This paper is only available as a PDF. To read, Please Download here.
Abstract
Although the reduction in whole-body energy expenditure with aging has been well documented,
there is little information about the changes that individual organs undergo. We therefore
measured oxygen consumption in the heart, hepatomesenteric bed, and brain in elderly
subjects and young controls, using central venous catheter techniques and the application
of Fick's principle. We also measured whole-body, cardiac, and hepatomesenteric sympathetic
nervous activity using isotope dilution methodology. Cardiac, hepatomesenteric, and
cerebral oxygen consumption was similar in both groups. Whole-body and hepatomesenteric
sympathetic nervous activity was also similar in the study groups, whereas cardiac
norepinephrine (NE) spillover was significantly higher in the elderly. In contrast
to the young, cardiac sympathetic nervous activity as assessed from NE spillover was
not related to either cardiac oxygen consumption or cardiac work in the elderly. The
data suggest that although oxygen consumption in the heart, hepatomesenteric bed,
and brain are not different between young and elderly individuals, the relationship
between sympathetic nervous activity and oxygen consumption in individual organs may
alter with aging.
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Metabolism - Clinical and ExperimentalAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Regulation of energy expenditure in aging humans.Annu Rev Nutr. 1990; 10: 255-275
- Influence of aerobic capacity, body composition, and thyroid hormones on the age-related decline in resting metabolic rate.Metabolism. 1992; 41: 915-921
- Effect of age on body composition and resting metabolic rate.Am J Physiol. 1990; 259: E233-E238
- Aging and energy expenditure.Am J Clin Nutr. 1991; 53: 821-825
- Energy expenditure, physical activity and basal metabolic rate of elderly subjects.Br J Nutr. 1995; 73: 571-581
- Influence of age and endurance training on metabolic rate and hormones in healthy men.Am J Physiol. 1990; 259: E66-E72
- Effect of muscle mass decrease on age-related BMR changes.J Appl Physiol. 1977; 43: 1001-1006
- Muscle and whole body metabolism after norepinephrine.Am J Physiol. 1994; 266: E877-E884
- Energy and protein requirements.in: Report of a joint FAO/WHO/UNU expert consultation. ed 4. WHO Tech Rep Ser. 724. 1985: 43
- Skeletal muscle metabolism is a major determinant of resting energy expenditure.J Clin Invest. 1990; 86: 1423-1427
- Organ physiology of aging.Surg Clin North Am. 1994; 74: 23-39
- Reduced sympathetic nervous activity.in: A potential mechanism predisposing to body weight gain. ed 4. J Clin Invest. 92. 1993: 1730-1735
- Age-dependence of norepinephrine kinetics in normal subjects.Clin Sci. 1981; 60: 217-219
- Age differences in plasma norepinephrine kinetics in humans.J Gerontol. 1986; 41: 319-324
- Effects of age and level of physical activity on plasma norepinephrine kinetics.Am J Physiol. 1990; 258: E256-E262
- Aging effects on human sympathetic neuronal function.Am J Physiol. 1995; 268: R278-R285
- Overflow of catecholamine neurotransmitters to the circulation: Source, fate, and functions.Physiol Rev. 1990; 70: 963-985
- Determination of norepinephrine apparent release rate and clearance in humans.Life Sci. 1979; 25: 1461-1470
- Regional sympathetic nervous activation after a large meal in humans.Clin Sci. 1995; 89: 145-154
- Fallibility of plasma norepinephrine measurements in studying postprandial sympathetic nervous responses.J Auton Nerv Syst. 1995; 56: 97-104
- Plasma norepinephrine kinetics in humans.J Auton Nerv Syst. 1984; 11: 125-144
- Assessment of human sympathetic nervous system activity from measurements of norepinephrine turnover.Hypertension. 1988; 11: 3-20
- Increased sympathetic nervous activity and the effects of its inhibition with clonidine in alcoholic cirrhosis.Ann Intern Med. 1992; 116: 446-455
- Postprandial sympathoadrenal activity: Its relation to metabolic and cardiovascular events and to changes in meal frequency.Clin Sci. 1995; 89: 349-357
- Echocardiographic assessment of left ventricular hypertrophy: Comparison to necropsy findings.Am J Cardiol. 1986; 57: 450-458
- Interpretation and Uses of Medical Statistics.in: ed 4. Blackwell Scientific, London, UK1991: 355
- Coronary hemodynamics and myocardial metabolism during and after pacing stress in normal humans.Am J Physiol. 1989; 257: E309-E317
- Physiology of cardiovascular aging.Physiol Rev. 1993; 73: 725-764
- Cardiomyopathy of the aging human heart: Myocyte loss and reactive cellular hypertrophy.Circ Res. 1991; 68: 1560-1568
- Pathology of the senescent heart: Anatomic observations on 237 autopsy studies of patients 90 to 105 years old.Mayo Clin Proc. 1988; 63: 552-564
- Excitation-contraction in rat myocardium: Alterations with adult aging.Am J Physiol. 1984; 246: H784-H791
- Chronic exercise training protects aged cardiac muscle against hypoxia.J Clin Invest. 1989; 83: 778-784
- Kinetics of hepatic amino-nitrogen conversion in ageing man.Liver. 1994; 14: 288-294
- Galactose elimination capacity and liver volume in aging man.Hepatology. 1988; 8: 1079-1083
- Quantitative liver function in the elderly assessed by galactose elimination capacity, aminopyrine demethylation and caffeine clearance.J Hepatol. 1986; 3: 174-181
- Aging and the brain.Curr Opin Neurol. 1994; 7: 287-293
- Aging, energy, and oxidative stress in neurodegenerative diseases.Ann Neurol. 1995; 38: 357-366
- Arterial oxygen tension in relation to age in healthy subjects.Respiration. 1968; 25: 3-13
- Age and the cardiovascular system.N Engl J Med. 1992; 327: 1735-1739
- Effects of aging on the responsiveness of the human cardiac sympathetic nerves to stressors.Circulation. 1995; 91: 351-358
- Sympathetic nervous system activity, body fatness, and body fat distribution in younger and older males.J Appl Physiol. 1995; 78: 802-806
- Effects of aging on catecholamine metabolism.J Clin Endocrinol Metab. 1985; 60: 479-484
- Age-related changes in β-adrenergic neuroeffector systems in the human heart.Circulation. 1994; 90: 1225-1238
- Contractile and biochemical correlates of β-adrenergic stimulation of the aged human heart.Am J Physiol. 1980; 239: H501-H508
- The nitrous oxide method for quantitative determination of cerebral blood flow in man: Theory, procedure and normal values.J Clin Invest. 1948; 27: 476-483
- Arterial pCO2 and cerebral hemodynamics.Am J Physiol. 1964; 206: 25-35
- Cerebral blood flow changes in benign aging and cerebrovascular disease.Neurology. 1984; 34: 855-862
- Regional cerebral blood flow and oxygen consumption in human aging.Stroke. 1984; 15: 635-641
- Metabolism of [3H]norepinephrine in rat brain.J Neurochem. 1965; 12: 25-30
- Hepatomesenteric release and removal of norepinephrine in swine.Am J Physiol. 1995; 268: R924-R930
Article info
Publication history
Accepted:
July 22,
1996
Received:
November 29,
1995
Footnotes
☆Supported by an institute grant from the National Health and Medical Research Council, Australia, to the Baker Medical Research Institute.
Identification
Copyright
© 1996 Published by Elsevier Inc.
