Relationship between cerebral arterial inflow and venous outflow during dynamic supine exercise

Q: What are the key findings of this study?

Dynamic supine exercise modified cerebral venous outflow, with changes in internal carotid and vertebral artery blood flow correlating with internal jugular (r=0.73, P=0.001) and vertebral vein flow.

Q: What is the clinical evidence from this study?

Population: Healthy normotensive individuals undergoing dynamic supine exercise (n=9). Intervention: Dynamic supine cycling exercise vs. Supine rest (baseline). Primary outcome: Correlation between relative change in internal carotid artery (ICA) blood flow and internal jugular vein (IJV) blood flow from baseline to exercise (r = 0.73, p=0.001).

Q: What does this research mean for the field?

Dynamic supine exercise alters cerebral venous outflow, demonstrating coupled regulation between arterial inflow and venous outflow in both anterior and posterior cerebral circulation. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Kohei Sato; Naoko Oba; Takuro Washio; Hiroyuki Sasaki; Anna Oue; Aki Otsuki; Tomoko Sadamoto; Shigehiko Ogoh

doi:10.14814/phy2.13292

June 1, 2017Physiological ReportsOpen Access

Relationship between cerebral arterial inflow and venous outflow during dynamic supine exercise

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Key result

Dynamic supine exercise alters cerebral venous outflow, closely tracking arterial inflow changes.

r = 0.73
P=0.001
n=9

Figures

Why the study?

Does dynamic supine cycling exercise modify cerebral venous outflow in relation to cerebral arterial inflow in healthy young adults?

Key Points

To identify the relationship between cerebral arterial inflow and venous outflow during dynamic exercise in the supine position.
Nine subjects performed dynamic cycling exercise in a supine position at light (EX1) and moderate (EX2) workloads.
Ultrasonography was used to measure blood flow in the internal carotid artery (ICA), vertebral artery (VA), internal jugular vein (IJV), and vertebral vein (VV).
During light exercise, ICA blood flow increased 25 ± 17% (P < 0.05) and IJV blood flow increased 19 ± 15% (P = 0.035); during moderate exercise, ICA blood flow returned near baseline (10 ± 27%, P = 1.00) while IJV blood flow decreased below baseline (-21 ± 26%, P = 0.008).
VA blood flow increased during light exercise (16 ± 12%, P < 0.05) and was maintained during moderate exercise (22 ± 18%, P = 0.02), whereas VV blood flow progressively increased with workload (71 ± 47%, P < 0.05).
Exercise-induced changes from baseline were significantly correlated between ICA and IJV blood flow (r = 0.73, P = 0.001) as well as between VA and VV blood flow (r = 0.52, P = 0.028).

Structured PICO

Does dynamic supine cycling exercise modify cerebral venous outflow in relation to cerebral arterial inflow in healthy young adults?

P

Population

9 healthy normotensive young adults (mean age 21.7 years, 44.4% female) free of cardiovascular, pulmonary, or kidney disease undergoing acute submaximal supine cycling exercise.

I

Intervention

Dynamic supine cycling exercise at light workload (EX1: starting at 20 W and adjusted to target heart rate 100–110 beats/min, ~40% VO2peak) and moderate workload (EX2: target heart rate 150–160 beats/min, ~70% VO2peak), each stage lasting ~10 minutes.

C

Comparator

Baseline supine rest (30 minutes quiet rest prior to exercise).

O

Outcome

Blood flow (BF) changes and correlations between cerebral arterial inflow (internal carotid artery [ICA] and vertebral artery [VA]) and venous outflow (internal jugular vein [IJV] and vertebral vein [VV]) measured via Doppler and B-mode ultrasonography during light and moderate supine exercise.surrogate

Main Result

Effect estimate: r = 0.73

p-value: p=0.001

Demonstrates physiological coupling between regional cerebral arterial inflow and venous outflow in both the anterior (ICA-IJV) and posterior (VA-VV) cerebral circulations during dynamic supine exercise.

Limitations

Inability to simultaneously measure blood flow in the cerebral arteries and veins during exercise, introducing a time lag
Potential for artifactual compression of the low-pressure internal jugular vein by the ultrasound probe
Unilateral (right-sided) blood flow measurements meant that the sum of arterial inflows did not quantitatively match the sum of venous outflows
Unable to simultaneously measure blood flow in the cerebral arteries and veins during exercise (time lag in measurements)
Potential risk of internal jugular vein compression artifact from the ultrasound probe
Sum of ICA and VA blood flow did not quantitatively match the sum of IJV and VV blood flow because only the right side was measured

Implication

Supports cerebral arterial-venous flow coupling during supine exercise in healthy adults; leaves open relevance to upright posture or clinical populations.

Abstract

The regulation of cerebral venous outflow during exercise has not been studied systematically. To identify relations between cerebral arterial inflow and venous outflow, we assessed the blood flow (BF) of the cerebral arteries (internal carotid artery: ICA and vertebral artery: VA) and veins (internal jugular vein: IJV and vertebral vein: VV) during dynamic exercise using ultrasonography. Nine subjects performed a cycling exercise in supine position at a light and moderate workload. Similar to the ICA BF, the IJV BF increased from baseline during light exercise (P < 0.05). However, the IJV BF decreased below baseline levels during moderate exercise, whereas the ICA BF returned near resting levels. In contrast, BF of the VA and VV increased with the workload (P < 0.05). The change in the ICA or VA BF from baseline to exercise was significantly correlated with the change in the IJV (r = 0.73, P = 0.001) or VV BF (r = 0.52, P = 0.028), respectively. These findings suggest that dynamic supine exercise modifies the cerebral venous outflow, and there is coupling between regulations of arterial inflow and venous outflow in both anterior and posterior cerebral circulation. However, it remains unclear whether changes in cerebral venous outflow influence on the regulation of cerebral arterial inflow during exercise.

Discussion

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Cite This Study

Sato et al. (2017) studied Healthy normotensive individuals undergoing dynamic supine exercise (n=9). Dynamic supine cycling exercise vs. Supine rest (baseline) was evaluated on Correlation between relative change in internal carotid artery (ICA) blood flow and internal jugular vein (IJV) blood flow from baseline to exercise (r = 0.73, p=0.001). Dynamic supine exercise modified cerebral venous outflow, with changes in internal carotid and vertebral artery blood flow correlating with internal jugular (r=0.73, P=0.001) and vertebral vein flow.

synapsesocial.com/papers/6a7c4ef6f056b38aaddf9998 https://doi.org/10.14814/phy2.13292

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Relationship between cerebral arterial inflow and venous outflow during dynamic supine exercise

Figures

Key Points

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Relationship between cerebral arterial inflow and venous outflow during dynamic supine exercise

Figures

Key Points

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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