The Effect of Breathing Retraining Using Metronome-Based Acoustic Feedback on Exercise Endurance in COPD: A Randomized Trial.

BACKGROUND: During exercise-training patients with chronic obstructive pulmonary disease (COPD) can entrain their breathing pattern to visual-feedback cues as to achieve a slower respiratory rate and prolong exhalation. The result is an improvement in exercise tolerance and a reduction in dynamic hyperinflation. Acoustic stimuli, including metronome-generated acoustic stimuli, can entrain human movements. Accordingly, we hypothesized that exercise duration and dynamic hyperinflation would be less after exercise-training plus breathing-retraining using a metronome-based acoustic-feedback system than after exercise-training alone. METHODS: Of 205 patients with COPD [FEV1 = 44 ± 16% predicted (± SD)] recruited, 119 were randomly assigned to exercise-training plus breathing-retraining using acoustic feedback (n = 58) or exercise-training alone (n = 61). Patients exercised on a treadmill thrice-weekly for 12 weeks. Before and at completion of training, patients underwent constant-load treadmill testing with inspiratory capacity measures every 2 min. RESULTS: At completion of training, improvements in exercise duration in the breathing-retraining plus exercise-training and exercise-training alone groups were similar (p = 0.35). At isotime, inspiratory capacity increased (less exercise-induced dynamic hyperinflation) by 3% (p = 0.001) in the breathing-retraining plus exercise-training group and remained unchanged in the exercise-alone group. The between-group change in inspiratory capacity, however, was not significant (p = 0.08). CONCLUSIONS: In patients with COPD, breathing-retraining using a metronome-based acoustic feedback did not result in improved exercise endurance or decreased dynamic hyperinflation when compared to exercise-training alone. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT NCT01009099; URL: http://www.clinicaltrials.gov.

Randomized Controlled Trial of Physical Exercise in Diabetic Veterans With Length-Dependent Distal Symmetric Polyneuropathy.

Rationale: Physical exercise is an essential adjunct to the management of patients with type 2 diabetes mellitus. Therapeutic interventions that improve blood flow to peripheral nerves, such as exercise, may slow the progression of neuropathy in the diabetic patient. Aims: This randomized clinical trial was conducted to determine whether a structured program of aerobic, isokinetic strength, or the combination of aerobic-isokinetic strength exercise intervention alters peripheral nerve function in glycemic-controlled diabetic patients with advanced length-dependent distal symmetric polyneuropathy. Methods: Forty-five patients with type 2 diabetes mellitus exhibiting tight glycemic control (HbA1c intergroup range 7.2-8.0%) were randomized by block design across four experimental groups: sedentary controls (n = 12), aerobic exercise (n = 11), isokinetic strength (n = 11), or the combination of aerobic-isokinetic strength training (n = 11). Patients randomized to training groups exercised 3× per week for 12 weeks, whereas patients randomized to the sedentary control group received standard of care. To minimize attention and educational bias, all patients attended a 12-session health promotion educational series. At baseline, immediately following intervention, and again at 12-week post-intervention, detailed nerve conduction studies were conducted as a primary outcome measure. At these same intervals, all patients completed as secondary measures quantitative sensory testing, symptom-limited treadmill stress tests, and a Short-Form 36-Veterans Questionnaire (SF-36V). Results: Of the 45 patients randomized into this study, 37 (82%) had absent sural nerve responses, 19 (42%) had absent median sensory nerve responses, and 17 (38%) had absent ulnar sensory nerve responses. By comparison, responses from tibial nerves were absent in only three (7%) subjects while responses from peroneal nerves were absent in five (11%) subjects. Eleven (92%) of 12 patients that had volunteered to be biopsied exhibited abnormal levels of epidermal nerve fiber densities. Exercise, regardless of type, did not alter sensory or motor nerve electrodiagnostic findings among those patients exhibiting measurable responses (ANOVA). There was, however, a modest (p = 0.01) beneficial effect of exercise on sensory nerve function (Fisher's Exact Test). Importantly, the beneficial effect of exercise on sensory nerve function was enhanced (p = 0.03) during the post-intervention interval. In addition, three of six patients that had undergone exercise intervention exhibited a marked 1.9 ± 0.3-fold improvement in epidermal nerve fiber density. By comparison, none of three sedentary patients whom agreed to be biopsied a second time showed improvement in epidermal nerve fiber density. Compared to baseline values within groups, and compared with sedentary values across groups, neither aerobic, isokinetic strength, or the combination of aerobic-isokinetic strength exercise intervention altered peak oxygen uptake. Patients that underwent aerobic or the combined aerobic-isokinetic strength exercise intervention, however, demonstrated an increase in treadmill test duration that was sustained over the 12-week post-intervention period. Conclusion: A 12-week course of physical exercise, regardless of type, does not alter sensory or motor nerve electrodiagnostic findings. In a subset of patients, a short-term structured program of aerobic exercise may selectively improve sensory nerve fiber function. Large-scale exercise lifestyle intervention trials are warranted to further evaluate the impact of aerobic exercise on sensory nerve fiber function in diabetic neuropathic patients. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT00955201.

