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1.
Nat Commun ; 14(1): 6311, 2023 10 09.
Article in English | MEDLINE | ID: mdl-37813884

ABSTRACT

Astronauts in microgravity experience multi-system deconditioning, impacting their inflight efficiency and inducing dysfunctions upon return to Earth gravity. To fill the sex gap of knowledge in the health impact of spaceflights, we simulate microgravity with a 5-day dry immersion in 18 healthy women (ClinicalTrials.gov Identifier: NCT05043974). Here we show that dry immersion rapidly induces a sedentarily-like metabolism shift mimicking the beginning of a metabolic syndrome with a drop in glucose tolerance, an increase in the atherogenic index of plasma, and an impaired lipid profile. Bone remodeling markers suggest a decreased bone formation coupled with an increased bone resorption. Fluid shifts and muscular unloading participate to a marked cardiovascular and sensorimotor deconditioning with decreased orthostatic tolerance, aerobic capacity, and postural balance. Collected datasets provide a comprehensive multi-systemic assessment of dry immersion effects in women and pave the way for future sex-based evaluations of countermeasures.


Subject(s)
Space Flight , Weightlessness , Humans , Female , Cardiovascular Deconditioning/physiology , Immersion , Weightlessness/adverse effects , Weightlessness Simulation
2.
Neurorehabil Neural Repair ; 35(6): 471-485, 2021 06.
Article in English | MEDLINE | ID: mdl-33825581

ABSTRACT

Evidence supports early rehabilitation after stroke to limit disability. However, stroke survivors are typically sedentary and experience significant cardiovascular and muscular deconditioning. Despite growing consensus that preclinical and clinical stroke recovery research should be aligned, there have been few attempts to incorporate cardiovascular and skeletal muscle deconditioning into animal models of stroke. Here, we demonstrate in rats that a hindlimb sensorimotor cortex stroke results in both cardiovascular and skeletal muscle deconditioning and impairments in gait akin to those observed in humans. To reduce poststroke behavioral, cardiovascular, and skeletal muscle perturbations, we then used a combinatorial intervention consisting of aerobic and resistance exercise in conjunction with administration of resveratrol (RESV), a drug with exercise mimetic properties. A combination of aerobic and resistance exercise mitigated decreases in cardiovascular fitness and attenuated skeletal muscle abnormalities. RESV, beginning 24 hours poststroke, reduced acute hindlimb impairments, improved recovery in hindlimb function, increased vascular density in the perilesional cortex, and attenuated skeletal muscle fiber changes. Early RESV treatment and aerobic and resistance exercise independently provided poststroke benefits, at a time when individuals are rapidly becoming deconditioned as a result of inactivity. Although no additive effects were observed in these experiments, this approach represents a promising strategy to reduce poststroke behavioral impairments and minimize deconditioning. As such, this treatment regime has potential for enabling patients to engage in more intensive rehabilitation at an earlier time following stroke when mechanisms of neuroplasticity are most prevalent.


Subject(s)
Antioxidants/pharmacology , Cardiovascular Deconditioning , Muscle, Skeletal , Physical Conditioning, Animal/physiology , Recovery of Function , Resistance Training , Resveratrol/pharmacology , Stroke Rehabilitation , Stroke/therapy , Animals , Antioxidants/administration & dosage , Behavior, Animal/drug effects , Behavior, Animal/physiology , Cardiovascular Deconditioning/drug effects , Cardiovascular Deconditioning/physiology , Combined Modality Therapy , Disease Models, Animal , Female , Hindlimb/drug effects , Hindlimb/physiopathology , Muscle, Skeletal/drug effects , Muscle, Skeletal/physiopathology , Rats , Rats, Sprague-Dawley , Recovery of Function/drug effects , Recovery of Function/physiology , Resveratrol/administration & dosage , Sensorimotor Cortex/drug effects , Sensorimotor Cortex/physiopathology , Stroke/drug therapy
3.
Rev Mal Respir ; 36(5): 591-599, 2019 May.
Article in French | MEDLINE | ID: mdl-31204232

