Down training of the elderly soleus H reflex with the use of a spinally induced balance perturbation

2002 ◽  
Vol 93 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Richard G. Mynark ◽  
David M. Koceja
Keyword(s):  
Postural Stability ◽  
Balance Training ◽  
The Elderly ◽  
Static Stability ◽  
H Reflex ◽  
Spinal Reflex ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Young Subjects ◽  
Healthy Elderly Subjects

The purpose of this study was to determine the ability of the elderly central nervous system to modulate spinal reflex output to functionally decrease a spinally induced balance perturbation. In this case, the soleus H reflex was used as the source of perturbation. Therefore, decreasing (down training) of the soleus H reflex was necessary to counteract this perturbation and to better maintain postural control. In addition to assessing the effect of this perturbation on the H reflex, static postural stability was measured to evaluate possible functional effects. Ten healthy young subjects (age: 27.0 ± 4.6 yr) and 10 healthy elderly subjects (age: 71.4 ± 5.1 yr) participated in this study. Subjects underwent balance perturbation on 2 consecutive days. On day 1 of perturbation, significant down training of the soleus H reflex was demonstrated in both young (−20.4%) and elderly (−18.7%) subjects. On day 2 of perturbation, significant down training of the soleus H reflex was again demonstrated in both young (−24.6%) and elderly (−21.0%) subjects. Analysis of static stability after the 2 days of balance perturbation revealed a significant 10.1% decrease in the area of sway in elderly subjects. In conclusion, this study demonstrated that healthy, elderly subjects compared with young subjects were equally capable of down training the soleus H reflex in response to a balance perturbation. Furthermore, the improvement in static stability through balance training may provide further evidence that balance can be retrained and rehabilitated in subjects with decreased reflex function.

Atrial natriuretic factor in the elderly: diminished response to epinephrine

1989 ◽  
Vol 257 (6) ◽  
pp. E866-E870 ◽  
Author(s):  
L. A. Morrow ◽  
G. S. Morganroth ◽  
T. J. Hill ◽  
J. A. Sanfield ◽  
S. G. Rosen ◽  
...  
Keyword(s):  
Atrial Natriuretic Factor ◽  
Human Subjects ◽  
The Elderly ◽  
Elderly Subjects ◽  
Adrenergic Stimulation ◽  
Healthy Elderly ◽  
Natriuretic Factor ◽  
Young Subjects ◽  
Healthy Elderly Subjects ◽  
Atrial Natriuretic

We have previously found that epinephrine (EPI) increases plasma immunoreactive atrial natriuretic factor (irANF) in young human subjects. Because elderly humans have decreased sensitivity to adrenergic stimulation, we compared plasma irANF responses to intravenous infusion of EPI, 5 micrograms/min for 80 min in six young (ages 20-29) and nine old (ages 62-75) healthy subjects. In addition, we measured plasma irANF responses of the nine old subjects to 1 liter of normal saline infused over 30 min. Young and old subjects had similar basal EPI levels [108 +/- 18 vs. 106 +/- 10 (SE) pg/ml], but basal irANF levels tended to be higher in the old (32 +/- 7 vs. 50 +/- 8 pmol/l, P = 0.15). The young subjects had a significant increase in irANF levels after the EPI infusion (32 +/- 7 vs. 59 +/- 11 pmol/l, P less than 0.02), but there was no change in irANF in the old (50 +/- 8 vs. 48 +/- 7 pmol/l) despite similar plasma EPI levels in young and old (1,125 +/- 57 vs. 1,183 +/- 52 pg/ml). In contrast, the irANF response of the old subjects to saline infusion was striking: all nine subjects demonstrated a rise in irANF (P less than 0.01); mean levels increased from 54 +/- 4 pmol/l to a peak of 122 +/- 23 pmol/l. We conclude that healthy elderly subjects have a defect in EPI-stimulated ANF secretion, a finding compatible with other evidence for diminished sensitivity to adrenergic stimulation in aging.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of dynamic visual environments on postural sway in the elderly

1999 ◽  
Vol 9 (3) ◽  
pp. 197-205
Author(s):  
L.L. Borger ◽  
S.L. Whitney ◽  
M.S. Redfern ◽  
J.M. Furman
Keyword(s):  
Visual Information ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Age Groups ◽  
The Elderly ◽  
Visual Scene ◽  
Elderly Subjects ◽  
Mean Velocity ◽  
Healthy Elderly ◽  
Young Subjects

