Effect of aging on ventilatory response to exercise and CO2

1984 ◽  
Vol 56 (5) ◽  
pp. 1143-1150 ◽  
Author(s):  
M. J. Brischetto ◽  
R. P. Millman ◽  
D. D. Peterson ◽  
D. A. Silage ◽  
A. I. Pack
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Work Load ◽  
The Elderly ◽  
Co2 Production ◽  
Elderly Subjects ◽  
Control Group ◽  
Effects Of Aging ◽  
Response To Exercise ◽  
The Relationship

Studies were performed to determine the effects of aging on the ventilatory responsiveness to two known respiratory stimulants, inhaled CO2 and exercise. Although explanation of the physiological mechanisms underlying development of exercise hyperpnea remains elusive, there is much circumstantial evidence that during exercise, however mediated, ventilation is coupled to CO2 production. Thus matched groups of young and elderly subjects were studied to determine the relationship between increasing ventilation and increasing CO2 production (VCO2) during steady-state exercise and the change in their minute ventilation in response to progressive hypercapnia during CO2 rebreathing. We found that the slope of the ventilatory response to hypercapnia was depressed in elderly subjects when compared with the younger control group (delta VE/delta PCO2 = 1.64 +/- 0.21 vs. 2.44 +/- 0.40 l X min-1 X mmHg-1, means +/- SE, respectively). In contrast, the slope of the relationship between ventilation and CO2 production during exercise in the elderly was greater than that of younger subjects (delta VE/delta VCO2 = 29.7 +/- 1.19 vs. 25.3 +/- 1.54, means +/- SE, respectively), as was minute ventilation at a single work load (50 W) (32.4 +/- 2.3 vs. 25.7 +/- 1.54 l/min, means +/- SE, respectively). This increased ventilation during exercise in the elderly was not produced by arterial O2 desaturation, and increased anaerobiasis did not play a role. Instead, the increased ventilation during exercise seems to compensate for increased inefficiency of gas exchange such that exercise remains essentially isocapnic. In conclusion, in the elderly the ventilatory response to hypercapnia is less than in young subjects, whereas the ventilatory response to exercise is greater.

Effect of dopamine on transient ventilatory response to exercise

1986 ◽  
Vol 61 (6) ◽  
pp. 2102-2107 ◽  
Author(s):  
C. L. Boetger ◽  
D. S. Ward
Keyword(s):  
Steady State ◽  
Ventilatory Response ◽  
Work Load ◽  
Exponential Model ◽  
Bicycle Ergometer ◽  
Co2 Production ◽  
Load Testing ◽  
State Response ◽  
Exercise Hyperpnea ◽  
Response To Exercise

The effect of exogenous dopamine on the development of exercise hyperpnea was studied. Using a bicycle ergometer, five subjects performed repetitive square-wave work-load testing from unloaded pedaling to 80% of each subject's estimated anaerobic threshold. The breath-by-breath ventilation (VE), CO2 production (VCO2), and O2 consumption (VO2) responses were analyzed by curve fitting a first-order exponential model. Comparisons were made between control experiments and experiments with a 3-micrograms X kg-1 X min-1 intravenous infusion of dopamine. Steady-state VE, VCO2 and VO2 were unchanged by the dopamine infusion, both during unloaded pedaling and at the heavier work load. The time constants for the increase in VE (tau VE) and VCO2 (tau CO2) were significantly (P less than 0.05) slowed (tau VE = 56.5 +/- 16.4 s for control, and tau VE = 76.4 +/- 26.6 s for dopamine; tau CO2 = 51.5 +/- 10.6 s for control, and tau CO2 = 64.8 +/- 17.4 s for dopamine) (mean +/- SD), but the time constant for VO2 (tau O2) was not significantly affected (tau O2 = 27.5 +/- 11.7 s for control, and tau O2 = 31.0 +/- 10.1 s for dopamine). We conclude that ablation of carotid body chemosensitivity with dopamine slows the transient ventilatory response to exercise while leaving the steady-state response unaffected.

