What question did this study set out to answer?

To determine how an 8-month endurance exercise training program alters cardiovascular reflex control and tolerance to lower body negative pressure.

November 1, 1992Medicine & Science in Sports & Exercise

Reduction in LBNP tolerance following prolonged endurance exercise training

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Why the study?

Does an 8-month endurance exercise training program alter tolerance to lower body negative pressure in young men?

Population

8 young men

Comparison

8-month endurance exercise training program vs Pre-training baseline

Design

Cohort

Follow-up

8 months

Authors

GSGlen StevensCleveland Clinic BFB. H. ForesmanUniversity of North Texas XSXiangrong ShiUniversity of North Texas

Discussion

Member takes

Implication

Endurance training may reduce orthostatic tolerance in young men; leaves open mechanisms and relevance to broader populations.

Key Points

To determine how an 8-month endurance exercise training program alters cardiovascular reflex control and tolerance to lower body negative pressure.
Assessed 8 young men before and after an 8-month endurance exercise training regimen (N=8).
Measured VO2max, total blood volume, plasma volume, and hemodynamic responses (cardiac output, heart rate, blood pressure, forearm blood flow, and leg volume) across 0 to -45 torr lower body negative pressure (LBNP).
Evaluated LBNP tolerance to presyncope via the cumulative stress index (CSI) and modeled predictors using stepwise linear regression.
Training significantly elevated VO2max (mean = +27.4%, P < 0.001), total blood volume (mean = +15.8%, P < 0.02), and plasma volume (mean = +16.5%, P < 0.02).
Tolerance to LBNP significantly declined in all subjects after training (mean CSI change = -24%, P < 0.001).
Stepwise linear regression revealed that reduced peripheral vascular resistance response (model R2 = 0.853), change in total blood volume (model R2 = 0.981), and greater systolic blood pressure drops (model R2 = 1.0) predicted the training-induced decline in tolerance.

Structured PICO

Does an 8-month endurance exercise training program alter tolerance to lower body negative pressure in young men?

Population

8 young men

Intervention

8-month endurance exercise training program

Comparator

Pre-training baseline

Outcome

Tolerance to lower body negative pressure (LBNP) assessed by the cumulative stress index (CSI) to presyncopesurrogate

Prolonged endurance exercise training reduces tolerance to lower body negative pressure, suggesting altered reflex control of vasomotion and cardiac output.

Cite This Study

Stevens et al. (1992) studied this question.

synapsesocial.com/papers/6a7be20ecbabed012ec62c27 https://doi.org/10.1249/00005768-199211000-00007

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Reduction in LBNP tolerance following prolonged endurance exercise training

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Reduction in LBNP tolerance following prolonged endurance exercise training

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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Also Consider