Effects of aging on sensation of respiratory force and displacement

The psychophysical technique of magnitude production was used to evaluate the sensation of inspiratory force and inspired volume in young and older subjects. Inspiratory force was generated during a static inspiratory maneuver against a closed airway. The exponent of the power function relationship between airway pressure and sensation intensity during force scaling was not significantly different between young and older subjects. In contrast, the exponents for the magnitude production of inspired volume were significantly greater in the older compared with the young group. We also assessed the effects of age on the relative importance of force and displacement signals on the sensation of inspired volume. Subjects attempted to reproduce a control tidal volume while breathing against a series of inspiratory resistive and elastic loads. In both groups error in tidal volume reproduction increased progressively as the severity of the load increased. During moderate and severe loading the error in the older subjects was significantly greater than in the young group. Correspondingly, the peak inspiratory airway pressures at tidal volume reproduction against these loads were significantly smaller in the older compared with the young subjects. The results suggest that in older subjects cues related to respiratory muscle force are more important than volume in the sensation of lung volume changes. In young subjects the sensation of lung volume changes is based to a greater degree on signals of volume or displacement.

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Effect of changes in lung volume on respiratory system compliance in newborn infants

Journal of Applied Physiology ◽

10.1152/jappl.1989.67.3.1192 ◽

1989 ◽

Vol 67 (3) ◽

pp. 1192-1197 ◽

Cited By ~ 14

Author(s):

F. Ratjen ◽

R. Zinman ◽

A. R. Stark ◽

L. E. Leszczynski ◽

M. E. Wohl

Keyword(s):

Tidal Volume ◽

Respiratory System ◽

Lung Volume ◽

Newborn Infants ◽

Face Mask ◽

Flow Volume ◽

Respiratory System Compliance ◽

Tidal Breathing ◽

Volume Changes ◽

Passive Flow

Total respiratory system compliance (Crs) at volumes above the tidal volume (VT) was studied by use of the expiratory volume clamping (EVC) technique in 10 healthy sleeping unsedated newborn infants. Flow was measured with a pneumotachograph attached to a face mask and integrated to yield volume. Volume changes were confirmed by respiratory inductance plethysmography. Crs measured by EVC was compared with Crs during tidal breathing determined by the passive flow-volume (PFV) technique. Volume increases of approximately 75% VT were achieved with three to eight inspiratory efforts during expiratory occlusions. Crs above VT was consistently greater than during tidal breathing (P less than 0.0005). This increase in Crs likely reflects recruitment of lung units that are closed or atelectatic in the VT range. Within the VT range, Crs measured by PFV was compared with that obtained by the multiple-occlusion method (MO). PFV yielded greater values of Crs than MO (P less than 0.01). This may be due to braking of expiratory airflow after the release of an occlusion or nonlinearity of Crs. Thus both volume recruitment and airflow retardation may affect the measurement of Crs in unsedated newborn infants.

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Rho kinase-mediated local cold-induced cutaneous vasoconstriction is augmented in aged human skin

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00152.2007 ◽

2007 ◽

Vol 293 (1) ◽

pp. H30-H36 ◽

Cited By ~ 41

Author(s):

Caitlin S. Thompson-Torgerson ◽

Lacy A. Holowatz ◽

Nicholas A. Flavahan ◽

W. Larry Kenney

Keyword(s):

Rho Kinase ◽

Age Difference ◽

Local Cooling ◽

Kinase Inhibition ◽

Doppler Flowmetry ◽

Forearm Skin ◽

Older Subjects ◽

Young Subjects ◽

Effects Of Aging ◽

Cutaneous Vasoconstriction

Cutaneous vasoconstriction (VC), a critical thermoregulatory response to cold, is generally impaired with aging. However, the effects of aging on local cooling-induced VC and its underlying mechanisms are poorly understood. We tested whether aged skin exhibits attenuated localized cold-induced VC and whether Rho kinase-mediated cold-induced VC is augmented with age. Skin blood flow was monitored with laser Doppler flowmetry (LDF) on seven young and seven older subjects. Cutaneous vascular conductance (CVC; LDF/mean arterial pressure) was expressed as percentage change from baseline (%ΔCVCbase). In protocol 1, two forearm skin sites were cooled to six temperatures (31.5–19°C) for 10 min each or two temperatures (29°C, 24°C) for 30 min each, with no age differences in the magnitude of VC. In protocol 2, three forearm skin sites were instrumented for intradermal microdialysis and cooled to 24°C for 40 min. During minutes 1–5, there was no age difference in CVC responses at control sites (young: −45 ± 6% vs. older: −46 ± 3%, P > 0.9). Adrenoceptor antagonism (yohimbine + propranolol) abolished VC in young (to +15 ± 13%, P < 0.05) but only partially inhibited VC in older subjects (to −23 ± 6%, P < 0.05). Rho kinase inhibition plus adrenoceptor antagonism (yohimbine + propranolol + fasudil) abolished VC in both groups. During minutes 35–40, there was no age difference in control (young: −77 ± 4% vs. older: −70 ± 2%, P > 0.3) or adrenoceptor-antagonized responses (young: −61 ± 3% vs. older: −55 ± 2%, P > 0.3); however, Rho kinase inhibition plus adrenoceptor antagonism blocked more VC in older compared with young subjects (−19 ± 11% vs. −35 ± 3%, P < 0.05). Although its magnitude remains unaffected, cold-induced VC becomes less dependent on adrenergic and more dependent on Rho kinase signaling with advancing age.