Gain of the ventilatory exercise stimulus: definition and meaning

1988 ◽  
Vol 65 (5) ◽  
pp. 2011-2017 ◽  
Author(s):  
F. M. Bennett ◽  
W. E. Fordyce
Keyword(s):  
Ventilatory Response ◽  
Fundamental Property ◽  
Co2 Production ◽  
Nonlinear Properties ◽  
Exchange Processes ◽  
The Mean ◽  
Response To Exercise ◽  
The Relationship ◽  
Exercise Stimulus ◽  
Arterial Po2

The ratio G = delta VE/delta VCO2 where delta VA is change in ventilation and delta VCO2 is change in CO2 production, is often used to quantitate the ventilatory response to exercise and is the overall system gain (G). However, the actual variable of interest often is the gain for the exercise stimulus (GEX). Exercise stimulus refers to a stimulus or group of stimuli other than the mean levels of arterial PO2 (PaCO2), PCO2 (PaCO2), and pH (pHa) that act to increase ventilation during exercise. GEX will be equal to G only if the response to exercise is precisely isocapnic, normoxic, and without metabolic acidosis. A mathematical model was used to examine the relationship between G and GEX when 1) the response to exercise is not strictly isocapnic and 2) when the resting PaCO2 is shifted away from its normal value. It was found that 1) when the exercise response was not strictly isocapnic, G was a poor estimate of GEX and 2) when resting PaCO2 was changed while GEX wa assumed to remain constant, G was a function of the resting PaCO2. However, this dependence of G on resting PaCO2 is a system property that was caused by the nonlinear properties of the gas exchange processes and was not a fundamental property of the controller. It is concluded that G may not always be a good estimate of GEX and may lead to incorrect conclusions concerning the nature of the exercise stimulus.

Ventilation and breathlessness on maximal exercise in patients with interstitial lung disease after local anaesthetic aerosol inhalation

1988 ◽  
Vol 74 (3) ◽  
pp. 275-281 ◽  
Author(s):  
A. J. Winning ◽  
R. D. Hamilton ◽  
A. Guz
Keyword(s):  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Maximal Exercise ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Statistical Significance ◽  
Co2 Production ◽  
Arterial Oxygen ◽  
Cough Reflex ◽  
Response To Exercise

1. The ventilatory response to maximal incremental exercise and the accompanying sensation of breathlessness were studied after the inhalation of 0.9% sodium chloride (saline) and 5% bupivacaine aerosols in six patients with interstitial lung disease. 2. The adequacy of airway anaesthesia induced by bupivacaine aerosol was confirmed by the absence of the cough reflex to 5% citric acid aerosol on completion of exercise. 3. All subjects first performed a trial exercise test to familiarize them with the procedure and to assess the degree of arterial oxygen desaturation on exercise. In subsequent tests, supplementary oxygen was given to maintain the saturation at 95% or above. 4. Airway anaesthesia had no effect on the ability to perform exercise as assessed by maximum workload, CO2 production or heart rate. No significant changes were seen on the pattern of breathing, minute ventilation or endtidal Pco2 on exercise. There was, however, a small but statistically significant increase in ventilation related to CO2 production (VE/Vco2) at the end of exercise. 5. There was a tendency for breathlessness to be increased by airway anaesthesia but this did not reach statistical significance. 6. These results provide no evidence that vagal afferent activity is responsible for the abnormal ventilatory response to exercise in patients with interstitial lung disease. The perception of breathlessness in these patients was not diminished by anaesthesia of the airway.

Respiratory muscle activity during sleep-induced periodic breathing in the elderly

1994 ◽  
Vol 77 (5) ◽  
pp. 2285-2290 ◽  
Author(s):  
D. W. Hudgel ◽  
H. B. Hamilton
Keyword(s):  
Tidal Volume ◽  
Airway Resistance ◽  
Minute Ventilation ◽  
Upper Airway ◽  
Periodic Breathing ◽  
Nrem Sleep ◽  
The Elderly ◽  
Elderly Subjects ◽  
Upper Airway Resistance ◽  
The Relationship

During spontaneous sleep-induced periodic breathing in elderly subjects, we have found that tidal volume oscillations are related to reciprocal oscillations in upper airway resistance. The purpose of this study was to address the mechanism of the relationship between oscillations in tidal volume and upper airway resistance in elderly subjects with sleep-induced periodic breathing. We hypothesized that the spontaneous periodic breathing observed in non-rapid-eye-movement (NREM) sleep in elderly subjects would be closely related to fluctuations in upper airway resistance and not to changes in central motor drive to ventilatory pump muscles. Therefore, in eight healthy elderly subjects, we measured costal margin chest wall peak moving time average electrical inspiratory activity (CW EMG), ventilation variables, and upper airway resistance during sleep. Five of eight subjects had significant sine wave oscillations in upper airway resistance and tidal volume. For these five subjects, there was a reciprocal exponential relationship between peak upper airway inspiratory resistance and tidal volume or minute ventilation [r = -0.60 +/- 0.20 (SD) (P < 0.05) and -0.55 +/- 0.26 (P < 0.05), respectively], such that as resistance increased, ventilation decreased. The relationship between CW EMG and tidal volume or minute ventilation was quite low (r = 0.12 +/- 0.32 and -0.07 +/- 0.27, respectively). This study demonstrated that oscillations in ventilation during NREM sleep in elderly subjects were significantly related to fluctuations in upper airway resistance but were not related to changes in chest wall muscle electrical activity. Therefore, changes in upper airway caliber likely contribute to oscillations in ventilation seen during sleep-induced periodic breathing in the elderly.

