What is the clinical evidence from this study?

Study design: Other. Intervention: Graded lower body negative pressure (LBNP) vs. Baseline phase in -6° head-down tilt posture. Primary outcome: Central, peripheral, and cerebral hemodynamic responses.

What does this research mean for the field?

Graded lower body negative pressure during head-down tilt induces comparable cerebral blood flow responses between sexes and regions, with sex differences primarily manifesting in systemic and peripheral hemodynamics. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To investigate acute central, peripheral, and regional cerebral hemodynamic responses to graded lower body negative pressure during -6° head-down tilt, focusing on sex-related differences.

July 1, 2026European Journal of Applied PhysiologyOpen Access

Sex-based differences in central and cerebral hemodynamic responses to lower body negative pressure (LBNP): an experimental study

Q: What are the key findings of this study?

Graded lower body negative pressure (from -20 to -40 mmHg) induced comparable cerebral responses between sexes, while sex differences occurred primarily in systemic and peripheral hemodynamics.

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Key result

LBNP induces comparable cerebral responses across sexes despite differing systemic and peripheral hemodynamics.

n=30

Why the study?

The effectiveness of lower body negative pressure (LBNP) as an in-flight countermeasure against cardiovascular deconditioning is debated, with gaps in understanding cerebral hemodynamics and sex-related differences.

Does graded lower body negative pressure affect central, peripheral, and cerebral hemodynamics differently between sexes in subjects exposed to head-down tilt posture?

Population

30 subjects (15 females, 15 males)

Comparison

Graded LBNP (-20 to -40 mmHg) vs baseline during -6° head-down tilt posture

Design

Experimental study

Authors

FTFrancesco TripoliPolytechnic University of Turin LRL. RidolfiPolytechnic University of Turin MRM. RomanelliUniversity of Turin

Discussion

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Implication

Sex differences in LBNP responses merit consideration in future protocols; hypothesis-generating and leaves open clinical translation.

Key Points

To investigate acute central, peripheral, and regional cerebral hemodynamic responses to graded lower body negative pressure during -6° head-down tilt, focusing on sex-related differences.
Assessed 30 young adults (15 females, 15 males) during a 15-min baseline at -6° head-down tilt followed by three 5-min stages of graded lower body negative pressure (-20 to -40 mmHg).
Continuously recorded arterial blood pressure, heart rate, cardiac output, and total peripheral resistance via finger photo-plethysmography alongside forearm and forehead near-infrared spectroscopy.
Measured anterior and posterior regional cerebral blood flow velocities using transcranial Doppler ultrasound in the middle and posterior cerebral arteries.
Arterial blood pressure changed significantly across lower body negative pressure stages in females (p < 0.001) but not in males (p = 0.218), with significant sex differences also observed in total peripheral resistance and forearm tissue oxygenation.
Cerebral blood velocities in both middle and posterior cerebral arteries showed comparable decreasing trends at higher negative pressure levels without significant changes in spatially resolved spectroscopy parameters.
Sex had a significant effect on cerebral circulation only in the cerebrovascular conductance of the posterior cerebral artery.

Structured PICO

Does graded lower body negative pressure affect central, peripheral, and cerebral hemodynamics differently between sexes in subjects exposed to head-down tilt posture?

Population

30 subjects (15 females, 15 males) undergoing graded lower body negative pressure during -6° head-down tilt posture to assess hemodynamic responses.

Intervention

Graded lower body negative pressure (LBNP) (from -20 to -40 mmHg) during exposure to -6° head-down tilt posture (HDT)

Comparator

15-min baseline phase in -6° HDT

Outcome

Acute central, peripheral, and cerebral hemodynamic responses (heart rate, blood pressure, cardiac output, total peripheral resistance, cerebral blood velocities, NIRS parameters)surrogate

Graded lower body negative pressure induces comparable anterior and posterior cerebral hemodynamic responses, while sex differences occur primarily in systemic and peripheral cardiovascular responses.

Cite This Study

Tripoli et al. (2026) studied this question. Graded lower body negative pressure (LBNP) vs. Baseline phase in -6° head-down tilt posture was evaluated on Central, peripheral, and cerebral hemodynamic responses. Graded lower body negative pressure (from -20 to -40 mmHg) induced comparable cerebral responses between sexes, while sex differences occurred primarily in systemic and peripheral hemodynamics.

synapsesocial.com/papers/6a44af055cd2549c8bc4415e https://doi.org/10.1007/s00421-026-06313-7

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Sex-based differences in central and cerebral hemodynamic responses to lower body negative pressure (LBNP): an experimental study

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Sex-based differences in central and cerebral hemodynamic responses to lower body negative pressure (LBNP): an experimental study

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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