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Regulation of frequency and depth of breathing during expiratory threshold loading in cats

Journal of Applied Physiology ◽

10.1152/jappl.1975.38.5.869 ◽

1975 ◽

Vol 38 (5) ◽

pp. 869-874 ◽

Cited By ~ 16

Author(s):

M. M. Grunstein ◽

I. Wyszogrodski ◽

J. Milic-Emili

Keyword(s):

Tidal Volume ◽

Lung Volume ◽

The Other ◽

Spontaneous Ventilation ◽

Volume Changes ◽

Phasic Component ◽

Stretch Receptors ◽

Pulmonary Stretch Receptors ◽

The Absolute ◽

Spontaneously Breathing

In six spontaneously breathing anesthetized cats, intermittently subjected to inspiratory elastic loads, we have studied the relationships between tidal volume (VT) and the durations of inspiration (Ti) and breath duration (Ttot) obtained during spontaneous ventilation from resting lung volume (FRCc) and from elevated end-expiratory levels. The latter was elevated by submerging the expiratory breathing line into a column of water, representing the addition of an expiratory threshold load (ETL). The VT vs. Ti relationships obtained at different end-expiratory levels were similar, indicating that during ETL the vagal mechanism regulating Ti responds only to lung volume changes above the new end-expiratory level and is independent of the absolute end-expiratory lung volume. Single vagal fiber recordings suggest that this effect on Ti control may be explained on the basis of adaptation occurring at the level of the pulmonary stretch receptors. The control of Ttot, on the other hand, was found to depend both on the Ti of the preceding breath (phasic component) and on a separate vagal mechanism specifically affecting the duration of expiration (Te) in response to changes in the absolute end-expiratory lung volume. The latter mechanism is functionally inoperative at FRCc.

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The effect of body mass and sex on the accuracy of respiratory magnetometers for measurement of end-expiratory lung volumes

Journal of Applied Physiology ◽

10.1152/japplphysiol.00571.2016 ◽

2016 ◽

Vol 121 (5) ◽

pp. 1169-1177 ◽

Cited By ~ 4

Author(s):

Joanne Avraam ◽

Rosie Bourke ◽

John Trinder ◽

Christian L. Nicholas ◽

Danny Brazzale ◽

...

Keyword(s):

Tidal Volume ◽

Body Mass ◽

Lung Volume ◽

Normal Weight ◽

Volume Changes ◽

Obstructive Sleep ◽

Target Volumes ◽

Healthy Obese ◽

Magnetometer Calibration ◽

Calibration Techniques

Respiratory magnetometers are increasingly being used in sleep studies to measure changes in end-expiratory lung volume (EELV), including in obese obstructive sleep apnea patients. Despite this, the accuracy of magnetometers has not been confirmed in obese patients nor compared between sexes. Thus we compared spirometer-measured and magnetometer-estimated lung volume and tidal volume changes during voluntary end-expiratory lung volume changes of 1.5, 1, and 0.5 l above and 0.5 l below functional respiratory capacity in supine normal-weight [body mass index (BMI) < 25 kg/m] and healthy obese (BMI > 30 kg/m) men and women. Two different magnetometer calibration techniques proposed by Banzett et al. [Banzett RB, Mahan ST, Garner DM, Brughera A, Loring SH. J Appl Physiol (1985) 79: 2169–2176, 1995] and Sackner et al. [Sackner MA, Watson H, Belsito AS, Feinerman D, Suarez M, Gonzalez G, Bizousky F, Krieger B. J Appl Physiol (1985) 66: 410–420, 1989] were assessed. Across all groups and target volumes, magnetometers overestimated spirometer-measured EELV by ~65 ml (<0.001) with no difference between techniques (0.07). The Banzett method overestimated the spirometer EELV change in normal-weight women for all target volumes except +0.5 l, whereas no differences between mass or sex groups were observed for the Sackner technique. The variability of breath-to-breath measures of EELV was significantly higher for obese compared with nonobese subjects and was higher for the Sackner than Banzett technique. On the other hand, for tidal volume, both calibration techniques underestimated spirometer measurements (<0.001), with the underestimation being more marked for the Banzett than Sackner technique (0.03), in obese than normal weight (<0.001) and in men than in women (0.003). These results indicate that both body mass and sex affect the accuracy of respiratory magnetometers in measuring EELV and tidal volume.