Response to hypercapnia and exercise hyperpnea in graded anesthesia

1984 ◽  
Vol 57 (6) ◽  
pp. 1796-1802 ◽  
Author(s):  
T. Chonan ◽  
Y. Kikuchi ◽  
W. Hida ◽  
C. Shindoh ◽  
H. Inoue ◽  
...  
Keyword(s):  
Steady State ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Exercise Hyperpnea ◽  
Sciatic Nerves ◽  
End Tidal ◽  
Response To Exercise ◽  
The Relationship ◽  
End Tidal Co2 ◽  
Rebreathing Method

We examined the relationship between response to hypercapnia and ventilatory response to exercise under graded anesthesia in eight dogs. The response to hypercapnia was measured by the CO2 rebreathing method under three grades of chloralose-urethan anesthesia. The degrees of response to hypercapnia (delta VE/delta PETCO2, 1 X min-1 X Torr-1) in light (L), moderate (M), and deep (D) anesthesia were 0.40 +/- 0.05 (mean +/- SE), 0.24 +/- 0.03, and 0.10 +/- 0.02, respectively, and were significantly different from each other. Under each grade of anesthesia, exercise was performed by electrically stimulating the bilateral femoral and sciatic nerves for 4 min. The time to reach 63% of full response of the increase in ventilation (tauVE) after beginning of exercise was 28.3 +/- 1.5, 38.1 +/- 5.2, and 56.0 +/- 6.1 s in L, M, and D, respectively. During steady-state exercise, minute ventilation (VE) in L, M, and D significantly increased to 6.17 +/- 0.39, 5.14 +/- 0.30, and 3.41 +/- 0.16 1 X min-1, from resting values of 3.93 +/- 0.34, 2.97 +/- 0.17, and 1.69 +/- 0.14 1 X min-1, respectively, while end-tidal CO2 tension (PETCO2) in L decreased significantly to 34.8 +/- 0.9 from 35.7 +/- 0.9, did not change in M (38.9 +/- 1.1 from 38.9 +/- 0.8), and increased significantly in D to 47.3 +/- 1.9 from 45.1 +/- 1.7 Torr.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The Road More Travelled: The Differential Effects of Spatial Experience in Young and Elderly Participants

2021 ◽  
Vol 18 (2) ◽  
pp. 709
Author(s):  
Antonella Lopez ◽  
Alessandro Germani ◽  
Luigi Tinella ◽  
Alessandro Oronzo Caffò ◽  
Albert Postma ◽  
...  
Keyword(s):  
Mental Representations ◽  
Spatial Relations ◽  
The Elderly ◽  
The Road ◽  
Socio Demographic Factors ◽  
Effects Of Aging ◽  
Coordinate Spatial Relations ◽  
Categorical Spatial Relations ◽  
The Relationship

Our spatial mental representations allow us to give refined descriptions of the environment in terms of the relative locations and distances between objects and landmarks. In this study, we investigated the effects of familiarity with the everyday environment, in terms of frequency of exploration and mode of transportation, on categorical and coordinate spatial relations, on young and elderly participants, controlling for socio-demographic factors. Participants were tested with a general anamnesis, a neuropsychological assessment, measures of explorations and the Landmark Positioning on a Map task. The results showed: (a) a modest difference in performance with categorical spatial relations; (b) a larger difference in coordinate spatial relations; (c) a significant moderating effect of age on the relationship between familiarity and spatial relations, with a stronger relation among the elderly than the young. Ceteris paribus, the role of direct experience with exploring their hometown on spatial mental representations appeared to be more important in the elderly than in the young. This advantage appears to make the elderly wiser and likely protects them from the detrimental effects of aging on spatial mental representations.

