCO(2), potentially reducing ocular blood flow.
Purpose of the Study:
- To investigate the impact of exhaustive dynamic exercise on ocular blood flow.
- To test the hypothesis that ocular blood flow decreases at exhaustion due to hypocapnia.
Main Methods:
- 12 healthy males performed cycle ergometer exercise until exhaustion.
- Ocular blood flow (retinal and choroidal vasculature, retinal arterioles), blood pressure, and respiratory parameters were measured.
- Laser-speckle flowgraphy and calculations of ocular vascular conductance index (CI) were employed.
Main Results:
- Mean arterial pressure increased, while PaCO(2) decreased significantly at exhaustion.
- Ocular blood flow velocity increased initially but returned to baseline at exhaustion.
- Ocular vascular conductance index (CI) significantly decreased at exhaustion, indicating suppressed ocular blood flow.
Conclusions:
- Submaximal exercise increases ocular blood flow.
- Exhaustive exercise suppresses ocular blood flow, likely due to exercise-induced hypocapnia.
- Findings highlight the differential effects of exercise intensity on ocular perfusion.
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