Cardiopulmonary and metabolic physiology during hemodialysis and inter-/intra-dialytic exercise

Background: Hemodialysis is associated with numerous symptoms and side effects which, in part, maybe due to sub-clinical hypoxia. However, acute cardio-pulmonary and metabolic physiology during hemodialysis is not well defined. Intra-dialytic and inter-dialytic exercise appear to be beneficial and may alleviate these side effects. To better understand these potential benefits, the acute physiological response to exercise should be evaluated. The aim of this study was to compare and characterise the acute physiological response during hemodialysis, intra-dialytic and inter-dialytic exercise. Methods: Cardiopulmonary physiology was evaluated during three conditions; 1) hemodialysis without exercise (HD), 2) intra-dialytic exercise (IDEx), and 3) inter-dialytic exercise (Ex). Exercise consisted of 30 minutes constant load cycle ergometry at 90% VO2AT. Central hemodynamics (via non-invasive bio-reactance) and ventilatory gas exchange were recorded during each experimental condition. Results: Twenty participants (59 ± 12 yrs, 16/20 male) completed the protocol. Cardiac output (Δ = -0.7 L/min), O2 uptake (Δ = -1.4 ml.kg-1.min-1) and arterial-venous O2 difference (Δ = -2.0 ml/O2/100ml) decreased significantly during HD. Respiratory exchange ratio exceeded 1.0 throughout HD and IDEx. Minute ventilation was lower (p = 0.001) during IDEx (16.5 ± 1.1 L/min) compared to Ex (19.8 ± 1.0 L/min). Arterial-venous O2 difference was partially restored further to IDEx (4.6 ± 1.9 ml/O2/100ml) compared to HD (3.5 ± 1.2 ml/O2/100ml). Conclusion: Hemodialysis altered cardiopulmonary and metabolic physiology, suggestive of hypoxia. This dysregulated physiology contributed to a greater physiological demand during intra-dialytic compared to inter-dialytic exercise. Despite this, intra-dialytic exercise partly normalised physiology during treatment.

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Coupling of ventilation to pulmonary gas exchange during nonsteady-state work in men

Journal of Applied Physiology ◽

10.1152/jappl.1983.54.2.587 ◽

1983 ◽

Vol 54 (2) ◽

pp. 587-593 ◽

Cited By ~ 32

Author(s):

D. H. Wasserman ◽

B. J. Whipp

Keyword(s):

Gas Exchange ◽

Minute Ventilation ◽

Normal Subjects ◽

Load Cycle ◽

Constant Load ◽

Response Dynamics ◽

Co2 Output ◽

Exercise Ventilation ◽

Nonsteady State ◽

End Tidal

During steady-state exercise, ventilation increases in proportion to CO2 output (VCO2), regulating arterial PCO2. To characterize the dynamics of ventilatory coupling to VCO2 and O2 uptake (VO2) in the nonsteady-state phase, seven normal subjects performed constant-load cycle ergometry to a series of subanaerobic threshold work rates. Each bout consisted of eight 6-min periods of alternating loaded and unloaded cycling. Ventilation and gas exchange variables were computed breath by breath, with the time-averaged response dynamics being established off-line. Ventilation increased as a linear function of VCO2 in all cases, the relationship being identical in the steady- and the nonsteady-state phases. Ventilation, however, bore a curvilinear relation to VO2, the kinetics of the latter being more rapid. Owing to the kinetic disparity between expired minute ventilation (VE) and VO2, there was an overshoot in the direction of change in VE/VO2 and end-tidal PO2 during the work-rate transition. In contrast, there was no overshoot in the direction of change in VE/VCO2 and end-tidal PCO2 throughout the nonsteady-state period. These data suggest that the exercise hyperpnea is coupled to metabolism in men via a signal proportional to VCO2 in both the nonsteady and steady states of moderate exercise.

