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Aging induced alterations in carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in humans
Author(s) -
Fisher James P,
Kim Areum,
Young Colin N,
Fadel Paul J
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.619.10
Subject(s) - baroreflex , medicine , blood pressure , cardiology , heart rate , reflex , rest (music) , baroreceptor
The arterial baroreflex is fundamental for evoking and maintaining appropriate cardiovascular adjustments to exercise. Given that exercise‐induced blood pressure (BP) responses appear exaggerated in older individuals, we sought to investigate how aging influences carotid baroreflex (CBR) regulation of BP during dynamic exercise. BP and heart rate (HR) were recorded at rest and during leg cycling performed at 50% HR reserve in 6 young (23±1 yr) and 6 older (60±1 yr) healthy men. Five second pulses of neck pressure and neck suction from +40 to −80 Torr were applied to determine the maximal gain (G MAX ) of the full CBR function curve and examine baroreflex resetting during exercise. G MAX was similar in both groups at rest and during exercise. However, in older subjects the operating point (OP) of the modeled function curve was located further away from the centering point (CP) and towards the reflex threshold, both at rest (OP minus CP; −12±3 vs. −3±4 mmHg, older vs. young, P<0.05) and during exercise (OP minus CP; −10±2 vs. 0±3 mmHg, older vs. young, P<0.05), compared with the younger group. In addition, the magnitude of CBR resetting was ≈40% greater in older individuals. These findings suggest that both at rest and during dynamic exercise, the ability of the CBR to defend against a hypotensive challenge is reduced with increased age, while the magnitude of exercise CBR resetting is augmented. Supported by NIH RO1HL093167