Exercise Testing In Individuals Research Articles

Blood pressure response during exercise testing in individuals with and without hypertension: The value of the recovery phase.

Hypertension and exercise testing are essential for cardiovascular risk assessment. However, an exact description of blood pressure (BP) in patients with a hypertensive response during exercise (HRE), especially in the recovery phase is lacking. Herein, we aimed to analyse BP and heart rate during exercise testing and recovery in patients with an HRE. 800 patients aged 17-90 with an HRE during a standardized bicycle ergometry test were recruited. The BP behaviour during exercise testing was correlated with clinical data. Furthermore, data were analysed according to the presence of pre-existent hypertension. Of the 800 patients included in this study 497 (62%) were previously diagnosed with hypertension. Analysis of covariance showed a significantly faster systolic (β [95% CI] 8.0 [4.9-11.1]) and diastolic (2.4 [0.4-4.4]) BP recovery 3 min after maximal exercise in patients without hypertension in univariable models. These results remained robust in fully adjusted models taking into account age, sex, body mass index, cardiovascular disease, and antihypertensive treatment for systolic (5.3 [1.2-9.4]) and diastolic BP (4.5 [1.9-7.0]). Furthermore, patients with hypertension displayed higher systolic BP during maximal exercise in univariable (3.8 [0.1-7.5]) and fully adjusted (5.5 [1.1-10.0]) models. There was no difference in maximum diastolic BP between groups. In this large cohort study, patients without hypertension showed a faster systolic and diastolic BP recovery and lower maximal systolic BP compared to patients with hypertension. Overall, this study provides new insights into cardiovascular health during recovery phase.

EXPLORING THE ROLE OF SKELETAL MUSCLE MICROVASCULAR BLOOD FLOW IN EXERCISE CAPACITY AMONG INDIVIDUALS WITH CONTROLLED TYPE 2 DIABETES

INTRODUCTION & AIMS The cardiac and macrovascular system is vital for human exercise capacity, yet the microvascular network is primarily responsible for delivering nutrients and oxygen to metabolically active tissues like skeletal muscle. Due to methodological limitations, few studies have investigated the role of muscle microvascular blood flow in determining exercise capacity or intolerance in individuals with chronic conditions such as type 2 diabetes. Our aim was to use modern contrast-enhanced ultrasound to directly measure microvascular blood flow in skeletal muscle at rest and after a maximal treadmill exercise test in individuals with controlled type 2 diabetes. METHODS Fifteen adults with controlled type 2 diabetes (age: 62.5 ± 8.0 years [M ± SD]; BMI: 31.6 ± 6.9 kg/m2; HbA1c: 6.7 ± 0.9%; 13 females and 2 male) attended the laboratory after a 2-hour fast and completed a Modified Bruce treadmill exercise test until exhaustion. Microvascular blood velocity, volume, and flow in the vastus lateralis muscle was assessed at rest, immediately post-exercise, and 30 minutes post-exercise via contrast-enhanced ultrasound during a constant-rate intravenous contrast agent infusion (DEFINITY®). Participants also completed a whole-body dual x-ray absorptiometry scan and a six-minute walk test (6MWT). RESULTS Microvascular blood velocity, volume, and flow increased immediately after exercise (∼230%, ∼79%, and ∼529%, respectively; all p<0.001), and remained elevated above baseline levels 30 minutes post-exercise (∼79%, ∼25%, and ∼139%, respectively; all p≤0.003). Resting and post-exercise skeletal muscle microvascular blood flow measures were not associated with VO2peak (ml/min/kg), time to exhaustion, or six-minute walk distance (all p>0.05). CONCLUSION Muscle microvascular blood flow remains elevated for up to 30 minutes following maximal aerobic exercise in individuals with controlled type 2 diabetes. The lack of association between muscle microvascular blood flow and exercise capacity is not clear but may indicate considerable blood flow redundancy or reserve within the vascular network.

Metabolic and physiological responses to graded exercise testing in individuals with type 1 diabetes using insulin pump therapy.