ABSTRACT

INTRODUCTION: Chronic dyspnoea that remains unexplained after resting pulmonary function and cardiovascular testing is a common problem in clinical practice. The aim of this study was to determine the utility of cardiopulmonary exercise testing (CPET) in the diagnosis of unexplained dyspnoea. METHODS: This retrospective single-centre study included consecutive patients with dyspnoea who had normal resting cardiopulmonary examinations (including chest X-ray, electrocardiography, pulmonary function tests [PFTs], and cardiac ultrasound). CPET was performed using a cycle ergometer with analysis of blood gases. The results were interpreted as being most likely due to one of the six pathophysiological mechanisms shown below. Consensus required agreement between at least three of the authors. RESULTS: Of the 194 patients included (median age 53 years, sex-ratio (M:F) 0.83, mean body mass index 27.3±5.36kg/m2), 32% of the test profiles were compatible with deconditioning, 20% with inappropriate hyperventilation (without gas exchange abnormalities), 18% with disorders of gas exchange, 13% with sub-maximal CPET, 9% with cardiovascular anomalies, and 8% with normal CPET. Of the patients with gas exchange abnormalities, the most common causes were bronchiectasis (6), emphysema (6), recent pneumonia (2), and diffuse interstitial pneumonitis (2). Ten of the patients with cardiovascular abnormalities had chronotropic insufficiencies, 5 had excessive tension responses, and 3 had disorders of rhythm or repolarisation. CONCLUSIONS: CPET may greatly facilitate the diagnosis of unexplained dyspnoea. More than 50% of the dyspnoea cases examined here were due to deconditioning or hyperventilation syndrome and would benefit from a simple pulmonary rehabilitation program.


Subject(s)
Dyspnea/diagnosis , Exercise Test/methods , Adult , Cardiovascular Deconditioning/physiology , Dyspnea/etiology , Dyspnea/physiopathology , Exercise Tolerance/physiology , Female , Humans , Hyperventilation/diagnosis , Hyperventilation/etiology , Hyperventilation/physiopathology , Male , Middle Aged , Predictive Value of Tests , Respiratory Function Tests/methods , Retrospective Studies
4.
J Pak Med Assoc ; 68(12): 1755-1758, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30504941

ABSTRACT

OBJECTIVE: To determine the association between physical activity and cognition in age-related decline of college students and to find the correlation between physical activity with cardiovascular deconditioning. METHODS: The analytical cross-sectional study was conducted from January 1 to May 1, 2017, in different medical and engineering colleges of Rawalpindi and Islamabad in Pakistan.Data was collected through non-probability purposive sampling method. Demographic data was recorded and standardized assessment tools, including physical activity index and stroop colour word test for cognition, were used. Bivariate correlation analysis was used to determine association between different variables. RESULTS: Of the 702 subjects, 340(48.5%) were males and 362(51.7%) were females. The overall mean age was 21.84±1.73 years (range: 17-24 years), and mean body mass index was 22.12±3.6.Overall, 292 (41.8%) students were labelled as physically active and 410(58.8%) had sedentary lifestyle.Physical activity and cognition showed positive association (p=0.004) in students.Physically inactive participants showed cardiovascular and cognitive deconditioning with age (p = 0.68). CONCLUSIONS: Physical activity was found to be a key tool of cardiovascular health and cognition.It ameliorated overall health and brought better academic performance of students engaged in sports-related activities.


Subject(s)
Aging/physiology , Cardiovascular Deconditioning/physiology , Cognition/physiology , Exercise/physiology , Students/statistics & numerical data , Adolescent , Adult , Cross-Sectional Studies , Female , Humans , Male , Pakistan/epidemiology , Universities , Young Adult
5.
Aerosp Med Hum Perform ; 88(9): 827-833, 2017 Sep 01.
Article in English | MEDLINE | ID: mdl-28818141

ABSTRACT

BACKGROUND: Intermittent artificial gravity (AG) training over days and weeks has been shown to improve the human orthostatic tolerance limit (OTL) and improve cardiovascular regulation in response to orthostatic stress. Effects of a single AG exposure are currently unknown. METHODS: We tested cardiovascular responses to orthostatic stress in 16 hypovolemic subjects (9 men and 7 women), once following a single, short (∼90 min) bout of AG and once following a similar period of head-down bed rest (HDBR). Hypovolemia was produced by intravenous furosemide infusion (20 mg) and orthostatic stress was produced by combined 70° head-up tilt (HUT) and progressively increasing lower body negative pressure until symptoms of presyncope developed. To assess reflex-induced changes in cardiovascular regulation, heart rate and blood pressure variability were analyzed by spectral analysis and baroreflex activity was evaluated by transfer function analysis. RESULTS: Compared to HDBR, a short AG exposure increased men's low frequency (0.04-0.15 Hz) power of systolic blood pressure (SBPLF), but did not change women's SBPLF responses to orthostatic stress. In response to 70° HUT, compared to supine, low frequency phase delay (PhaseLF) between systolic blood pressure and RR intervals increased by ∼20% following HDBR, but did not change following AG, reflecting improved baroreflex activity at a milder level of orthostatic stress after AG. CONCLUSIONS: These results indicate that a short bout of AG increased both sympathetic and baroreflex responsiveness to orthostatic stress in hypovolemia-induced, cardiovascular-deconditioned men and women, which may contribute to the AG-induced improvement of OTL shown in our previous reports.Zhang Q, Evans JM, Stenger MB, Moore FB, Knapp CF. Autonomic cardiovascular responses to orthostatic stress after a short artificial gravity exposure. Aerosp Med Hum Perform. 2017; 88(9):827-833.


