Haemodynamic Responses in Young and Elderly, Healthy Subjects during Ambient and Warm Head-up Tilt

1998 ◽  
Vol 94 (5) ◽  
pp. 493-498 ◽  
Author(s):  
Michael Lye ◽  
Tom Walley
Keyword(s):  
Skin Temperature ◽  
Postural Hypotension ◽  
The Elderly ◽  
Young Group ◽  
Elderly Subjects ◽  
Healthy Elderly ◽  
Head Up Tilt ◽  
Blood Pressures ◽  
Young Subjects ◽  
Qualitative Responses

1. Postural hypotension is common in elderly people and is usually multifactorial in origin. In young subjects increased ambient temperature is associated with postural symptoms. We hypothesized that such increases in skin temperature due to the use of bed clothes might contribute to nocturnal postural hypotension in the elderly. We therefore studied haemodynamic responses to head-up tilt in healthy elderly and young subjects, with and without passive heating induced by covering with blankets. 2. Nine young (28.7 ± 1.5 years; mean ± S.E.M.) and nine elderly (71.9 ± 1.8 years) subjects were studied. All had been carefully screened to exclude factors likely to affect responses to tilt. All subjects underwent a standard head-up tilt procedure at ambient room temperature while haemodynamic responses were monitored. The subjects were then covered in blankets for 55 min and the tilt repeated. Skin temperature before the second tilt had increased from approximately 32.5 °C to approximately 35.2 °C (P < 0.001). 3. The elderly subjects maintained higher blood pressures throughout both tilts (P < 0.001) and both groups showed similar qualitative responses to tilt. Supine heart rates were higher in the elderly group (P < 0.01) with a tendency to increase more in the young group in response to tilt, especially while warm (P = 0.370). Stroke volumes and cardiac indices were consistently higher in the young group who showed larger changes during both head-up tilts. In both groups the haemodynamic responses to ambient and warm tilt were essentially the same. 4. Healthy elderly subjects, who are carefully screened to exclude individuals with cardiovascular pathology, respond to head-up tilt in the same qualitative fashion as young subjects. Quantitative responses in older subjects are ‘damped’. Short-term natural body warming does not impair the reflexes in young or old subjects.

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.

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.

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.

Investigation of the Effect of Weighting between sEMG and Interaction Force in Intention Extraction for the Control of an Upper-Limb Assistive Device

2017 ◽  
Vol 02 (02) ◽  
pp. 1740005
Author(s):  
Sangjoon J. Kim ◽  
Hyosang Lee ◽  
Jung Kim
Keyword(s):  
Upper Limb ◽  
The Elderly ◽  
Interaction Force ◽  
Young Group ◽  
Assistive Device ◽  
Elderly Subjects ◽  
User Intention ◽  
Young Subjects ◽  
Point To Point ◽  
Muscular Effort

We investigated the effect of the weighting between surface electromyography (sEMG) and interaction force for user intention extraction for the control of an upper-limb assistive device. A point-to-point vertical arm lifting task was performed by two age-segregated cohorts including 10 young subjects and 10 elderly subjects. The performance in terms of muscular effort and repeatability was analyzed. The elderly and young group showed age-dependent differences in terms of muscular effort with distinct sEMG weights.

scholarly journals Renal functional reserve in healthy elderly subjects.

1993 ◽  
Vol 3 (7) ◽  
pp. 1371-1377
Author(s):  
D Fliser ◽  
M Zeier ◽  
R Nowack ◽  
E Ritz
Keyword(s):  
Renal Disease ◽  
The Elderly ◽  
Renal Hemodynamics ◽  
Elderly Subjects ◽  
Functional Reserve ◽  
Renal Functional Reserve ◽  
Healthy Elderly ◽  
Age Related ◽  
Before And After ◽  
Young Subjects

The increase in GFR after an amino acid (AA) load, the so-called renal functional reserve, is impaired in the aged rat. Whether the renal functional reserve predicts the progression of renal disease in humans is controversial, but it is possible that age-related alterations of renal hemodynamics are relevant for the evolution of renal disease in the elderly. We compared renal hemodynamics before and after an AA infusion in 15 healthy normotensive subjects of young age (seven women, eight men; median age, 26 yr; range, 23 to 32) and in 10 subjects of old age (six women, four men; median age, 70 yr; range, 61 to 82) on normal dietary protein intake. Baseline GFR and effective RPF were measured after 12 h of fasting by the inulin (Cin) and para-aminohippurate (Cpah) steady-state infusion techniques. The renal functional reserve was examined after an overnight AA infusion (7% solution; 83 mL/h). Median basal Cin and Cpah were significantly lower (P < 0.01) in the elderly (102 and 339 mL/min per 1.73 m2) than in the young subjects (122 and 647 mL/min per 1.73 m2), but virtually all GFR values of the elderly were still within the normal range. Median Cin upon infusion of AA was 118 mL/min per 1.73 m2 (range, 98 to 137) in the elderly and 146 (range, 120 to 171) in the young, respectively. Corresponding values of Cpah were 349 mL/min per 1.73 m2 in the elderly versus 689 mL/min per 1.73 m2 in the young. Cin increased significantly (P < 0.01) after the AA load in both young and elderly subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Maximal skin blood flow is decreased in elderly men