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Chronic Asthma: An Update

Pediatrics in Review ◽

10.1542/pir.17.4.111 ◽

1996 ◽

Vol 17 (4) ◽

pp. 111-117

Author(s):

Kathi J. Kemper

Keyword(s):

Side Effects ◽

Alternative Therapies ◽

Herbal Remedies ◽

Chronic Asthma ◽

Case Scenario ◽

Mineral Supplements ◽

Current Medication ◽

Ma Huang ◽

Potential Benefits ◽

Routine Physical Examination

Case Scenario Having just changed insurance carriers, a mother brings her 13-year-old son to your office for a routine physical examination. He has no current complaints except for chronic asthma. His past medical history is significant for several hospitalizations for asthma. His only current medication is an albuterol inhaler that he uses two to three times daily. Further questioning about home remedies reveals that in an effort to cut down on his chronic use of medication, he recently started taking the herbal remedies Ma huang and Dong quai as well as vitamin and mineral supplements. He wants to know how safe and effective these therapies are and if you have any other suggestions to help him with his symptoms and avoid another hospitalization. Because of its severity and complexity, asthma and its treatment are often frustrating for patients, families, and clinicians. Out of desperation, many patients and families turn to alternative therapies, such as nutrition, herbs, and Chinese medicine. With the growing interest in and use of alternative therapies, practitioners would do well to become familiar with them, their side effects, and potential benefits. Traditional medical management also has changed; modern therapy emphasizes anti-inflammatory rather than bronchodilator medication. This review focuses on modern management of chronic asthma symptoms and highlights recent evidence about the effectiveness and side effects of alternative treatments.

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Group music lessons for children aged 1–3 improve accompanying parents’ moods

Psychology of Music ◽

10.1177/0305735618803791 ◽

2018 ◽

Vol 48 (3) ◽

pp. 410-420 ◽

Cited By ~ 1

Author(s):

Satoshi Kawase ◽

Jun’ichi Ogawa

Keyword(s):

Side Effects ◽

Questionnaire Survey ◽

State Anxiety ◽

Positive Mood ◽

Music Lessons ◽

Before And After ◽

Potential Benefits ◽

Peripheral Participation ◽

Musical Activities

This study investigated the improvement in parents’ moods when attending group music lessons targeting their children aged 1–3 years. A questionnaire survey of parents’ moods was conducted under three conditions: immediately before and after the lesson, and on a non-lesson day. Results suggested that group music lessons for children enhanced parents’ positive mood and reduced anxiety. Thus, even peripheral participation in children’s group music lessons can be beneficial for parents. In addition, such mood improvements were more significant in the parents whose everyday state anxiety was high than in parents whose state anxiety was low. Since only few parents answered that their motivation in taking the lesson was to benefit themselves, the results of the study suggest side effects of children’s group music lessons for parents. These imply the potential benefits of musical activities for non-primary targeted participants who are not clearly aware of the positive musical effects for themselves.

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Ventilatory response to exercise in subjects breathing CO2 or HeO2

Journal of Applied Physiology ◽

10.1152/jappl.1997.82.3.746 ◽

1997 ◽

Vol 82 (3) ◽

pp. 746-754 ◽

Cited By ~ 65

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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Symptom And Physiological Response To Exercise Following Concussion

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000675284.01951.be ◽

2020 ◽

Vol 52 (7S) ◽

pp. 168-168

Author(s):

David R. Howell ◽

Danielle Hunt ◽

Stacey E. Aaron ◽

J Andrew Taylor ◽

William P. Meehan ◽

...

Keyword(s):

Physiological Response ◽

Response To Exercise

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A constant-load ergometer for measuring peak power output and fatigue

Journal of Applied Physiology ◽

10.1152/jappl.1988.65.5.2343 ◽

1988 ◽

Vol 65 (5) ◽

pp. 2343-2348 ◽

Cited By ~ 18

Author(s):

J. H. Williams ◽

W. S. Barnes ◽

J. F. Signorile

Keyword(s):