Subject(s)
Autonomic Nervous System/physiology , Cardiovascular Deconditioning/physiology , Gravity, Altered , Head-Down Tilt/physiology , Adult , Baroreflex/physiology , Bed Rest , Blood Pressure/physiology , Female , Heart Rate/physiology , Hemodynamics/physiology , Humans , Hypovolemia/physiopathology , Lower Body Negative Pressure , Male
6.
J Sports Med Phys Fitness ; 57(7-8): 1062-1068, 2017.
Article in English | MEDLINE | ID: mdl-28134506

ABSTRACT

BACKGROUND: Breast cancer is one of the leading causes of death worldwide. Heart rate variability (HRV) has attracted scientific community attention in different pathologies, becoming thus an ultimate importance tool in both clinical and research setting, being a good predictor of cardiac events and mortality risk and also used in physical exercise and sports in general. The aim of the present study was to evaluate 12 weeks of exercise training and six weeks of detraining in cardiorespiratory capacity, and autonomic modulation in breast cancer patients. METHODS: The sample was composed of 18 females (9 controls and 9 exercised), (aged 30-60 years). The HRV in the time and frequency domain was performed using an electrocardiogram before, after 12 weeks of the session of exercise training and after six weeks of detraining. Shapiro-Wilk and Mann-Whitney tests were made. RESULTS: No significant changes in time domain were found. In the frequency domain, 12 weeks of exercise training promote a decrease in LF (nu) and decrease in HF (nu) Index. The exercise training period promoted a decrease in LF/HF. The autonomic data returned to baseline levels after the detraining period. However, cardiorespiratory capacity remained increased after the detraining period. CONCLUSIONS: These data demonstrated that exercise training can be used to prevent autonomic dysfunction in breast cancer patients, but detraining promotes loss of all autonomic benefits.


Subject(s)
Autonomic Nervous System/physiology , Breast Neoplasms/physiopathology , Cancer Survivors , Carcinoma, Ductal, Breast/physiopathology , Cardiorespiratory Fitness/physiology , Exercise/physiology , Heart Rate/physiology , Adult , Breast Neoplasms/therapy , Cancer Survivors/statistics & numerical data , Carcinoma, Ductal, Breast/therapy , Cardiovascular Deconditioning/physiology , Case-Control Studies , Electrocardiography , Female , Humans , Middle Aged , Time Factors
7.
Chest ; 151(2): 431-440, 2017 02.
Article in English | MEDLINE | ID: mdl-27742182

ABSTRACT

BACKGROUND: Discriminating circulatory problems with reduced stroke volume (SV) from deconditioning, in which the muscles cannot consume oxygen normally, by gas exchange parameters is difficult. METHODS: We performed combined stress echocardiography (SE) and cardiopulmonary exercise tests (CPET) in 110 patients (20 with normal effort capacity, 54 with attenuated SV response, and 36 with deconditioning) to evaluate multiple hemodynamic parameters and oxygen content difference (A-V.o2 Diff) in four predefined activity levels to assess which of the gas measures may help in the discrimination. RESULTS: Reduced anaerobic threshold (AT), low unchanging peak oxygen pulse, periodic breathing, shallow Δ peak oxygen consumption (V.o2)/Δwork rate (WR) ratio, and high expired volume per unit time/carbon dioxide production (V.e/V.co2) slope were all associated with abnormal SV response (P < .05 for all). The best discriminator was V.e/V.co2 slope to V.o2 ratio (≥ 2.7; area under the curve [AUC], 0.79; P < .0001). The optimal gas exchange model included ΔV.o2/ΔWR < 8.6; V.e/V.co2 slope to peak V.o2 ratio ≥ 2.7, and periodic breathing (AUC of 0.84; P < .0001). CONCLUSIONS: The best single gas exchange parameter to discriminate between circulatory problems and deconditioning is V.e/V.co2 slope to peak V.O2 ratio. Combining it with ΔV.o2/ΔWR and periodic breathing improves the discriminative ability.


