What question did this study set out to answer?

To determine if reduced cardiac output during exercise leads to vasoconstriction in skeletal muscles.

November 1, 1992Journal of Applied Physiology

Leg vasoconstriction during dynamic exercise with reduced cardiac output

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Why the study?

Does cardioselective beta-1 blockade reduce leg blood flow and vascular conductance during dynamic exercise?

Population

9 subjects performing four 8-min bouts of cycling exercise at 71 +/- 12 to 145 +/- 13 W

Comparison

Cardioselective adrenergic blockade vs Control condition (exercise without beta-blockade)

Design

Other

Authors

JPJames A. PawelczykPennsylvania State University BHBirgitte HanelCopenhagen University Hospital JPJames A. PawelczykPennsylvania State University

Discussion

Member takes

Implication

May reduce exercising muscle perfusion in patients on beta-1 blockers; hypothesis-generating and should not yet change practice.

Key Points

To determine if reduced cardiac output during exercise leads to vasoconstriction in skeletal muscles.
Nine subjects performed cycling exercise with varying workloads for four 8-minute bouts.
Leg blood flow and cardiac output were measured using indocyanine green injections and monitored for arterial/venous pressures.
Cardioselective beta 1 adrenergic blockade was administered to observe effects on vascular conductance and norepinephrine spillover.
During beta 1-blockade, leg blood flow decreased from 5.4 l/min to 4.8 l/min (P < 0.01).
Vascular conductance reduced from 5.2 cl.min-1.mmHg-1 to 4.6 cl.min-1.mmHg-1 (P < 0.05).
Norepinephrine spillover increased from 2.64 nM/min to 5.62 nM/min (P < 0.05) during beta 1-blockade.

Structured PICO

Does cardioselective beta-1 blockade reduce leg blood flow and vascular conductance during dynamic exercise?

Population

9 subjects performing four 8-min bouts of cycling exercise at 71 +/- 12 to 145 +/- 13 W (40-84% maximal oxygen uptake)

Intervention

Cardioselective (beta 1) adrenergic blockade (0.2 mg/kg metoprolol iv)

Comparator

Control condition (exercise without beta-blockade)

Outcome

Leg blood flow and cardiac outputsurrogate

A reduction in cardiac output during dynamic exercise via beta-1 blockade results in vasoconstriction of active skeletal muscle vasculature, evidenced by reduced leg blood flow and increased norepinephrine spillover.

Cite This Study

Pawelczyk et al. (1992) studied this question.

synapsesocial.com/papers/6a23e9c698edd3e1959eea2c https://doi.org/10.1152/jappl.1992.73.5.1838

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Leg vasoconstriction during dynamic exercise with reduced cardiac output

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Leg vasoconstriction during dynamic exercise with reduced cardiac output

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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Also Consider