August 1, 1998Hypertension
Augmented Cardiopulmonary and Integrative Sympathetic Baroreflexes but Attenuated Peripheral Vasoconstriction With Age
Key result
Older men exhibited approximately 150% greater sympathetic nerve activity responses to hypovolemia (P<0.01) but 50% smaller forearm vascular resistance responses (P<0.05) compared to young men.
Why the study?
Does aging affect cardiopulmonary and integrative sympathetic baroreflex control during hypovolemia in healthy men?
Population
23 healthy adult men, comprising young and older subjects.
Comparison
Progressive hypovolemia produced by graded lower… vs Young versus older subjects.
Design
Cross-sectional
Authors
Discussion
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Implication
Highlights potential age-related sympathetic-vascular uncoupling during hypovolemia; leaves open implications for orthostatic tolerance in older adults.
Study Design
Type
Cross-Sectional (n=23)
Structured PICO
Does aging affect cardiopulmonary and integrative sympathetic baroreflex control during hypovolemia in healthy men?
P
Population
23 healthy adult men (11 young, 12 older) evaluated for sympathetic nerve activity and vascular resistance during progressive hypovolemia.
E
Exposure
Progressive hypovolemia produced by graded (-5 to -40 mm Hg) lower body negative pressure (LBNP).
C
Comparator
Young versus older subjects.
O
Outcome
Skeletal muscle sympathetic nerve activity (MSNA) and forearm vascular resistance (FVR) responses to hypovolemia.surrogate
Main Result
Effect estimate: ~150% greater
p-value: p=<0.01
Aging augments central sympathetic outflow during hypovolemia, but reflex-mediated increases in limb vascular resistance are smaller due to attenuated vasoconstrictor responsiveness.
Cite This Study
Davy et al. (1998) conducted a cross-sectional in Healthy (n=23). Older age vs. Young age was evaluated on DeltaMSNA/deltaPVP (sympathetic nerve activity response to hypovolemia) (~150% greater, p=<0.01). Older men exhibited approximately 150% greater sympathetic nerve activity responses to hypovolemia (P<0.01) but 50% smaller forearm vascular resistance responses (P<0.05) compared to young men.