Fluid intake restores retinal blood flow early after exhaustive exercise in healthy subjects
It remains unclear whether rehydration restores retinal blood flow reduced by exhaustive exercise. We investigated the effect of fluid intake on retinal blood flow after exhaustive exercise.
Blood flow in the inferior (ITRA) and superior temporal retinal arterioles (STRA) was measured before and after incremental cycling exercise until exhaustion in 13 healthy males. After the exercise, the subjects rested without drinking (control condition: CON) or with drinking an electrolyte containing water (rehydrate condition: REH) and were followed up for a period of 120 min. To assess the hydration state, the body mass was measured, and venous blood samples were collected and plasma volume (PV) was calculated.
Body mass decreased in CON after the trial [− 1.1 ± 0.1% (mean ± SE), p < 0.05]. PV was lower in CON than in REH during recovery. The ITRA and STRA blood flows decreased immediately after exercise from the resting baseline (ITRA; − 23 ± 4% in REH and − 30 ± 4% in CON, p < 0.05). The ITRA blood flow recovered baseline level at 15 min of recovery in REH (− 9 ± 3%, p = 0.5), but it remained reduced in CON (-14 ± 3%, p < 0.05). The STRA blood flow was higher in REH than in CON at 15 min (2 ± 3 vs. − 5 ± 3%, p < 0.05).
The results of this study suggest that the reduction in retinal blood flow induced by exhaustive exercise can be recovered early by rehydration.
KeywordsOcular circulation Ocular blood flow Exercise Rehydration
Diastolic blood pressure
Internal carotid artery
Inferior temporal retinal arteriole
Mean arterial pressure
Ocular perfusion pressure
Arterial partial pressure of CO2
End-tidal partial pressure of CO2
End-tidal partial pressure of O2
Systolic blood pressure
Superior temporal retinal arteriole
This study was financially supported by Otsuka Pharmaceutical Factory Incorporated.
TI and KS conceived and designed research. TI, KS, NN, and KY conducted experiments. TI, NN, and KY analyzed data. TI, KS, and NH interpreted data. TI wrote the manuscript. TI, KS, and NH revised manuscript. All authors read and approved the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
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