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Protein and carbohydrate supplementation after exercise increases plasma volume and albumin content in older and young men

Journal of Applied Physiology ◽

10.1152/japplphysiol.91264.2008 ◽

2009 ◽

Vol 107 (3) ◽

pp. 770-779 ◽

Cited By ~ 37

Author(s):

Kazunobu Okazaki ◽

Hideki Hayase ◽

Takashi Ichinose ◽

Hiroyuki Mitono ◽

Tatsuya Doi ◽

...

Keyword(s):

G Protein ◽

Plasma Volume ◽

Age Groups ◽

Young Group ◽

Fluid Volume ◽

Peak Oxygen Consumption ◽

Albumin Content ◽

Older Subjects ◽

Young Subjects ◽

Total Fluid

This study examined whether increased plasma volume (PV) and albumin content (Albcont) in plasma for 23 h after exercise were attenuated in older subjects compared with in young adult subjects, and if this attenuation abated by supplementation with protein and carbohydrate (CHO) immediately after exercise. Eight moderately active older (∼68 yr) and 8 young (∼21 yr) men performed two trials: control (CNT) and Pro-CHO in which subjects consumed placebo (0.5 kcal, 0 g protein, 0.5 mg Na+ in 3.2 ml total fluid volume/kg body wt) or protein and CHO mixture (3.2 kcal, 0.18 g protein, 0.5 mg Na+ in 3.2 ml total fluid volume/kg body wt) supplementations, respectively, immediately after high-intensity interval exercise for 72 min [8 sets of 4 min at 70–80% peak oxygen consumption rate (V̇o2peak) intermitted by 5 min at 20% V̇o2peak]. PV, Albcont, and plasma globulin content (Glbcont) were measured before exercise, at the end of exercise, every hour from the 1st to the 5th hour after exercise, and at the 23rd hour after exercise. From 12 h before the start to the end of experiment, food intake was controlled to the age-matched recommended dietary allowances. We found that during the first 4 h after exercise in CNT, Albcont recovered less in the older than the young group by ∼0.04 g/kg ( P < 0.05), while it generally recovered more with Pro-CHO than CNT by ∼0.09 and ∼0.04 g/kg in the young and older group, respectively, accompanied by a greater increase in PV by ∼1 and ∼2 ml/kg, respectively, during the 23 h after exercise ( P < 0.05). Glbcont remained constant throughout the experiment in both trials for both age groups. Thus the attenuated responses of Albcont and PV after exercise in older subjects were restored by protein and CHO supplementation immediately after exercise, similarly to young subjects.

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Modulatory Effects of Levodopa on Cognitive Control in Young but not in Older Subjects: A Pharmacological fMRI Study

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2011.21603 ◽

2011 ◽

Vol 23 (10) ◽

pp. 2797-2810 ◽

Cited By ~ 24

Author(s):

Özgür A. Onur ◽

Martina Piefke ◽

Chuh-Hyoun Lie ◽

Christiane M. Thiel ◽

Gereon R. Fink

Keyword(s):

Age Groups ◽

Older Individuals ◽

Interference Control ◽

Double Blind ◽

Older Volunteers ◽

Visual Spatial ◽

Older Subjects ◽

Young Subjects ◽

Spatial Interference ◽

Effects Of Aging

Older individuals show decline of prefrontal cortex (PFC) functions which may be related to altered dopaminergic neurotransmission. We investigated the effects of aging and dopaminergic stimulation in 15 young and 13 older healthy subjects on the neural correlates of interference control using fMRI. In a double-blind, placebo-controlled within-subject design, subjects were measured after levodopa (100 mg) or placebo administration. In each session, subjects performed a visual–spatial interference task based on a Stroop/Simon-like paradigm. Across age groups, interference (incongruent relative to congruent trials) was associated with activations in the presupplementary motor area, ACC, and intraparietal cortex. Increased interference was found behaviorally in older volunteers. Differential activation in left dorsolateral PFC in young subjects and bilateral PFC activity in older subjects was observed to be associated with interference control. Performance deteriorated under levodopa only in young subjects. This was accompanied by an increase of neural activity in ACC (p < .05; small-volume correction for multiple comparisons). Worsening of performance under levodopa in young subjects and the associated effect on ACC may indicate that overstimulation of the dopaminergic system compromises interference control. This supports the inverted-U-shaped model of neurotransmitter action.