Power Output ◽

Peak Power ◽

Intraclass Correlation ◽

Average Power ◽

Load Cycle ◽

Constant Load ◽

Load Cell ◽

Peak Power Output ◽

Maximal Power Output ◽

Power Curves

A constant-load cycle ergometer was constructed that allows maximal power output to be measured for each one-half pedal revolution during brief, high-intensity exercise. To determine frictional force, an electronic load cell was attached to the resistance strap and the ergometer frame. Dead weights were attached to the strap's free end. Flywheel velocity was recorded by means of a magnetic switch and two magnets placed on the pedal sprocket. Pedaling resulted in magnetically activated switch closures, which produced two electronic pulses per pedal revolution. Pulses and load cell output were recorded (512 Hz), digitized, and stored on disk via microcomputer. Power output was later computed for each pair of adjacent pulses, representing average power per one-half pedal revolution. Power curves generated for each subject were analyzed for peak power output (the highest one-half pedal revolution average), time to peak power, power fatigue rate and index, average power, and total work. Thirty-eight males performed two 15-s tests separated by 15 min (n = 16) or 48 h (n = 22). Peak power output ranged from 846.0 to 1,289.1 W. Intraclass correlation analysis revealed high test-retest reliability for all parameters recorded on the same or different days (R = 0.91-0.97). No significant differences (P greater than 0.05) were noted between parameter means of the first and second tests. These results indicate that the ergometer described provides a means for conveniently and reliably assessing short-term power output and fatigue.

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Cycling Time Trial Performance May Be Impaired by Whey Protein and L-Alanine Intake During Prolonged Exercise

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.2013-0173 ◽

2014 ◽

Vol 24 (5) ◽

pp. 507-515 ◽

Cited By ~ 7

Author(s):

Adam B. Schroer ◽

Michael J. Saunders ◽

Daniel A. Baur ◽

Christopher J. Womack ◽

Nicholas D. Luden

Keyword(s):

Time Trial ◽

Endurance Performance ◽

Constant Load ◽

Protein Amino Acid ◽

Cycling Time Trial ◽

Glucose Levels ◽

Load Cycling ◽

Additional Protein ◽

Response To Exercise ◽

The Impact

Previous studies reported that adding protein (PRO) to carbohydrate (CHO) solutions enhances endurance performance. The ergogenic effect may be a function of additional protein/amino acid calories, but this has not been examined. In addition, although supplemental L-alanine (ALA) is readily oxidized during exercise, the subsequent impact on metabolism and prolonged endurance performance is unknown. The purpose of this investigation was to independently gauge the impact of whey PRO hydrolysate and ALA supplementation on performance and various physiological parameters. Eight cyclists (age: 22.3 ± 5.6 yr, weight: 70.0 ± 8.0 kg, VO2max: 59.4 ± 4.9 ml·kg−1·min−1) performed 120 min of constant-load cycling (55% of peak power) followed by a 30-km time trial (TT) under placebo (PLA), PRO, and ALA conditions. Magnitude-based qualitative inferences were applied to evaluate treatment differences and data are presented as percent difference between treatments ± 90% confidence limit. Both ALA (–2.1 ± 2.7%) and PRO intake (–2.1 ± 2.2%) possibly harmed performance compared with PLA. Of interest, heart rate was possibly lower with ALA than PLA at 20– (–2.7 ± 3.4%) and 120-min (–1.7 ± 2.9%) of constant-load cycling and the serum interleukin-6 (IL-6) response to 120 min of cycling was likely attenuated with PRO compared with PLA (PLA, 6.6 ± 3.7 fold vs. PRO, 2.9 ± 1.8 fold). In addition, blood glucose levels were lower with PRO than PLA at 20– (–8.8 ± 2.3%; very likely) and 120-min (–4.9 ± 4.6%; likely) of constant-load cycling. Although ALA intake appears to lower HR and PRO ingestion dampens the IL-6 response to exercise, the ingestion of PRO (without CHO) or ALA does not enhance, and may actually impair, performance following prolonged cycling.