Subject(s)
Cardiovascular Deconditioning/physiology , Echocardiography, Stress , Exercise Test , Heart Failure/physiopathology , Stroke Volume , Ventricular Dysfunction, Left/physiopathology , Aged , Anaerobic Threshold , Breath Tests , Carbon Dioxide , Diagnosis, Differential , Echocardiography , Female , Heart Failure/diagnosis , Humans , Male , Middle Aged , Oxygen Consumption/physiology , Ventricular Dysfunction, Left/diagnosis
8.
J Musculoskelet Neuronal Interact ; 16(2): 84-91, 2016 06 07.
Article in English | MEDLINE | ID: mdl-27282452

ABSTRACT

OBJECTIVES: We review the studies that have evaluated intermittent short-radius centrifugation as a potential countermeasure for cardiovascular, musculoskeletal, and sensorimotor deconditioning in simulated weightlessness. METHODS: The findings from 18 experimental protocols that have used bed rest and dry immersion for comparing the protective effects of centrifugation versus standing upright or walking, and the effects of continuous vs. periodic exposure to centrifugation are discussed. RESULTS: Centrifugation for as little as 30 min per day was found to be effective in mitigating orthostatic intolerance and strength in postural muscle after 5 days of bed rest, but it was not effective in mitigating plasma volume loss. CONCLUSION: To determine the optimal prescription for centrifugation as a countermeasure, we recommend further studies using (a) bed rest of longer duration, (b) individualized prescriptions of centrifugation combined with exercise, and


Subject(s)
Weightlessness Countermeasures , Weightlessness Simulation , Bed Rest , Cardiovascular Deconditioning/physiology , Centrifugation , Humans
9.
Aviakosm Ekolog Med ; 50(1): 13-6, 2016.
Article in Russian | MEDLINE | ID: mdl-27344852

ABSTRACT

The authors present the results of retrospective analysis of earlier published papers and reports, and also own observations of cardiovascular deconditioning in cosmonauts and astronauts returning from microgravity. Benefits of in-flight physical exercises to g-tolerance during descent and post-recovery orthostatic stability are discussed.


Subject(s)
Aerospace Medicine , Cardiovascular Deconditioning/physiology , Hypotension, Orthostatic/physiopathology , Weightlessness , Astronauts , Humans , Space Flight , Weightlessness/adverse effects
10.
Scand J Med Sci Sports ; 26(6): 620-9, 2016 Jun.
Article in English | MEDLINE | ID: mdl-25946038

ABSTRACT

This study examined the time course of short-term training and detraining-induced changes in oxygen uptake ( V ˙ O 2 ) kinetics. Twelve men (24 ± 3 years) were assigned to either a 50% or a 70% of V ˙ O 2 m a x training intensity (n = 6 per group). V ˙ O 2 was measured breath-by-breath. Changes in deoxygenated-hemoglobin concentration (Δ[HHb]) were measured by near-infrared spectroscopy. Moderate-intensity exercise on-transient V ˙ O 2 and Δ[HHb] were modeled with a mono-exponential and normalized (0-100% of response) and the [ H H b ] / V ˙ O 2 ratio was calculated. Similar changes in time constant of V ˙ O 2 ( t V ˙ O 2 ) were observed in both groups. The combined group mean for t V ˙ O 2 decreased ∼14% (32.3 to 27.9 s, P < 0.05) after one training session with a further ∼11% decrease (27.9 to 24.8 s, P < 0.05) following two training sessions. The t V ˙ O 2 p remained unchanged throughout the remaining of training and detraining. A significant "overshoot" in the [ H H b ] / V ˙ O 2 ratio was decreased (albeit not significant) after one training session, and abolished (P < 0.05) after the second one, with no overshoot observed thereafter. Speeding of V ˙ O 2 kinetics was remarkably quick with no further changes being observed with continuous training or during detraining. Improve matching of local O2 delivery to O2 utilization is a mechanism proposed to influence this response.