To profile acute glycaemic dynamics during graded exercise testing (GXT) and explore the influence of glycaemic indicators on the physiological responses to GXT in adults with type 1 diabetes using insulin pump therapy. This was a retrospective analysis of pooled data from four clinical trials with identical GXT protocols. Data were obtained from 45 adults with type 1 diabetes using insulin pumps [(30 females); haemoglobin A1c 59.5 ± 0.5 mmol/mol (7.6 ± 1.0%); age 49.7 ± 13.0 years; diabetes duration 31.2 ± 13.5 years; V̇O2peak 29.5 ± 8.0ml/min/kg]. Integrated cardiopulmonary variables were collected continuously via spiroergometry. Plasma glucose was obtained every 3 min during GXT as well as the point of volitional exhaustion. Data were assessed via general linear modelling techniques with age and gender adjustment. Significance was accepted at p ≤ .05. Despite increasing duration and intensity, plasma glucose concentrations remained similar to rest values (8.8 ± 2.3 mmol/L) throughout exercise (p= .419) with an overall change of +0.3± 1.1 mmol/L. Starting glycaemia bore no influence on subsequent GXT responses. Per 1% increment in haemoglobin A1c there was an associated decrease in V̇O2peak of 3.8ml/min/kg (p< .001) and powerpeak of 0.33 W/kg (p< .001) concomitant with attenuations in indices of peripheral oxygen extraction [(O2 pulse) -1.2ml/beat, p= .023]. In adults with long-standing type 1 diabetes using insulin pump therapy, circulating glucose remains stable during a graded incremental cycle test to volitional exhaustion. Glycaemic indicators are inversely associated with aerobic rate, oxygen economy and mechanical output across the exercise intensity spectrum. An appreciation of these nexuses may help guide appropriate decision making for optimal exercise management strategies.

Cardiopulmonary reserve examined with cardiopulmonary exercise testing in individuals with chronic kidney disease: A systematic review and meta-analysis.

Patients with chronic kidney disease (CKD) often present reduced physical activity and exercise tolerance due to factors relevant to co-existing disturbances of the cardiac, nervous and muscular systems. Cardiopulmonary exercise testing (CPET) is used for clinical evaluation of exercise limitation and related symptoms (i.e., dyspnea, fatigue) in several medical fields. This is a systematic review and meta-analysis of studies using CPET technology to examine cardiopulmonary reserve in individuals with versus without CKD. Literature search involved PubMed, Web of Science and Scopus databases; manual search of article references and of gray literature was also performed. Observational studies and randomized trials that used CPET for patients with CKD stage 1-5 versus controls were eligible. The primary outcome was peak oxygen uptake (VO2peak). The Newcastle-Ottawa Scale was used to evaluate the quality of retrieved studies. From an initial 4944 literature records, we identified 29 studies fulfilling the inclusion criteria; of these, 25 studies (2,213 participants) with complete data were included in the final meta-analysis. VO2peak was significantly lower in CKD patients than controls without CKD [standardized mean difference (SMD) -1.40, 95% confidence interval (CI) -1.68; -1.13)]. Values were lower for CKD than non-CKD individuals for oxygen consumption at anaerobic threshold (SMD -1.06, 95% CI -1.34; -0.79) and maximum workload [weighted mean difference (WMD) -58.26, 95% CI 74.14; -42.38]. In 3 studies, CKD patients had higher VO2peak than controls with heart failure without CKD (WMD 6.60, 95% CI 3.02; 10.18). Sensitivity analyses confirmed the robustness of these findings. VO2peak and other commonly analyzed CPET variables were lower in patients with CKD than controls, which indicates reduced functional cardiopulmonary reserve in CKD. In contrast, patients with CKD performed better than controls with heart failure without CKD. Overall, rehabilitation programs should be more widely applied to individuals with CKD. CRD42021227805.

How to Score the Peak Oxygen Consumption Obtained Through Cardiopulmonary Exercise Test in Individuals after Stroke?

ObjectivesTo compare five distinct methods to score the peak of oxygen consumption (VO2peak) obtained through the cardiopulmonary exercise testing (CPET) in individuals after stroke. Materials and methodsThe VO2peak was obtained through the CPET with five methods: method-1: the highest value of the test; method-2: the highest value of the last 30 seconds at peak exercise; method-3: the mean of the last 30 seconds at peak exercise; method-4: the mean of the last 20 seconds at peak exercise; method-5: the highest value averaged of the 3 last blocks of 10 seconds at peak exercise. The coefficient of variance (CV) and the mean differences with 95% confidence interval (CI) between the scoring methods were calculated. A post-hoc test (Tukey HSD) was performed to calculate the adjusted 95%CI. ResultsFifty-nine individuals were included (54±12 years, 56±60 months after stroke). The CV of the methods 1-to-5 were, respectively: 27.91%, 25.77%, 23.38%, 23.83%, and 23.33%. There was no difference between method-1 and method-2 (95%CI: -1.10 to 4.69) and between methods 3 to 5: method-3 and method-4 (95%CI: -2.97 to 2.82); method-3 and method-5 (95%CI: -3.57 to 2.22); method-4 and method-5 (95%CI: -3.49 to 2.30). However, method-1 and -2 provided VO2peak values different from that of methods 3-to-5. ConclusionsThe scoring method of obtaining the VO2peak has an influence on its magnitude. Since methods 3-to-5 showed lower CV and provided similar values, they should be used to calculate the VO2peak obtained through the CPET in individuals after stroke.