Postural sway during stance has been found to be sensitive to moving visual scenes in young adults, children, and those with vestibular disease. The effect of visual environments on balance in elderly individuals is relatively unknown. The purpose of this study was to compare postural sway responses of healthy elderly to those of young subjects when both groups were exposed to a moving visual scene. Peak to peak, root mean squared, and mean velocity of the center of pressure were analyzed under conditions combining four moving scene amplitudes ( 2 . 5 ∘ , 5 ∘ , 7 . 5 ∘ , 10 ∘ ) and two frequencies of scene movement (0.1 Hz, 0.25 Hz). Each visual condition was tested with a fixed floor and sway referenced platform. Results showed that elderly subjects swayed more than younger subjects when experiencing a moving visual scene under all conditions. The elderly were affected more than the young by sway referencing the platform. The differences between the two age groups were greater at increased amplitudes of scene movement. These results suggest that elderly are more influenced by dynamic visual information for balance than the young, particularly when cues from the ankles are altered.

Effect of ‘Autonomic Blockade’ on Cardiac β-Adrenergic Chronotropic Responsiveness in Healthy Young, Healthy Elderly and Endurance-Trained Elderly Subjects

1994 ◽  
Vol 87 (3) ◽  
pp. 297-302 ◽  
Author(s):  
G. A. Ford ◽  
O. F. W. James
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Geometric Mean ◽  
Cardiovascular Responses ◽  
The Elderly ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Autonomic Blockade ◽  
Young Subjects

1. Cardiac chronotropic responses to isoprenaline are reduced with ageing in man. It is unclear whether this is due to reduced cardiac β-adrenergic sensitivity or to age-associated differences in reflex cardiovascular responses to the vasodilatory effects of isoprenaline. Age-associated changes in physical activity are also reported to influence β-adrenergic sensitivity. 2. The aim of the present study was to determine the contribution of alterations in reflex changes in parasympathetic and sympathetic influences and physical fitness to the age-associated reduction in cardiac chronotropic responses to β-adrenergic agonists. 3. The effect of ‘autonomic blockade’ with atropine (40 μg/kg intravenously) and clonidine (4 μg/kg intravenously) on blood pressure, heart rate and chronotropic responses to intravenous bolus isoprenaline doses was determined in eight healthy young (mean age 21 years), nine healthy elderly (72 years) and 10 endurance-trained elderly (69 years) subjects. 4. Elderly subjects had a reduced increase in heart rate after atropine (young, 49 ± 9 beats/min; elderly, 36 ± 5 beats/min; endurance-trained elderly, 34 ± 12 beats/min; P < 0.01) and did not demonstrate the transient increase in systolic blood pressure after clonidine observed in young subjects (young, 11 ± 10 mmHg; elderly, −12 ± 16 mmHg; endurance-trained elderly, −18 ± 11 mmHg; P < 0.01). 5. Cardiac chronotropic sensitivity to isoprenaline after ‘autonomic blockade’ increased in the young but decreased in the elderly subjects. The isoprenaline dose that increased heart rate by 25 beats/min before and after autonomic blockade' was: young, before 1.6 μg, after 2.8 μg, P < 0.01 (geometric mean, paired test); elderly, before 6.9 μg, after 3.6 μg, P < 0.05; endurance-trained elderly, before 5.9 μg, after 4.0 μg, P < 0.05. Cardiac chronotropic sensitivity to isoprenaline was significantly reduced in elderly compared with young subjects before (P < 0.01) but was similar after (P = 0.09) ‘autonomic blockade’. Chronotropic sensitivity did not differ between healthy and endurance-trained elderly subjects before or after ‘autonomic blockade’. 6. The age-associated reduction in cardiac chronotropic responses to bolus isoprenaline is primarily due to an age-related reduction in the influence of reflex cardiovascular responses on heart rate and not to an age-related reduction in cardiac β-adrenergic sensitivity. Endurance training is not associated with altered β-adrenergic chronotropic sensitivity in the elderly. The transient pressor response to intravenously administered clonidine may be lost in ageing man.

scholarly journals Arginine behaviour after arginine or citrulline administration in older subjects

2015 ◽  
Vol 115 (3) ◽  
pp. 399-404 ◽  
Author(s):  
C. Moinard ◽  
J. Maccario ◽  
S. Walrand ◽  
V. Lasserre ◽  
J. Marc ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
The Elderly ◽  
Volume Of Distribution ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Age Related ◽  
Loading Tests ◽  
Kinetics Of ◽  
Healthy Elderly Subjects