Subject(s)
Oxygen Consumption , Oxygen/metabolism , Physical Conditioning, Human/physiology , Physical Fitness/physiology , Adult , Cardiovascular Deconditioning/physiology , Exercise Test , Hemoglobins/metabolism , Humans , Kinetics , Male , Physical Conditioning, Human/methods , Pulmonary Gas Exchange , Quadriceps Muscle/metabolism , Young Adult
11.
South Med J ; 107(3): 144-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24937330

ABSTRACT

OBJECTIVES: Gas exchange measurements obtained during submaximal exercise have been shown to provide prognostic and diagnostic information in patients with heart failure (HF) and to differentiate heart versus lung limitations in patients with unexplained dyspnea. The aim of our study was to assess the clinical utility of submaximal cardiopulmonary exercise testing using the Shape-HF equipment in identifying the cause of unexplained dyspnea. METHODS: A total of 65 patients underwent Shape-HF tests from September 2010 to June 2011 for unexplained dyspnea at our center. RESULTS: Of 65 patients, 39 were men and 26 were women. In this study, 23 patients had preexisting asthma or chronic obstructive pulmonary disease (COPD); 19 patients had a pacemaker (8), an implantable cardioverter defibrillator (2), or a cardiac resynchronization therapy defibrillator (CRT-D) (9). The study revealed that submaximal cardiopulmonary exercise testing provided supportive clinical data for deconditioning, pulmonary limitations (eg, COPD, interstitial lung disease, sleep apnea), pulmonary hypertension, and chronotropic incompetence in 21.5%, 23.1%, 13.8%, and 6.2% of patients, respectively. Pulmonary hypertension was confirmed in 55% of patients by echocardiography and lung problems were confirmed in 40% of patients by pulmonary function test and sleep study. Of nine patients with an implanted CRT-D, optimization of atrioventricular and interventricular programming was performed in seven (78%) using gas exchange monitoring while performing a steady state, low-level treadmill walk. CONCLUSIONS: Submaximal cardiopulmonary exercise testing has strongly suggested the diagnosis of COPD, interstitial lung disease, pulmonary hypertension, and deconditioning and has led to appropriate testing. Based on prior studies, we also used Shape-HF for its approved purpose of optimizing CRT-D programming in patients with HF, leading to clinical improvement.


Subject(s)
Dyspnea/diagnosis , Exercise Test , Cardiovascular Deconditioning/physiology , Dyspnea/etiology , Dyspnea/physiopathology , Exercise Test/methods , Female , Humans , Hypertension, Pulmonary/complications , Hypertension, Pulmonary/diagnosis , Lung Diseases, Interstitial/complications , Lung Diseases, Interstitial/diagnosis , Male , Middle Aged , Pacemaker, Artificial , Pulmonary Disease, Chronic Obstructive/complications , Pulmonary Disease, Chronic Obstructive/diagnosis
12.
Med Biol Eng Comput ; 52(1): 53-64, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24096595

ABSTRACT

Cardiovascular deconditioning has long been recognized as a characteristic of the physiological adaptation to long-term bed rest in patients. The process is thought to contribute to orthostatic intolerance and enhance secondary complications in a significant way. Mobilization is a cost-effective and simple method to maintain the cardiovascular parameters (i.e., blood pressure, heart rate) stable, counter orthostatic intolerance and reduce the risk of secondary problems in patients during long-term immobilization. The aim of this project is to control the cardiovascular parameters such as heart rate and blood pressure of bed rest patients via automated leg mobilization and body tilting. In a first step, a nonlinear model predictive control strategy was designed and evaluated on five healthy subjects and 11 bed rest patients. In a next step, a clinically feasible study was conducted on two patients. The mean values differed on average less than 1 bpm from the predetermined heart rate and less than 2.5 mmHg from the desired blood pressure values. These results of the feasibility study are promising, although heterogeneous disease etiologies and individual medication strongly influence the mechanically induced reactions. The long-term goal is an automation of the control of physiological signals and the mobilization of bed rest patients in an early phase of the rehabilitation process. Therefore, this new approach could help to strengthen the cardiovascular system and prevent secondary health problems arising from long-term bed rest.