Upper Limb Energy Demand During Unilateral Arm Crank Submaximal Exercise Testing in Individuals With Chronic Stroke

ObjectiveTo investigate upper limb (UL) energy demand during unilateral arm crank submaximal exercise testing in individuals with stroke compared with healthy controls and the relationship between UL energy demand and UL activity in individuals with stroke. DesignCross-sectional, observational study. SettingResearch laboratory. ParticipantsIndividuals with chronic stroke (n=14) and controls (n=12), matched for age, sex, and body mass index (N=26). InterventionsNot applicable. Main Outcome MeasuresUL energy demand was measured as peak oxygen consumption (V̇o2)/peak load during unilateral arm crank submaximal exercise testing. UL activity was measured using the Box and Block Test (BBT) and Grooved Pegboard Test (GPT). ResultsThe energy demand of the paretic side compared with the nonparetic side of the stroke group was 0.43 mL/kg/min/W (95% confidence interval, 0.03-0.83, P=.005) greater than the dominant compared with the nondominant side of the control group. The median difference between sides in peak V̇o2/peak load was 52% for the group with stroke compared with 11% for the control group. Positive correlations between the median percentage difference between the paretic and the nonparetic side of peak V̇o2/peak load and BBT were 0.72 (P=.004) and of V̇o2/peak load and GPT was 0.77 (P=.002). ConclusionsThe higher energy demand of the paretic UL during unilateral arm crank submaximal exercise testing than the nonparetic and both UL of the controls together with the strong relationship between energy demand and UL activity suggest that the energy demand of the paretic UL has the potential to affect real-life UL activity after stroke.

Properties of measurements obtained during cardiopulmonary exercise testing in individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Diminished cardiopulmonary exercise test (CPET) performance indicates the physiological basis for reduced capacity for activities of daily living and work. Thus, it may be a biomarker for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). To determine statistical properties of cardiac, pulmonary, and metabolic measurements obtained during CPET in people with ME/CFS. Fifty-one females with ME/CFS and 10 sedentary females with similar age and body mass received cardiac, pulmonary, and metabolic measurements during 2 CPETs separated by 24 hours. Two-way analysis of variance and effect size calculations (Cohen's d) were used to assess the magnitude and statistical significance of differences in measurements between groups. Reliability of CPET measurements was estimated using intraclass correlation coefficients (ICC2,1). Responsiveness of CPET measurements was assessed using minimum detectable change outside the 95% confidence interval (MDC95) and coefficients of variation (CoV). CPET measurements demonstrated moderate to high reliability for individuals with ME/CFS. Comparing subjects with ME/CFS and control subjects yielded moderate to large effect sizes on all CPET measurements. MDC95 for all individuals with ME/CFS generally exceeded control subjects and CoVs for CPET measurements were comparable between groups. CPET measurements demonstrate adequate responsiveness and reproducibility for research and clinical applications.

Veterans with Gulf War Illness exhibit distinct respiratory patterns during maximal cardiopulmonary exercise.