AbstractArginine (ARG) and its precursor citrulline (CIT) are popular dietary supplements, especially for the elderly. However, age-related reductions in lean body mass and alterations in organ functions could change their bioavailability. Pharmacokinetics and tolerance to amino acid (AA) loads are poorly documented in elderly subjects. The objective here was to characterise the plasma kinetics of CIT and ARG in a single-dosing study design. Eight fasting elderly men underwent two separate isomolar oral loading tests (10 g of CIT or 9·94 g of ARG). Blood was withdrawn over an 8-h period to measure plasma AA concentrations. Only CIT, ornithine and ARG plasma concentrations were changed. Volume of distribution was not dependent on AA administered. Conversely, parameters related to ARG kinetics were strongly dependent on AA administered: after ARG load, elimination was higher (ARG>CIT; P=0·041) and admission period+time at peak concentration was lower (ARG<CIT; P=0·033), and the combination of both phenomena results in a marked increase in ARG availability when CIT was administered (ARG<CIT; P=0·033) compared with ARG administration itself. In conclusion, a single CIT administration in the elderly is safe and well tolerated, and CIT proves to be a better in vivo ARG precursor than ARG itself in healthy elderly subjects.

scholarly journals Mitochondrial Adaptations in Aged Skeletal Muscle: Effect of Exercise Training

2017 ◽  
pp. 1-14 ◽  
Author(s):  
M. M. ZIAALDINI ◽  
S. R. A. HOSSEINI ◽  
M. FATHI
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Mitochondrial Function ◽  
The Elderly ◽  
Elderly Subjects ◽  
Cellular Mechanisms ◽  
Healthy Elderly ◽  
Mitochondrial Functions ◽  
Healthy Elderly Subjects ◽  
Mitochondrial Adaptations

The aging process is associated with a decline in mitochondrial functions. Mitochondria dysfunction is involved in initiation and progression of many health problems including neuromuscular, metabolic and cardiovascular diseases. It is well known that endurance exercise improves mitochondrial function, especially in the elderly. However, recent studies have demonstrated that resistance training lead also to substantial increases in mitochondrial function in skeletal muscle. A comprehensive understanding of the cellular mechanisms involved in the skeletal muscle mitochondrial adaptations to exercise training in healthy elderly subjects, can help practitioners to design and prescribe more effective exercise trainings.

Effect of aging on susceptibility of low-density lipoproteins to oxidation

1995 ◽  
Vol 41 (11) ◽  
pp. 1628-1632 ◽  
Author(s):  
A Schmuck ◽  
C J Fuller ◽  
S Devaraj ◽  
I Jialal
Keyword(s):  
Time Course ◽  
Lipid Peroxides ◽  
Beta Carotene ◽  
The Elderly ◽  
Alpha Tocopherol ◽  
Ldl Oxidation ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Kinetics Of ◽  
Healthy Elderly Subjects

Abstract According to the Adult Treatment Panel of the National Cholesterol Education Program, age is a major risk factor for heart disease. To assess the relation between age and LDL oxidizability, we studied copper-mediated LDL oxidation in 13 healthy elderly subjects (&gt; 59 years) and 13 sex-matched healthy young controls (&lt; 30 years). Total and LDL-cholesterol concentrations were increased in elderly subjects. The time course of copper-mediated LDL oxidation showed no significant differences between the two groups as assessed by formation of conjugated dienes, lipid peroxides, and apolipoprotein B fluorescence. Kinetics of LDL oxidation as quantified by lag time, oxidation rate, and maximal oxidation were not significantly different between the elderly and young groups. Although the concentrations of 16:0, 18:0, 18:1, 18:3, and 20:4 and total polyunsaturated fatty acids were significantly higher in the elderly group, LDL fatty acid concentrations were similar in both groups. Lipid-standardized alpha-tocopherol, beta-carotene, and ascorbate concentrations were not significantly different between the two groups. The findings of the present study suggest that in the healthy elderly, LDL oxidation may not be a crucial mediator for atherogenesis.

scholarly journals Impact of Aging on Urinary Excretion of Iron and Zinc

2014 ◽  
Vol 7 ◽  
pp. NMI.S12977 ◽  
Author(s):  
Karina Pfrimer ◽  
Rutinéia Fátima Micheletto ◽  
Julio Sergio Marchini ◽  
Gilberto João Padovan ◽  
Julio cesar Moriguti ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Graphite Furnace ◽  
The Elderly ◽  
Atomic Absorption Spectrophotometry ◽  
Elderly Subjects ◽  
Fasting Period ◽  
Younger Adults ◽  
Healthy Elderly ◽  
Iron And Zinc ◽  
Healthy Elderly Subjects