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The olfactory system in Alzheimer’s disease: Pathology, pathophysiology and pathway for therapy

Translational Neuroscience ◽

10.2478/s13380-013-0108-3 ◽

2013 ◽

Vol 4 (1) ◽

Cited By ~ 11

Author(s):

Tibor Kovács

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Nerve Growth Factor ◽

Growth Factor ◽

Side Effects ◽

Olfactory System ◽

Therapeutic Agents ◽

Non Invasive ◽

Degenerative Disorders ◽

Invasive Method

AbstractOlfaction is frequently mentioned as a “neglected sense”, although the olfactory system has several interesting and unique anatomical and physiological features. Olfactory involvement is present in several degenerative disorders, especially in Alzheimer’s disease (AD). The peripheral and central parts of the olfactory system are damaged even in the early stages of AD, manifesting in profound olfactory deficits. Besides the early pathology, the olfactory system may be involved in the pathogenesis of AD by providing a route of entry for pathological agents still unknown. In contrast to this olfactory vector hypothesis, the olfactory system can be used to deliver therapeutic agents in AD, such as nerve growth factor and insulin, by decreasing the side-effects of the therapy or providing a non-invasive method of delivery.

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Pulmonary gas exchange response to exercise- and mannitol-induced bronchoconstriction in mild asthma

Journal of Applied Physiology ◽

10.1152/japplphysiol.00108.2008 ◽

2008 ◽

Vol 105 (5) ◽

pp. 1477-1485 ◽

Cited By ~ 27

Author(s):

Phillip A. Muñoz ◽

Federico P. Gómez ◽

Hernán A. Manrique ◽

Josep Roca ◽

Joan A. Barberà ◽

...

Keyword(s):

Blood Flow ◽

Gas Exchange ◽

Minute Ventilation ◽

Forced Expiratory Volume ◽

Pulmonary Gas Exchange ◽

Slow Recovery ◽

Airway Narrowing ◽

Asthmatic Patients ◽

Response To Exercise ◽

Blood Flow Redistribution

Both exercise (EIB) and mannitol challenges were performed in asthmatic patients to assess and compare their pulmonary gas exchange responses for an equivalent degree of bronchoconstriction. In 11 subjects with EIB [27 ± 4 (SD) yr; forced expiratory volume in 1 s (FEV1), 86 ± 8% predicted], ventilation-perfusion (V̇a/Q̇) distributions (using multiple inert gas elimination technique) were measured 5, 15, and 45 min after cycling exercise (FEV1 fall, 35 ± 12%) and after mannitol (33 ± 10%), 1 wk apart. Five minutes after EIB, minute ventilation (V̇e; by 123 ± 60%), cardiac output (Q̇t, by 48 ± 29%), and oxygen uptake (V̇o2; by 54 ± 25%) increased, whereas arterial Po2 (PaO2; by 14 ± 11 Torr) decreased due to moderate V̇a/Q̇ imbalance, assessed by increases in dispersions of pulmonary blood flow (log SDQ̇; by 0.53 ± 0.16) and alveolar ventilation (log SDV̇; by 0.28 ± 0.15) (dimensionless) ( P < 0.01 each). In contrast, for an equivalent degree of bronchoconstriction and minor increases in V̇e, Q̇t, and V̇o2, mannitol decreased PaO2 more intensely (by 24 ± 9 Torr) despite fewer disturbances in log SDQ̇ (by 0.27 ± 0.12). Notwithstanding, mannitol-induced increase in log SDV̇ at 5 min (by 0.35 ± 0.15) was similar to that observed during EIB, as was the slow recovery in log SDV̇ and high V̇a/Q̇ ratio areas, at variance with the faster recovery of log SDQ̇ and low V̇a/Q̇ ratio areas. In asthmatic individuals, EIB provokes more V̇a/Q̇ imbalance but less hypoxemia than mannitol, primarily due to postexercise increases in V̇e and Q̇t benefiting PaO2. V̇a/Q̇ inequalities during both challenges most likely reflect uneven airway narrowing and blood flow redistribution generating distinctive V̇a/Q̇ patterns, including the development of areas with low and high V̇a/Q̇ ratios.

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