IntroductionThe components of minute ventilation, respiratory frequency and tidal volume, appear differentially regulated and thereby afford unique insight into the ventilatory response to exercise. However, respiratory frequency and tidal volume are infrequently reported, and have not previously been considered among military veterans with Gulf War Illness. Our purpose was to evaluate respiratory frequency and tidal volume in response to a maximal cardiopulmonary exercise test in individuals with and without Gulf War Illness.Materials and methods20 cases with Gulf War Illness and 14 controls participated in this study and performed maximal cardiopulmonary exercise test on a cycle ergometer. Ventilatory variables (minute ventilation, respiratory frequency and tidal volume) were obtained and normalized to peak exercise capacity. Using mixed-design analysis of variance models, with group and time as factors, we analyzed exercise ventilatory patterns for the entire sample and for 11 subjects from each group matched for race, age, sex, and height.ResultsDespite similar minute ventilation (p = 0.57, η2p = 0.01), tidal volume was greater (p = 0.02, η2p = 0.16) and respiratory frequency was lower (p = 0.004, η2p = 0.24) in Veterans with Gulf War Illness than controls. The findings for respiratory frequency remained significant in the matched subgroup (p = 0.004, η2p = 0.35).ConclusionIn our sample, veterans with Gulf War Illness adopt a unique exercise ventilatory pattern characterized by reduced respiratory frequency, despite similar ventilation relative to controls. Although the mechanism(s) by which this pattern is achieved remains unresolved, our findings suggest that the components of ventilation should be considered when evaluating clinical conditions with unexplained exertional symptoms.

Validity and reliability of the unsupported upper-limb exercise test in individuals with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic disease which affects the performance of the upper extremities. There is no method to evaluate the specific upper extremity endurance of individuals with this disease. The unsupported upper-limb exercise test (UULEX) is a performance test that evaluates upper extremity performance (functionality and endurance). The aim of this study was to examine the reliability and validity of UULEX and the minimal detectable change (MDC) in individuals with RA. The study included 71 patients (15 male, 56 female) with a mean age of 52.15±10.11years. The intraclass correlation coefficient (ICC) was used to assess the reliability of UULEX. MDC estimates were calculated using baseline data. Correlations of UULEX with the Disability of Arm, Shoulder and Hand Questionnaire (DASH), Health Assessment Questionnaire (HAQ), 30-second push-up test and 6 pegboard ring test (6PBRT) were assessed for concurrent validity. The level, weight and duration scores of the UULEX test were found to be excellent for intra-rater reliability (ICC=0.922, 0.960, 0.958). Intra-rater MDC values were determined to be 0.35, 2.04, and 0.80seconds, respectively. Moderate-excellent correlations were found between UULEX and DASH, HAQ, 30-second push-up test and 6PBRT (P < .05). The results of this study showed that UULEX test is a valid and reliable method for the assessment of upper extremity performance in individuals with RA.

Reproducibility of Measurements Obtained During Cardiopulmonary Exercise Testing in Individuals With Fatiguing Health Conditions: A Case Series

Purpose: Measurements obtained during maximal cardiopulmonary exercise testing (CPET) demonstrate high test–retest reliability, which indicates low error variance. However, measurements obtained from people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may depart from typically observed high reproducibility, which could represent functionally relevant biological variability that is characteristic of the underlying pathophysiology. The purpose of this case series was to document individual experiences with test–retest variability in CPET measurements in individuals with ME/CFS compared with other fatiguing health conditions. Methods: In this case series, 6 women matched for age and body mass index underwent 2 maximal CPETs spaced 24 hours apart. Clients comprised 1 sedentary individual without fatigue, 1 active individual without fatigue, 1 individual with multiple sclerosis (MS), 1 individual diagnosed with HIV, 1 individual with ME/CFS and low maximal volume of oxygen consumed (VO2max), and 1 high-functioning individual with ME/CFS and high VO2max. Percent change in CPET measurements between tests was calculated for each client. Results: Nondisabled clients and clients with MS and HIV reproduced or improved in their volume of oxygen consumed (VO2), workload (WL), heart rate (HR), and minute ventilation (VE) at ventilatory anaerobic threshold (VAT) and at peak exercise (except peak WL and VE for the individual with HIV). Neither individual with ME/CFS reproduced VO2, WL, HR, or VE at VAT within literature estimates. Conclusions: Measurements during CPET for individual patients may relate to potential condition-specific deficits in cardiac, pulmonary, and metabolic functioning.

Exercise Testing in Individuals With Diabetes, Practical Considerations for Exercise Physiologists.

Exercise and sports activities are crucial for individuals with diabetes. Diabetic patients are often referred to sports clinics for cardiopulmonary exercise testing to evaluate physical capacity, exercise-related symptoms, or to obtain medical clearance. While there is an abundance of literature on cardiopulmonary testing, practical recommendations for exercise physiologists and sports clinic specialists performing exercise testing for this specific population are lacking. The goal of this report is to provide a practical framework to understand, prepare, and perform exercise testing in patients with diabetes, maximizing exercise physiology outcomes, diagnostic value, and ensuring safety.

