Ocular circulatory responses to exhaustive exercise in humans

Tsukasa Ikemura, Naoyuki Hayashi

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

It is unclear whether exhaustive dynamic exercise increases ocular blood flow, although we have reported that submaximal exercise increases ocular blood flow. We hypothesized that ocular blood flow decreases at exhaustion, since exhaustion causes hyperventilation, which induces a reduction in PaCO 2. To test this hypothesis, ocular blood flow, blood pressure, and respiratory measurements were made in 12 healthy male subjects during cycle ergometer exercise at 75% of maximal heart rate, until exhaustion. Blood flows in the retinal and choroidal vasculature (RCV), the superior temporal retinal arteriole (STRA), and the superior nasal retinal arteriole (SNRA) were measured with the aid of laser-speckle flowgraphy every 3 min during the exercise. The conductance index (CI) in the ocular vasculature was calculated by dividing the blood flow by the mean arterial pressure (MAP). The mean arterial partial pressure of CO2 (PaCO2) was estimated from tidal volume and end-tidal CO2 partial pressure. MAP significantly increased from the resting baseline throughout the exercise, while PaCO2 was significantly decreased at exhaustion and during the recovery period. By 6 min after the onset of exercise, blood flow velocity in the RCV significantly increased by 32 ± 6% (mean ± SD) from the resting baseline value. At exhaustion, blood flow velocity in the RCV did not differ significantly from the resting baseline value, and the STRA blood flow was significantly decreased by 13 ± 4%. The CIs in the RCV, STRA, and SNRA were significantly decreased compared to baseline at exhaustion. These findings suggest that ocular blood flow is increased by submaximal exercise, whereas it is suppressed by the hypocapnia associated with exhaustion.

Original languageEnglish
Pages (from-to)3313-3318
Number of pages6
JournalEuropean Journal of Applied Physiology
Volume112
Issue number9
DOIs
Publication statusPublished - 2012 Sep
Externally publishedYes

Fingerprint

Exercise
Arterioles
Partial Pressure
Arterial Pressure
Blood Flow Velocity
Nose
Hypocapnia
Hyperventilation
Tidal Volume
Healthy Volunteers
Lasers
Heart Rate
Blood Pressure

Keywords

  • Choroidal circulation
  • Exhaustion
  • Hypocapnia
  • Retinal circulation

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Orthopedics and Sports Medicine
  • Physiology (medical)

Cite this

Ocular circulatory responses to exhaustive exercise in humans. / Ikemura, Tsukasa; Hayashi, Naoyuki.

In: European Journal of Applied Physiology, Vol. 112, No. 9, 09.2012, p. 3313-3318.

Research output: Contribution to journalArticle

Ikemura, Tsukasa ; Hayashi, Naoyuki. / Ocular circulatory responses to exhaustive exercise in humans. In: European Journal of Applied Physiology. 2012 ; Vol. 112, No. 9. pp. 3313-3318.
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