Sexual influence on the control of breathing

1983 ◽  
Vol 54 (4) ◽  
pp. 874-879 ◽  
Author(s):  
D. P. White ◽  
N. J. Douglas ◽  
C. K. Pickett ◽  
J. V. Weil ◽  
C. W. Zwillich
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Premenopausal Women ◽  
Co2 Production ◽  
Menstrual Phase ◽  
Co2 Partial Pressure ◽  
Ventilatory Responses ◽  
Chemical Stimuli ◽  
Low Levels ◽  
Normal Women

Previous investigation has demonstrated that progesterone, a hormone found in premenopausal women, is a ventilatory stimulant. However, fragmentary data suggest that normal women may have lower ventilatory responses to chemical stimuli than men, in whom progesterone is found at low levels. As male-female differences have not been carefully studied, we undertook a systematic comparison of resting ventilation and ventilatory responses to chemical stimuli in men and women. Resting ventilation was found to correlate closely with CO2 production in all subjects (r = 0.71, P less than 0.001), but women tended to have a greater minute ventilation per milliliter of CO2 produced (P less than 0.05) and consequently a lower CO2 partial pressure (PCO2) (men 35.1 +/- 0.5 Torr, women 33.2 +/- 0.5 Torr; P less than 0.02). Women were also found to have lower tidal volumes, even when corrected from body surface area (BSA), and greater respiratory frequency than comparable males. The hypoxic ventilatory response (HVR) quantitated by the shape parameter A was significantly greater in men [167 +/- 22 (SE)] than in women (109 +/- 13; P less than 0.05). In men this hypoxic response was found to correlate closely with O2 consumption (r = 0.75, P less than 0.001) but with no measure of size or metabolic rate in women. The hypercapnic ventilatory response, expressed as the slope of ventilation vs. PCO2, was also greater in men (2.30 +/- 0.23) than in women (1.58 +/- 0.19, P less than 0.05). Finally women tended to have higher ventilatory responses in the luteal than in the follicular menstrual phase, but this was significant only for HVR (P less than 0.05). Women, with relatively higher resting ventilation, have lower responses to hypoxia and hypercapnia.

scholarly journals Arterial-cardiac baroreflex function: insights from repeated squat-stand maneuvers

2009 ◽  
Vol 297 (1) ◽  
pp. R116-R123 ◽  
Author(s):  
Rong Zhang ◽  
Jurgen A. H. R. Claassen ◽  
Shigeki Shibata ◽  
Sinem Kilic ◽  
Kristin Martin-Cook ◽  
...  
Keyword(s):  
Transfer Function ◽  
Arterial Pressure ◽  
Body Position ◽  
The Elderly ◽  
Elderly Subjects ◽  
Pulley System ◽  
New Approach ◽  
Baroreflex Function ◽  
Effects Of Aging ◽  
Transfer Function Gain

To assess baroreflex function under closed-loop conditions, a new approach was used to generate large and physiological perturbations in arterial pressure. Blood pressure (BP) and R-R interval were recorded continuously in 20 healthy young (33 ± 8 yr) and eight elderly subjects (66 ± 6 yr). Repeated squat-stand maneuvers at the frequencies of 0.05 and 0.1 Hz were performed to produce periodic oscillations in BP to provoke the baroreflex. To assess the effects of the muscle reflex and/or central command on the baroreflex, passive squat-stand maneuvers were conducted using a pulley system to assist changes in body position. Transfer function between changes in BP and R-R interval was estimated to assess the arterial-cardiac baroreflex. Relative to resting conditions, large and coherent oscillations in BP and R-R interval were produced during both active and passive squat-stand maneuvers. However, changes in BP were smaller during passive than during active maneuvers. Changes in R-R interval were reduced commensurately. Therefore, transfer function gain did not change between the two maneuvers. Compared with the young, transfer function gain was reduced and the phase became more negative in the elderly, demonstrating the well-known effects of aging on reducing baroreflex sensitivity. Collectively, these findings suggest that the changes in R-R interval elicited by BP perturbations during squat-stand maneuvers are mediated primarily by a baroreflex mechanism. Furthermore, baroreflex function can be assessed using the transfer function method during large perturbations in arterial pressure.

Antidepressant and antipsychotic drug prescribing in Lombardy

2006 ◽  
Vol 15 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Mauro Percudani ◽  
Corrado Barbui ◽  
Ida Fortino ◽  
Michele Tansella ◽  
Lorenzo Petrovich
Keyword(s):  
Antipsychotic Drug ◽  
The Elderly ◽  
Elderly Subjects ◽  
Drug Prescribing ◽  
Very Old ◽  
Cerebrovascular Accidents ◽  
Pragmatic Clinical Trials ◽  
Increased Risk ◽  
Catchment Areas ◽  
The Relationship