Lactate Response During Graded Exercise Test In Individuals With Prediabetes After Aerobic Exercise Training

Lactate Response During Graded Exercise Test In Individuals With Prediabetes After Aerobic Exercise Training

Cardiopulmonary Profile of Individuals with Intellectual Disability.

Individuals with intellectual disabilities (ID) are often sedentary and have low fitness levels. Current knowledge supports the existence of physiological barriers resulting in low fitness and exercise intolerance in individuals with Down syndrome, which might be applicable to other ID etiologies. If physiological barriers exist in ID, this would require adaptation of the physical activity guidelines. The aim of this study was to assess differences in cardiopulmonary profiles, including maximal oxygen uptake, during a cardiopulmonary exercise test in individuals with ID without Down syndrome and healthy controls. Participants performed an incremental cardiopulmonary exercise test on a treadmill until exhaustion. Outcomes were peak heart rate (HRpeak), absolute peak oxygen uptake (V˙O2peak), relative V˙O2peak, peak minute ventilation, peak CO2 expenditure, oxygen uptake efficiency slope, V˙E/V˙CO2 slope, absolute O2 pulse, relative O2 pulse, difference from predicted HRpeak, HR reserve, RERpeak, ventilatory threshold (VT), and VT as a percentage of V˙O2peak. Differences between groups were analyzed with Student's t-tests and multiple linear regression after adjusting for potential confounders (sex, age, body mass index, and activity level). Individuals with ID had worse outcomes on all of the cardiopulmonary outcomes, except for VT expressed as a percentage of V˙O2peak and V˙E/V˙CO2 slope (P < 0.05). Having ID was an independent predictor of reduced physiologic function during exercise (P < 0.05). These results demonstrate that individuals with ID present exercise intolerance potentially related to lower HRpeak and impairments in ventilatory function, and these results also suggest the possibility of peripheral muscle hypoperfusion. Existing physical activity guidelines likely underestimate the actual intensity of activity performed by individuals with ID and need to be adapted.

Do individuals with intellectual disability have a lower peak heart rate and maximal oxygen uptake?

Individuals with intellectual disability (ID) have very low physical activity and low peak oxygen uptake (VO2peak ), potentially explained by physiologically lower peak heart rates (HRpeak ). The present authors performed a retrospective analysis of a large data set of individuals with intellectual disability (n=100), with Down syndrome (DS) (n=48) and without intellectual disability (n=224) using multiple linear regression analyses, to determine if individuals with intellectual disability exhibit lower HRpeak and VO2peak than individuals without intellectual disability, controlling for age, sex and body mass index (BMI). Individuals with intellectual disability on average have significantly lower HRpeak and VO2peak than individuals without intellectual disability, even when controlling VO2peak for the lower HRpeak . This study suggests potential physiological differences in individuals with intellectual disability and warrants further investigation to determine their relevance to physical activity promotion and exercise testing in individuals with intellectual disability.

Comparison of 1- Versus 3-Minute Stage Duration During Arm Ergometry in Individuals With Spinal Cord Injury

ObjectiveTo investigate the effect of stage duration on peak physiological response to arm ergometry incremental exercise testing in individuals with spinal cord injury or disease (SCI/D) in support of developing a more individualized approach to testing. DesignParallel reliability study. SettingUniversity research laboratory. ParticipantsIndividuals with SCI/D (N=38) performed 2 peak oxygen consumption assessments comprised of 1-minute or 3-minute stages on 1 day. InterventionsNot applicable. Main Outcome MeasuresHeart rate and oxygen consumption were recorded continuously from baseline through recovery. Every 1 minute or 3 minutes, resistance increased at an individualized level, and participants continued until volitional fatigue. The highest 30-second average was selected as peak oxygen consumption (Vo2peak) and peak heart rate. The highest workload achieved for ≥30 seconds was recorded as peak power output (PO). ResultsIntraclass correlation coefficients (ICCs) were >.95 for the following variables: absolute Vo2peak (mean ± SD, 1min: 1.2±0.7, 3min: 1.2±.62L/min; 95% CI, .91–.98), relative Vo2peak (mean ± SD, 1min: 16.6±9.4, 3min: 15.8±8.0mL/kg/min; 95% CI, .90–.98), absolute peak PO (mean ± SD, 1min: 61±41, 3min: 66±41W; 95% CI, .92–.98), and relative peak PO (mean ± SD, 1min: .80±56, 3min: .90±.55W/kg; 95% CI, .91–.98). There was no significant difference in peak heart rate between 3 minutes (132±27 beats per minute [bpm]) and 1 minute (130±28 bpm); however, the ICC lower limit was <.75 (0.67–0.90). Total test time was significantly longer in the 3-minute (8:17±2:52min:s) than in the 1-minute (6:29±2:21min:s) protocol. ConclusionsFor measuring peak physiological values in an incremental arm ergometry test, stage duration is of little consequence because similar values were obtained for the main outcome measures in both protocols.

