Faculty Collaboration Database

Muscle sympathetic nerve activity during postural change in healthy young and older adults. Clin Auton Res 1995 Feb;5(1):57-60

Date

02/01/1995

Pubmed ID

7780292

DOI

10.1007/BF01845500

Scopus ID

2-s2.0-0028959671 (requires institutional sign-in at Scopus site)   26 Citations

Abstract

Recent evidence suggests that during orthostatic stress the reflex increase in muscle sympathetic nerve activity may be diminished in older adults. To test this hypothesis, we measured muscle sympathetic nerve activity, plasma noradrenaline concentrations, heart rate, and arterial blood pressure in twelve young (mean, 25 years; range, 19-29 years) adults and 14 older (mean 64 years; range, 60-74 years) healthy adults, while supine and during upright sitting. Supine control levels of muscle sympathetic nerve activity were higher in the older subjects (35 +/- 1 vs. 25 +/- 1 bursts/min, p < 0.05), but there were no differences in plasma noradrenaline concentrations, heart rate or arterial pressure. Despite higher supine control levels in the older group, the absolute unit increases in muscle sympathetic nerve activity in response to upright sitting (p < 0.05 vs. control) were not different in the two groups (7 +/- 1 vs. 7 +/- 1 bursts/min), nor were the increases in plasma noradrenaline concentrations. Heart rate did not increase above supine control in response to sitting in either group. Arterial pressure increased slightly (p < 0.05, supine vs. control), but there were no age-related differences. These results indicate that, contrary to recent findings, the reflex increases in muscle sympathetic nerve activity and plasma noradrenaline concentrations and regulation of arterial pressure during this natural orthostatic stress are well preserved in older healthy men and women.

Author List

Ng AV, Johnson DG, Callister R, Seals DR

Author

Alexander V. Ng PhD Associate Professor in the Exercise Science department at Marquette University

MESH terms used to index this publication - Major topics in bold

Adult
Age Factors
Aged
Female
Humans
Male
Middle Aged
Neuromuscular Junction
Posture
Stress, Physiological
Sympathetic Nervous System