Project Data about the influence of aging on urinary excretion of iron and zinc are scarce. The objective of the present study was to compare the concentration of zinc and iron in the urine of healthy elderly subjects and younger adults. Procedure Seven healthy elderly subjects and seven younger adults were selected and submitted to biochemical, clinical, and nutritional tests. After a fasting period, 12-hour urine was collected for the determination of iron and zinc concentrations by graphite furnace atomic absorption spectrophotometry. Results Urinary zinc and iron concentrations of the elderly subjects were not significantly different from that of younger adults. However, the total zinc and iron urinary clearance in 24 hours for the elderly was significantly higher compared with that of younger adults. Conclusion There is an increase in urinary iron and zinc clearance with aging. The values reported in this manuscript may be used as references in future studies.

Nonexercise movement in elderly compared with young people

2007 ◽  
Vol 292 (4) ◽  
pp. E1207-E1212 ◽  
Author(s):  
Ann M. Harris ◽  
Lorraine M. Lanningham-Foster ◽  
Shelly K. McCrady ◽  
James A. Levine
Keyword(s):  
Energy Expenditure ◽  
Lean Body Mass ◽  
Body Mass ◽  
The Elderly ◽  
Energetic Cost ◽  
Elderly Subjects ◽  
Older Individuals ◽  
Free Living ◽  
Healthy Elderly ◽  
Young Subjects

The association between free-living daily activity and aging is unclear because nonexercise movement and its energetic equivalent, nonexercise activity thermogenesis, have not been exhaustively studied in the elderly. We wanted to address the hypothesis that free-living nonexercise movement is lower in older individuals compared with younger controls matched for lean body mass. Ten lean, healthy, sedentary elderly and 10 young subjects matched for lean body mass underwent measurements of nonexercise movement and body posture over 10 days using sensitive, validated technology. In addition, energy expenditure was assessed using doubly labeled water and indirect calorimetry. Total nonexercise movement (acceleration arbitrary units), standing time, and standing acceleration were significantly lower in the elderly subjects; this was specifically because the elderly walked less distance per day despite having a similar number of walking bouts per day compared with the young individuals. The energetic cost of basal metabolic rate, thermic effect of food, total daily energy expenditure, and nonexercise activity thermogenesis were not different between the elderly and young groups. Thus, the energetic cost of walking in the elderly may be greater than in the young. Lean, healthy elderly individuals may have a biological drive to be less active than the young.

scholarly journals Communication map of elderly people: Sociodemographic and cognitive-linguistic aspects

2013 ◽  
Vol 7 (4) ◽  
pp. 380-386
Author(s):  
Marcela Lima Silagi ◽  
Aline Rufo Peres ◽  
Eliane Schochat ◽  
Leticia Lessa Mansur
Keyword(s):  
Verbal Fluency ◽  
The Elderly ◽  
Sociodemographic Factors ◽  
Elderly Subjects ◽  
Auditory Comprehension ◽  
Cognitive Screening ◽  
Healthy Elderly ◽  
Token Test ◽  
Tip Of The Tongue ◽  
Healthy Elderly Subjects

ABSTRACT Language and communication difficulties may occur in the elderly population. This is the case of the tip-of-the-tongue phenomenon and receptive and auditory comprehension difficulties. Few studies have focused on examining the effects of social exposure on maintaining communication in the aging process. Objectives: [1] To describe the communication map of healthy elderly subjects; [2] To search for associations between frequency and time dedicated to communication and cognitive and sociodemographic factors. Methods: Healthy elderly subjects were submitted to cognitive screening, the Token Test - Revised, and the Verbal Fluency test, and answered the ASHA-FACS and the Circles of Communication Partners questionnaires. Results: 55 subjects, 67% female, with ages over 60 years and varied schooling were included in the sample. Interlocutors in the circle of close friends and acquaintances predominated in the communication map, although the time devoted to communication with these partners was lower than in other circles. Overall, the elderly reported no deficits in language comprehension, with some reports of the tip-of-the-tongue phenomenon. Poor performances on the Token Test - Revised and in phonemic verbal fluency along with reports of communication functionality indicated that these subjects compensate for their problems. Conclusion: Older subjects with lower schooling tended to predominantly communicate within the family circle. Within other circles, the number of hours devoted to communication and dialogue partners was not associated with age or schooling. The time devoted to the circle of communication with friends may indicate cognitive difficulties.

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