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Effects of Aging on Feedforward Postural Synergies

Journal of Human Kinetics ◽

10.2478/v10078-008-0018-6 ◽

2008 ◽

Vol 20 (1) ◽

pp. 63-70 ◽

Cited By ~ 11

Author(s):

Tadayoshi Asaka ◽

Yun Wang

Keyword(s):

Time Lag ◽

Principal Component ◽

Young Group ◽

Co Activation ◽

Extensor Muscles ◽

Postural Muscle ◽

Older Subjects ◽

Effects Of Aging ◽

Postural Synergies ◽

Muscle Modes

Effects of Aging on Feedforward Postural SynergiesWe investigated the effects of aging on postural muscles covariate patterns prior to voluntary perturbations. Nine healthy young and nine older subjects were instructed to release a load in a self-paced manner. The results of cross-correlation analyses showed that the average time lag corresponding peak correlation coefficient between trunk flexor and extensor muscles in the older group was significantly shorter, compared to that in the young group. The results of principal component analysis showed that the co-contraction Muscle-modes in the older group were observed more frequently than those in the young group. These results indicate that the older group showed changes in the anticipatory postural muscle co-variation, suggesting the transition from reciprocal to co-activation pattern with aging.

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Pulmonary nitrogen clearance in relation to age in healthy males

Journal of Applied Physiology ◽

10.1152/jappl.1963.18.2.297 ◽

1963 ◽

Vol 18 (2) ◽

pp. 297-300 ◽

Cited By ~ 25

Author(s):

Arend Bouhuys

Keyword(s):

Tobacco Smoke ◽

Lung Volume ◽

Long Term Effects ◽

Gas Distribution ◽

Volume Changes ◽

Lung Volumes ◽

Physiological Consequence ◽

Older Subjects ◽

Healthy Males

Lung volumes and N2 clearance during O2 breathing were recorded in 80 healthy males, 24–65 years of age. Lung volume changes with age were similar to those found in other studies. Uneven distribution of inspired gas in the lungs as estimated from N2 clearance data showed relatively small changes with age, and the range of variability of these data was larger among the older subjects. The results suggest that impaired intrapulmonary gas distribution in older subjects is not a physiological consequence of aging, but may rather be related to long-term effects of inhaled noxious agents such as tobacco smoke. Submitted on June 11, 1962

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Different Effects of Aging on Intraocular Pressures Measured by Three Different Tonometers

Journal of Clinical Medicine ◽

10.3390/jcm10184202 ◽

2021 ◽

Vol 10 (18) ◽

pp. 4202

Author(s):

Kazunobu Sugihara ◽

Masaki Tanito

Keyword(s):

Linear Regression ◽

Regression Models ◽

Corneal Thickness ◽

Regression Analyses ◽

Mixed Effect ◽

Effect Regression ◽

Older Subjects ◽

Young Subjects ◽

Highly Correlated ◽

Effects Of Aging

This study aimed to compare intraocular pressures (IOP) using different tonometers, Goldmann applanation (IOPGAT), non-contact (IOPNCT), and rebound (IOPRBT), and to assess the effects of aging and central corneal thickness (CCT) on the measurements. The IOPGAT, IOPNCT, IOPRBT, mean patient age (65.1 ± 16.2 years), and CCT (521.7 ± 39.2 µm) were collected retrospectively from 1054 eyes. The differences among IOPs were compared by the paired t-test. Possible correlations between devices, age, and CCT were assessed by linear regression analyses. The effects of age and CCT on the IOP reading were assessed by mixed-effects regression models. The IOPGAT values were 2.4 and 1.4 mmHg higher than IOPNCT and IOPRBT, respectively; the IOPNCT was 1.0 mmHg lower than IOPRBT (p < 0.0001 for all comparisons). The IOPs measured by each tonometer were highly correlated with each other (r = 0.81–0.90, t = 45.2–65.5). The linear regression analyses showed that age was negatively correlated with IOPNCT (r = −0.12, t = −4.0) and IOPRBT (r = −0.14, t = −4.5) but not IOPGAT (r = 0.00, t = −0.2); the CCT was positively correlated with IOPGAT (r = 0.13, t = 4.3), IOPNCT (r = 0.29, t = 9.8), and IOPRBT (r = 0.22, t = 7.2). The mixed-effect regression models showed significant negative correlations between age and IOPNCT (t = −2.6) and IOPRBT (t = −3.4), no correlation between age and IOPGAT (t = 0.2), and a significant positive correlation between CCT and the tonometers (t = 3.4–7.3). No differences between IOPGAT and IOPRBT were seen at the age of 38.8 years. CCT affects IOPs from all tonometers; age affects IOPNCT and IOPRBT in different degrees. IOPRBT tended to be higher than IOPGAT in young subjects, but this stabilized in middle age and became higher in older subjects.

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