Subject(s)
Bed Rest/adverse effects , Cardiovascular System/physiopathology , Adult , Aged , Aged, 80 and over , Beds , Blood Pressure/physiology , Cardiovascular Deconditioning/physiology , Female , Heart Rate/physiology , Humans , Male , Middle Aged , Young Adult
14.
Biochem Cell Biol ; 91(5): 309-14, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24032680

ABSTRACT

Individuals exposed to extended periods of spaceflight or prolonged 6° head-down-tilt bed rest often suffer from health hazards represented by cardiovascular deconditioning. Many studies have reported that alterations in vascular endothelial cells contribute to cardiovascular dysfunction induced by microgravity. Autophagy, a lysosomal degradation pathway, serves an adaptive role for survival, differentiation, and development in cellular homeostasis, and can be triggered by various environmental stimuli. However, whether autophagy can be induced in endothelial cells by real or simulated microgravity remains to be determined. This study was designed to investigate the effects of simulated microgravity on the activation of autophagy in human umbilical vein endothelial cells (HUVECs). We report here that clinorotation, a simulated model of microgravity, enhances autophagosome formation, increases LC3 and beclin-1 expression, and promotes the conversion of LC3-I to LC3-II in HUVECs. These results demonstrate that simulated microgravity for 48 h activates autophagy of vascular endothelial cells.


Subject(s)
Autophagy , Human Umbilical Vein Endothelial Cells/metabolism , Rotation/adverse effects , Weightlessness/adverse effects , Apoptosis Regulatory Proteins/biosynthesis , Beclin-1 , Cardiovascular Deconditioning/physiology , Cell Line , Humans , Membrane Proteins/biosynthesis , Microtubule-Associated Proteins/biosynthesis , Microtubule-Associated Proteins/metabolism , Space Flight
15.
Eur J Phys Rehabil Med ; 49(6): 765-74, 2013 Dec.
Article in English | MEDLINE | ID: mdl-23877228

ABSTRACT

BACKGROUND: Guidelines for optimal exercise doses in people with multiple sclerosis (MS) have to be established. We need to ascertain the basic physiological and perceptual response and adaptation to different exercise doses in this clinical population. AIM: The aim of this paper was to explore the response during maximal and sub-maximal exercise in people with MS prior to and following two different twelve week exercise programmes. DESIGN: Sub-analysis of per protocol exercise data of a two group, single blinded, randomised control trial. SETTING: Multicentre (community leisure and rehabilitation centres). POPULATION: Participants with MS assigned to a continuous (N.=12; mean±SE age=52.3±2.08; Barthel index median & range=19&13-20) or interval (N.=9; mean±SE age=49.3±3.5; Barthel index median & range=19&18-20) exercise programme. METHODS: Cardiovascular, respiratory and perceptual exercise response and adaption was measured at maximal and sub-maximal levels of physical exercise prior to and following a twelve week exercise programme, delivered at different intensities. RESULTS: Irrespective of the type of exercise programme followed, there was a significant increase in peak power (z=-1.98; P=0.05) and normalised oxygen uptake during unloaded cycling (z =-2.00; P=0.05). At discharge from the exercise programmes, the cardiovascular response to sub-maximal exercise had significantly changed (t(360) =-4.62; p<0.01). CONCLUSION: The response in people with MS at maximal and sub-maximal levels of physical exercise following a twelve week programme is analogous to non-diseased adults. CLINICAL REHABILITATION IMPACT: Cardiovascular adaptation in people with MS following a twelve week exercise programme suggests deconditioning rather than autonomic dysfunction caused by the disease.


Subject(s)
Adaptation, Physiological , Cardiovascular Deconditioning/physiology , Exercise Therapy/methods , Exercise Tolerance/physiology , Multiple Sclerosis/rehabilitation , England , Humans , Middle Aged , Multiple Sclerosis/complications , Oxygen Consumption
16.
Psychosom Med ; 75(4): 375-81, 2013 May.
Article in English | MEDLINE | ID: mdl-23630307