The value of cardiopulmonary exercise testing in individuals with apparently asymptomatic severe aortic stenosis: A pilot study

Risk stratification in asymptomatic patients with severe aortic stenosis (AS) is based on exercise test results. However, differentiating between pathological and physiological breathlessness during exercise is sometimes challenging. Cardiopulmonary exercise testing (CPET) may improve quantification of cardiopulmonary exercise capacity in patients with valve diseases. To assess the ability of CPET to detect abnormal responses to exercise and a clinical endpoint (occurrence of European Society of Cardiology guidelines surgical class I triggers). Forty-three consecutive patients (mean age 69±13 years; 31 men) with no reported symptoms and severe AS (aortic valve surface area<1 cm2 or indexed aortic valve surface area ≤0.6 cm2/m2) prospectively underwent symptom-limited CPET. Twelve (28%) patients had an abnormal exercise test (AET) with symptoms (abnormal dyspnoea n=11; angina n=1). Both VE/VCO2 slope>34 (hazard ratio [HR]=5.76, 95% confidence interval [CI] 1.086-30.587; P=0.04) and peak VO2≤14 mL/kg/min (HR 6.01, 95% CI 1.153-31.275; P=0.03) were independently associated with an AET. Furthermore, VE/VCO2 slope>34 (HR 3.681, 95% CI 1.318-10.286; P=0.013) and peak VO2≤14 mL/kg/min (HR 3.058, 95% CI 1.074-8.713; P=0.036) were independent predictors of reaching the clinical endpoint. Cardiopulmonary exercise testing is a useful tool for characterizing breathlessness during an exercise test in apparently asymptomatic patients with AS. Peak VO2≤14 mL/kg/min and VE/VCO2 slope>34 were associated with an AET and the occurrence of European Society of Cardiology guideline surgical class I triggers.

Cardiorespiratory Response to Exercise Testing in Individuals With Alzheimer's Disease

Billinger SA, Vidoni ED, Honea RA, Burns JM. Cardiorespiratory response to exercise testing in individuals with Alzheimer's disease. Objective To examine exercise testing response in Alzheimer's disease (AD) and possible disease-related change over time. Design Retrospective assessment of a 2-year observational study. Setting University medical center. Participants Individuals without dementia (n=50) and with AD (n=31). Interventions Not applicable. Main Outcome Measures Participants underwent a clinical dementia evaluation and performed an incremental exercise test using a treadmill and the modified Bruce protocol at baseline and at a 2-year follow-up. We examined oxygen consumption, minute ventilation, heart rate, and ventilatory equivalents for oxygen and carbon dioxide at submaximal and peak exercise intensities to determine whether the measures were different between groups or over time. Results Participants with AD and those without dementia performed similarly at submaximal effort, and both groups showed similar changes in exercise response over 2 years. However, nondemented individuals had consistently higher values of oxygen consumption ( P≤.02) and minute ventilation at peak effort at baseline ( P=.003). Conclusions Individuals with AD demonstrate physiologic responses to submaximal exercise effort that are not significantly different than individuals without dementia. However, differences are apparent at the extreme of effort.