SUMMARYBackground – The patterns of antidepressant and antipsychotìc drag prescribing have rarely been studied in large and geographically defined catchment areas. In the present study we examined the prevalence and distribution of antidepressant and antipsychotic prescribing in Lombardy, a northern Italy region of nine million inhabitants. Methods – This study used the Regional Administrative Database of Lombardy. This database includes all prescriptions reimbursed by the National Health System in the population living in this region. All antidepressant and antipsychotic prescriptions dispensed from the 1st January to the 31st December 2001 were extracted and prevalence data calculated by dividing antidepressant and antipsychotic users by the total number of male and female residents in each age group. In addition, from the Regional database of hospital admissions we extracted all patients aged 65 or above with cerebrovascular-related outcomes for the year 2002. The two databases were linked anonymously with the aim of investigating the relationship between exposure to psychotropics and occurrence of cerebrovascular accidents in the elderly. Results – During the study period 404, 238 individuals were dispensed antidepressants, yielding a prevalence of use of 2.85 (95% CI 2.84, 2.87) per 100 males and 5.92 (95% CI 5.90, 5.94) per 100 females. The prevalence of use progressively rose with age in both sexes, with the highest rates in old and very old individuals. The majority of individuals received a pharmacological treatment with selective-serotonin reuptake inhibitors only, slightly more than 12% received a treatment with tricyclic antidepressants. A total of 86, 187 subjects were dispensed antipsychotic agents, yielding a prevalence of use of 0.87 (95% CI 0.86, 0.88) per 100 males and 1.01 (95% CI 1.00, 1.02) per 100 females. The prevalence of use progressively rose with age in both sexes, with the highest rates in old and very old subjects. Concerning the relationship between exposure to second-generation antipsychotics (SGAs) and occurrence of cerebrovascular (CBV) accidents, the analysis showed a significantly increased risk of CBV events in elderly subjects exposed to SGAs in comparison with those exposed to first-generation antipsychotics (FGAs) (3, 31%, 95% CI 2, 95–3, 69 vs. 2, 37%, 95% CI 2, 19–2, 57). Finally the analysis indicated no differences in the proportion of cerebrovascular events in elderly subjects exposed to TCAs and SSRIs. Conclusions – The very high rates of antidepressant and antipsychotic drug prescribing detected in late life suggest the need of characterising these individuals in terms of medical and psychiatric characteristics, needs and quality of life. It also suggests the need for pragmatic clinical trials, carried out in the general practice, with the aim of assessing whether antidepressants are effective in these conditions. The data provide preliminary epidemiological evidence that exposure to SGAs, in comparison with exposure to FGAs, significantly increased the risk of cerebrovascular accidents in the elderly.Declaration of Interest: none.

scholarly journals Ventilatory response to exercise in subjects breathing CO2 or HeO2

1997 ◽  
Vol 82 (3) ◽  
pp. 746-754 ◽  
Author(s):  
T. G. Babb
Keyword(s):  
Maximal Exercise ◽  
Respiratory Mechanics ◽  
Ventilatory Threshold ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Normal Lung ◽  
Normal Lung Function ◽  
Older Subjects ◽  
Breathing Room ◽  
Response To Exercise

Babb, T. G. Ventilatory response to exercise in subjects breathing CO2 or HeO2. J. Appl. Physiol. 82(3): 746–754, 1997.—To investigate the effects of mechanical ventilatory limitation on the ventilatory response to exercise, eight older subjects with normal lung function were studied. Each subject performed graded cycle ergometry to exhaustion once while breathing room air; once while breathing 3% CO2-21% O2-balance N2; and once while breathing HeO2 (79% He and 21% O2). Minute ventilation (V˙e) and respiratory mechanics were measured continuously during each 1-min increment in work rate (10 or 20 W). Data were analyzed at rest, at ventilatory threshold (VTh), and at maximal exercise. When the subjects were breathing 3% CO2, there was an increase ( P < 0.001) inV˙e at rest and at VTh but not during maximal exercise. When the subjects were breathing HeO2,V˙e was increased ( P < 0.05) only during maximal exercise (24 ± 11%). The ventilatory response to exercise below VTh was greater only when the subjects were breathing 3% CO2( P < 0.05). Above VTh, the ventilatory response when the subjects were breathing HeO2 was greater than when breathing 3% CO2( P < 0.01). Flow limitation, as percent of tidal volume, during maximal exercise was greater ( P < 0.01) when the subjects were breathing CO2 (22 ± 12%) than when breathing room air (12 ± 9%) or when breathing HeO2 (10 ± 7%) ( n = 7). End-expiratory lung volume during maximal exercise was lower when the subjects were breathing HeO2 than when breathing room air or when breathing CO2( P < 0.01). These data indicate that older subjects have little reserve for accommodating an increase in ventilatory demand and suggest that mechanical ventilatory constraints influence both the magnitude of V˙eduring maximal exercise and the regulation ofV˙e and respiratory mechanics during heavy-to-maximal exercise.

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