ABSTRACT

OBJECTIVE: Exercise has widely documented cardioprotective effects, but the mechanisms underlying these effects are not entirely known. Previously, we demonstrated that aerobic but not strength training lowered resting heart rate and increased cardiac vagal regulation, changes that were reversed by sedentary deconditioning. Here, we focus on the sympathetic nervous system and test whether aerobic training lowers levels of cardiovascular sympathetic activity in rest and that deconditioning would reverse this effect. METHODS: We conducted a randomized controlled trial contrasting the effects of aerobic (A) versus strength (S) training on indices of cardiac (preejection period, or PEP) and vascular (low-frequency blood pressure variability, or LF BPV) sympathetic regulation in 149 young, healthy, and sedentary adults. Participants were studied before and after conditioning, as well as after 4 weeks of sedentary deconditioning. RESULTS: As previously reported, aerobic capacity increased in response to conditioning and decreased after deconditioning in the aerobic, but not the strength, training group. Contrary to prediction, there was no differential effect of training on either PEP (A: mean [SD] -0.83 [7.8] milliseconds versus S: 1.47 [6.69] milliseconds) or LF BPV (A: mean [SD] -0.09 [0.93] ln mm Hg(2) versus S: 0.06 [0.79] ln mm Hg(2)) (both p values > .05). CONCLUSIONS: These findings, from a large randomized controlled trial using an intent-to-treat design, show that moderate aerobic exercise training has no effect on resting state cardiovascular indices of PEP and LF BPV. These results indicate that in healthy, young adults, the cardioprotective effects of exercise training are unlikely to be mediated by changes in resting sympathetic activity. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT00358137.


Subject(s)
Cardiovascular Deconditioning/physiology , Cardiovascular System/innervation , Exercise , Resistance Training , Sympathetic Nervous System/physiology , Adolescent , Adult , Blood Pressure/physiology , Female , Heart Rate/physiology , Humans , Male , Middle Aged , Reference Values , Sedentary Behavior , Vagus Nerve/physiology , Young Adult
17.
Support Care Cancer ; 21(3): 873-81, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23052910

ABSTRACT

PURPOSE: Fatigue is one of the most commonly reported side effects during treatment for breast cancer and can persist following treatment completion. Cancer-related fatigue after treatment is multifactorial in nature, and one hypothesized mechanism is cardiorespiratory and neuromuscular deconditioning. The purpose of this study was to compare cardiorespiratory and neuromuscular function in breast cancer survivors who had completed treatment and met the specified criteria for cancer-related fatigue and a control group of breast cancer survivors without fatigue. METHODS: Participants in the fatigue (n = 16) and control group (n = 11) performed a maximal exercise test on a cycle ergometer for determination of peak power, power at lactate threshold, and VO(2) peak. Neuromuscular fatigue was induced with a sustained submaximal contraction of the right quadriceps. Central fatigue (failure of voluntary activation) was evaluated using twitch interpolation, and peripheral fatigue was measured with an electrically evoked twitch. RESULTS: Power at lactate threshold was lower in the fatigue group (p = 0.05). There were no differences between groups for power at lactate threshold as percentage of peak power (p = 0.10) or absolute or relative VO(2) peak (p = 0.08 and 0.33, respectively). When adjusted for age, the fatigue group had a lower power at lactate threshold (p = 0.02) and absolute VO(2) peak (p = 0.03). There were no differences between groups in change in any neuromuscular parameters after the muscle-fatiguing protocol. CONCLUSIONS: Findings support the hypothesis that cardiorespiratory deconditioning may play a role in the development and persistence of cancer-related fatigue following treatment. Future research into the use of exercise training to reduce cardiorespiratory deconditioning as a treatment for cancer-related fatigue is warranted to confirm these preliminary findings.


Subject(s)
Breast Neoplasms/therapy , Fatigue/etiology , Muscle Fatigue/physiology , Adult , Aged , Anaerobic Threshold , Cardiovascular Deconditioning/physiology , Exercise Test , Female , Humans , Lactic Acid/blood , Middle Aged , Muscle Contraction/physiology , Oxygen Consumption/physiology , Quadriceps Muscle/metabolism , Survivors
18.
PM R ; 4(11): 857-61, 2012 Nov.
Article in English | MEDLINE | ID: mdl-23174550

ABSTRACT

Rehabilitation specialists have a unique opportunity to serve as the drivers of change in promoting the use of exercise facilities by people with newly acquired disabilities. Identifying programs that are effective and sustainable for extending recovery in a community-based exercise facility after rehabilitation may reduce the risk of secondary health complications and optimize health and function. This article describes an approach for closing the gap between inpatient and outpatient rehabilitation and the use of community-based exercise facilities by people with disabilities. Extending recovery from rehabilitation to community-based exercise requires a transitional setting (eg, hospital-based fitness facilities and specialized fitness centers and programs for people with disabilities) that provides greater support and supervision in teaching individuals with disabilities (and, when necessary, their caregivers) how to exercise safely and effectively and access the programs, equipment, and services available in these facilities. With the shortened amount of rehabilitation time that many patients are given after acquiring a disability or being treated for a new health condition, community-based exercise facilities and the fitness professionals who are employed in them must become part of the rehabilitation continuum and obtain additional training to better serve the needs of people with newly acquired disabilities who are leaving rehabilitation.