Exercise Testing in Individuals with Morbid Obesity

Obesity is an independent risk factor for cardiovascular disease, especially in its morbid form. Bariatric surgery is an effective therapeutic option for sustained weight loss. However, there is no consensus in these cases regarding the performance of functional tests for preoperative evaluations. The aim of the present study was to analyze clinical, electrocardiographic, and hemodynamic response variables using a conventional exercise test on individuals with morbid obesity in comparison to overweight individuals. Six hundred seventeen cases were included. Group I had 290 patients with morbid obesity and group II had 327 overweight patients. All were submitted to a conventional treadmill exercise test. Classic positivity criteria were used. Both groups tolerated the test well. There was no statistically significant difference in terms of positivity of the test [ST segment abnormality or angor (P = 0.3863) or ST segment abnormality alone (P = 0.1000)]. The significantly higher values in the obese individuals were basal heart rate, basal systolic arterial pressure (SAP), maximum SAP, basal diastolic arterial pressure (DAP), maximum DAP, chronotropic deficit (P < 0.0001), and maximum rate-pressure product (P < 0.0421). The significantly lower values in the obese individuals were exercise time, maximum heart rate, and metabolic equivalents values (P < 0.0001). Hemodynamic parameters were significantly different between the two groups. However, there were no differences in terms of ST segment abnormalities or effort-induced angina. The very low functional capacity and complex arrhythmia found in some obese individuals draws attention to the need for complementary investigation with the aim of diminishing the risk of postoperative heart complications.

Reliability of Graded Exercise Testing after Traumatic Brain Injury

To assess the reliability of the submaximal and peak responses to a treadmill graded exercise test in individuals recovering from traumatic brain injury. A total of 15 individuals (11 men, 4 women; 28.5 +/- 9.2 yrs) with moderate to severe traumatic brain injury admitted into a postacute residential treatment center 10 +/- 7 mos after injury performed two treadmill graded exercise tests separated by 4-8 days. Heart rate, oxygen consumption (in milliliters per minute per kilogram), minute ventilation (in liters per minute), and respiratory exchange ratio (carbon dioxide output/oxygen consumption) were continuously monitored at 1-min intervals. Submaximal and peak values were analyzed for absolute level of agreement using the intraclass correlation coefficient. The submaximal intraclass correlation coefficient values for all variables between minutes 3 and 7 ranged from 0.80 to 0.93. Submaximal intraclass correlation coefficients before and in the subsequent minutes were less than optimal for heart rate and minute ventilation. Lower intensity workloads elicited slightly better agreement than higher intensity workloads. The peak response intraclass correlation coefficients ranged from 0.77 (heart rate) to 0.92 (oxygen consumption). Despite the presence of other co-morbidities, subjects recovering from traumatic brain injury provided consistent individual responses, allowing for reliable assessments of cardiorespiratory conditioning programs. Assessments of ambulatory efficiency, endurance, and aerobic fitness adaptations as a result of treatment for persons with traumatic brain injury should include analyses of submaximal responses to graded exercise.

Decreased peak arteriovenous oxygen difference during treadmill exercise testing in individuals infected with the human immunodeficiency virus

Cade WT, Fantry LE, Nabar SR, Keyser RE. Decreased peak arteriovenous oxygen difference during treadmill exercise testing in individuals infected with the human immunodeficiency virus. Arch Phys Med Rehabil 2003;84:1595–603. Objective To determine if arteriovenous oxygen difference was lower in asymptomatic individuals with human immunodeficiency virus (HIV) infection than in sedentary but otherwise healthy controls. Design Quasi-experimental cross-sectional. Setting Clinical exercise laboratory. Participants Fifteen subjects (10 men, 5 women) with HIV and 15 healthy gender- and activity level-matched controls (total N=30). Intervention Participants performed an incremental maximal exercise treadmill test to exhaustion. Electrocardiogram, metabolic, and noninvasive cardiac output measurements were evaluated at rest and throughout the tests. Data were analyzed by using analysis of covariance. Main outcome measures Peak oxygen consumption (V o 2), cardiac output, stroke volume, and arteriovenous oxygen difference. The arteriovenous oxygen difference was determined indirectly using the Fick equation. Results Peak V o 2 was significantly lower ( P<.0005) in participants with HIV (24.6±1.2mL·kg −1·min −1) compared with controls (32.0±1.2mL·kg −1·min −1). There were no significant intergroup differences in cardiac output or stroke volume at peak exercise. Peak arteriovenous oxygen difference was significantly lower ( P<.04) in those infected with HIV (10.8±0.5 volume %) than in controls (12.4±0.5 volume %). Conclusion The observed deficit in aerobic capacity in the participants with HIV appeared to be the result of a peripheral tissue oxygen extraction or utilization limitation. In addition to deconditioning, potential mechanisms for this significant attenuation may include HIV infection and inflammation, highly active antiretroviral therapy medication regimens, or a combination of these factors.