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.
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References
Rowell LB.Human Cardiovascular Control. New York: Oxford University Press, 1993.
Caird FI, Andrews GR, Kennedy RD. Effect of posture on blood pressure in the elderly.Br Heart J 1973;35: 527–530.
Johnson RH, Smith AC, Spalding MK, Wollner L. Effect of posture on blood pressure in elderly patients.Lancet 1965;i: 731–733.
Wollner L. Postural hypotension in the elderly.Age Ageing 1978; (suppl 7): 112–118.
Lipsitz LA. Orthostatic hypotension in the elderly.New Engl J Med 1989;321: 952–957.
Mader SL, Josephson KR, Rubenstein LZ. Low prevalence of postural hypotension among community-dwelling elderly.JAMA 1987;258: 1511–1514.
Taylor JA, Hand GA, Johnson DG, Seals DR. Sympatho-circulatory regulation of arterial pressure during orthostatic stress in young and older men.Am J Physiol 1992;263: R1147-R1155.
Ebert TJ, Hughes CV, Tristani FE, Barney JA, Smith JJ. Effect of age and coronary heart disease on the circulatory responses to graded lower body negative pressure.Cardiovasc Res 1982;16: 663–669.
Palmer GJ, Ziegler MG, Lake CR. Response of norepinephrine and blood pressure to stress increases with age.J Gerontol 1978;33: 482–487.
Sachs C, Hamberger B, Kaijser L. Cardiovascular responses and plasma catecholamines in old age.Clin Physiol 1985;5: 553–565.
Sowers JR, Rubenstein LZ, Stern N. Plasma norepinephrine responses to posture and isometric exercise increase with age in the absence of obesity.J Gerontol 1983;38: 315–317.
Young JB, Rowe JW, Pallotta JA, Sparrow D, Landsberg L. Enhanced plasma norepinephrine response to upright posture and oral glucose administration in elderly human subjects.Metabolism 1980;29: 532–539.
Dambrink JHA, Wieling W. Circulatory response to postural change in healthy male subjects.Clin Sci 1987;72: 335–341.
Iwase S, Mano T, Watanabe T, Saito M, Kobayashi F. Age-related changes of sympathetic outflow to muscles in humans.J Gerontol 1991;46: M1-M5.
Ng AV, Callister R, Johnson DG, Seals DR. Age and gender influence muscle sympathetic nerve activity at rest in healthy humans.Hypertension 1993;21: 498–503.
Ng AV, Callister R, Johnson DG, Seals DR. Sympathetic neural reactivity to stress does not increase with age in healthy humans.Am J Physiol (Heart Circ Physiol) 1994;267: H344-H353.
Sallis JF, Haskell WL, Wood PD, Fortmann SP, Rogers T, Blair SN, Paffenbarger RS. Physical activity assessment methodology in the five-city project.Am J Epidemiol 1985;121: 91–106.
Seals DR, Chase PB, Taylor JA. Autonomic mediation of the pressor responses to isometric exercise in humans.J Appl Physiol 1988;64: 2190–2196.
Wallin BG, Fagius J. Peripheral sympathetic neural activity in conscious humans.Annu Rev Physiol 1988;50: 565–576.
Peuler JD, Johnson GA. Simultaneous single isotope radioenzymatic assay of plasma norepinephrine, epinephrine, and dopamine.Life Sci 1977;21: 625–636.
Seals DR. Sympathetic neural adjustments to stress in physically trained and untrained humans.Hypertension 1991;17: 36–43.
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Ng, A.V., Johnson, D.G., Callister, R. et al. Muscle sympathetic nerve activity during postural change in healthy young and older adults. Clinical Autonomic Research 5, 57–60 (1995). https://doi.org/10.1007/BF01845500
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DOI: https://doi.org/10.1007/BF01845500