Subject(s)
Disabled Persons/rehabilitation , Exercise/physiology , Health Promotion , Architectural Accessibility , Cardiovascular Deconditioning/physiology , Certification , Humans , Sedentary Behavior , Social Participation
19.
Neurology ; 79(14): 1435-9, 2012 Oct 02.
Article in English | MEDLINE | ID: mdl-22993288

ABSTRACT

OBJECTIVE: To study the frequency and degree of deconditioning, clinical features, and relationship between deconditioning and autonomic parameters in patients with orthostatic intolerance. METHODS: We retrospectively studied all patients seen for orthostatic intolerance at Mayo Clinic between January 2006 and June 2011, who underwent both standardized autonomic and exercise testing. RESULTS: A total of 184 patients (84 with postural orthostatic tachycardia syndrome [POTS] and 100 without orthostatic tachycardia) fulfilled the inclusion criteria. Of these, 89% were women, and median age was 27.5 years (interquartile range [IQR] 22-37 years). Symptom duration was 4 years (IQR 2-7.8). Of the patients, 90% had deconditioning (reduced maximum oxygen uptake [VO(2max)%] <85%) during exercise. This finding was unrelated to age, gender, or duration of illness. The prevalence of deconditioning was similar between those with POTS (95%) and those with orthostatic intolerance (91%). VO(2max)% had a weak correlation with a few autonomic and laboratory parameters but adequate predictors of VO(2max)% could not be identified. CONCLUSION: Reduced VO(2max)% consistent with deconditioning is present in almost all patients with orthostatic intolerance and may play a central role in pathophysiology. This finding provides a strong rationale for retraining in the treatment of orthostatic intolerance. None of the autonomic indices are reliable predictors of deconditioning.


Subject(s)
Cardiovascular Deconditioning/physiology , Orthostatic Intolerance/complications , Postural Orthostatic Tachycardia Syndrome/complications , Adult , Blood Pressure , Exercise Test , Female , Heart Rate , Humans , Male , Reflex , Retrospective Studies , Statistics, Nonparametric , Valsalva Maneuver/physiology , Young Adult
20.
Ann Phys Rehabil Med ; 55(5): 294-311, 2012 Jul.
Article in English, French | MEDLINE | ID: mdl-22705094

ABSTRACT

OBJECTIVES: To establish the level of maximal aerobic capacity in patients with chronic pain of different etiologies and to compare these results with different parameters of disability. PATIENTS AND METHODS: A cycloergometer exercise test with VO(2)max measurement, fatigue assessment and objective and subjective disability parameter testing was performed on 155 patients (mean age 42.1 ± 9.9 years) classified into three groups: patients with chronic lower back pain, patients with an upper limb musculoskeletal disorder, and patients with multifocal chronic pain. RESULTS: The mean VO(2)max value was 22.18 mL/min/kg. There was no statistically significant difference in VO(2)max between the three groups. The patients with poorest aerobic condition were older (P<0.007), were on sick leave longer (P<0.03), had weaker Sorensen test (P<0.01) and P.I.L.E. (P<0.004) results, had more perceived fatigue (P<0.04), a higher mean BMI (P<0.0001) and gained more weight during sick leave (P<0.02). DISCUSSION: Numerous studies have examined loss of aerobic capacity due to chronic low back pain with contradictory results. This is probably due to variability of in the methods used to measure or calculate VO(2)max as well as to the variability in the studied populations. CONCLUSION: It seems appropriate to offer patients with chronic pain multidisciplinary exercise rehabilitation programs.


Subject(s)
Cardiovascular Deconditioning/physiology , Chronic Pain/physiopathology , Disability Evaluation , Oxygen Consumption , Adult , Aerobiosis , Age Factors , Arm , Chronic Pain/metabolism , Chronic Pain/psychology , Exercise Test , Fatigue/diagnosis , Fatigue/physiopathology , Female , Humans , Low Back Pain/metabolism , Low Back Pain/physiopathology , Low Back Pain/psychology , Male , Middle Aged , Musculoskeletal Diseases/metabolism , Musculoskeletal Diseases/physiopathology , Sick Leave , Weight Lifting
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