1994 ◽  
Vol 77 (1) ◽  
pp. 11-14 ◽  
Author(s):  
G. A. Rooke ◽  
M. V. Savage ◽  
G. L. Brengelmann
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Skin Blood Flow ◽  
Local Heating ◽  
The Elderly ◽  
Elderly Subjects ◽  
Elderly Men ◽  
Blood Flows ◽  
Age Related ◽  
Young Subjects

When subjected to total body heating and exercise, skin blood flow does not increase as much in elderly as in young subjects. It is not known whether this age-related decline is due to the autonomic dysfunction that develops in the elderly or to changes at the level of the blood vessels of the skin. We used local heating of the forearm to quantify the intrinsic ability of the cutaneous vasculature to dilate in seven young men (avg age 31 yr) and seven elderly men (avg age 71 yr). A water spray was used to maintain a neutral skin temperature of 32–35 degrees C for > 10 min, followed by 60 min of a 42 degrees C skin temperature to induce maximal skin blood flow. Forearm blood flow was measured by venous occlusion plethysmography with a mercury-in-Silastic circumference gauge. At the neutral skin temperature, forearm blood flows in the elderly subjects were comparable to those in the young subjects: 3.0 +/- 0.5 vs. 2.8 +/- 1.0 ml.min-1 x 100 ml-1. During the last 10 min of heating, however, blood flows were much lower in the elderly than in the young subjects: 11.1 +/- 2.7 vs. 19.9 +/- 5.2 ml.min-1 x 100 ml-1 (P = 0.002). We conclude that aging results in a reduction of the maximal conductance of the cutaneous vasculature.

Association between trait anxiety and endothelial function observed in elderly males but not in young males

2006 ◽  
Vol 19 (5) ◽  
pp. 947-954 ◽  
Author(s):  
Kosuke Narita ◽  
Tetsuhito Murata ◽  
Toshihiko Hamada ◽  
Tetsuya Takahashi ◽  
Hirotaka Kosaka ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Trait Anxiety ◽  
Clinical Manifestations ◽  
Young Male ◽  
The Elderly ◽  
Elderly Subjects ◽  
Elderly Male ◽  
Healthy Elderly ◽  
Atherosclerotic Lesions ◽  
Young Subjects

Background and objectives: Endothelial function plays a key role in determining the clinical manifestations of atherosclerosis. Recent reports have shown that healthy elderly subjects with higher trait anxiety tend to have heightened risks of atherosclerotic lesions and cardiovascular disease. The present study was intended to examine whether an association exists between trait anxiety and endothelial function in healthy young and elderly subjects.Methods: This study examined 26 young male and 30 elderly male subjects using brachial artery flow-mediated dilation (FMD) – a non-invasive ultrasound method – to evaluate endothelial function by measuring the dilation responses of vascular smooth muscle to the nitric oxide produced by endothelial cells following hyperemia.Results: A significant negative correlation was observed between the State and Trait Anxiety Inventory (STAI)-trait score as a parameter of anxiety and the percentage change of FMD (%FMD) in the elderly subjects, but not in the young subjects. The elderly subjects showed significantly lower %FMD than the young subjects.Conclusion: These results suggest the possibility that trait anxiety is a predisposing risk factor for cardiovascular damage that might, over a long period, induce atherosclerotic lesions.

The BOLD Hemodynamic Response in Healthy Aging

2004 ◽  
Vol 16 (5) ◽  
pp. 786-793 ◽  
Author(s):  
Howard J. Aizenstein ◽  
Kristi A. Clark ◽  
Meryl A. Butters ◽  
Jennifer Cochran ◽  
V. Andrew Stenger ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Healthy Aging ◽  
Functional Neuroimaging ◽  
The Elderly ◽  
Hemodynamic Response ◽  
Elderly Subjects ◽  
Bold Response ◽  
Healthy Elderly ◽  
Young Subjects

Several previous studies have compared the blood oxygen level-dependent (BOLD) hemodynamic response (HDR) in healthy elderly subjects to the HDR in young subjects. Some studies have found a relative decreased amplitude in the elderly in the visual cortex, whereas other studies have found the elderly HDR amplitude in the visual cortex to be nearly identical to that in young subjects. A possible explanation for the different findings is that the peak voxel HDR is similar between the groups, but that the HDR in the group-averaged region-of-interest (ROI) is “washed out” by the inclusion of less significant voxels (due to a smaller extent of activation in the elderly) or by the inclusion of negative-peaking voxels. We tested this hypothesis using event-related functional magnetic resonance imaging (fMRI). While undergoing fMRI, subjects performed a simple visual and motor task, pressing with their index fingers in response to visual presentation of the word tap. Data from 18 subjects, 8 young and 10 elderly, were analyzed. For each subject, a visual and a motor ROI was selected by choosing the most significant positive voxels within the anatomically defined ROI. This individual subject approach excluded both low-significance and negative-peaking voxels. Similar peaks were found for the elderly and the young subjects in both motor and visual regions and a more sustained BOLD response was found for the elderly in both regions. Additionally, as predicted, a greater percentage of voxels with a negative HDR was found for the elderly in the visual region; this finding was also replicated in our reanalysis of an independent fMRI and aging study from the fMRI Data Center. Functional neuroimaging observations of negative HDRs in visual areas have been interpreted as the effect of unconstrained processing during rest. Our results suggest that the elderly may have more unconstrained visual processing during the rest condition in the scanner. The observation that the group differences in the BOLD response are sensitive to voxel selection (e.g., inclusion of low-significance and/or negative voxels) underscores the importance of ROI selection criteria in the interpretation of fMRI studies using elderly populations.

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