Structured Exercise in Obese Diabetic Patients with Chronic Kidney Disease: A Randomized Controlled Trial.

BACKGROUND: Patients with type 2 diabetes mellitus (DM), obesity, and chronic kidney disease (CKD) are generally physically inactive and may benefit from exercise. Our objective was to determine the effects of structured exercise on physical fitness, kidney function, endothelial function, inflammation, and body composition in such patients. METHODS: In this randomized, controlled trial, 36 male patients (age 49-81) were randomly assigned to exercise + diet management (n = 18) or diet alone (n = 18). Participants were eligible if they had type 2 DM, body mass index >30 kg/m2, CKD stages 2-4, and persistent proteinuria (>200 mg/g creatinine for >3 months). The exercise intervention was a 12-week (3 days per week) program of aerobic and resistance training followed by 40 weeks of home exercise. The primary outcome measure was change from baseline in urine protein to creatinine ratio (UPCR) at 12 and 52 weeks. RESULTS: Thirty-two participants completed the study (14 exercise + diet, 18 diet-alone group). The change from baseline in UPCR was slightly greater in the diet-alone group at 12 weeks but not at 52 weeks. Changes in both symptom-limited and constant-workrate treadmill times were significantly higher in the exercise + diet group at 12 weeks but not at 52 weeks. There were no significant differences in urine albumin to creatinine ratio, estimated glomerular filtration rate, endothelial function, inflammation, or body composition between the groups. CONCLUSIONS: In obese diabetic subjects with CKD, structured exercise improved exercise capacity but not body composition or renal function. This is a work of the US Government and is not subject to copyright protection in the USA. Foreign copyrights may apply. Published by S. Karger AG, Basel.

Contrasting breathing retraining and helium-oxygen during pulmonary rehabilitation in COPD: a randomized clinical trial.

BACKGROUND: Breathing-retraining and helium-oxygen (heliox) have been used to improve exercise tolerance in COPD. We hypothesized that, in patients with COPD, exercise duration after exercise-training plus breathing-retraining and oxygen would be longer than after exercise-training plus heliox or after exercise-training plus oxygen alone. We also explored the short-term maintenance of gains in exercise duration after using each technique. METHODS: Of 192 COPD patients recruited, 103 were randomly assigned to exercise-training plus heliox (n = 33), exercise-training plus breathing-retraining and oxygen (n = 35) and exercise-training and oxygen (n = 35). FiO2 was 0.30 during testing and training in all groups. Patients exercised on a treadmill thrice-weekly for eight weeks. Before, at completion of training, and six-weeks later, patients underwent constant-load treadmill testing. RESULTS: At completion of training, improvements in exercise duration in the heliox and breathing-retraining groups were not significantly different. Compared to the exercise-training plus oxygen group, exercise duration improved more in the breathing-retraining group (P = 0.008) but not in the heliox group (P = 0.142). Hyperinflation was reduced with breathing-retraining plus oxygen compared to the other two groups. Six-weeks later, improvements in exercise duration were still greater with breathing-retraining than with exercise-training (P = 0.015). In contrast, improvements in exercise duration with heliox did not differ from those in the other two groups. CONCLUSIONS: In moderate-to-severe COPD, exercise-training combined with either heliox or with breathing-retraining yielded not significantly different improvements in exercise duration - with only the latter being superior to exercise-training. Six-weeks after training, these improvements were still greater after exercise-training plus breathing-retraining than after exercise-training. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00123422.

The effects of smoking status on walking ability and health-related quality of life in patients with peripheral arterial disease.

BACKGROUND: Smoking is a leading risk factor for peripheral arterial disease (PAD), yet little is known about the interrelationships among smoking status, walking endurance, calf muscle tissue oxygenation, and quality of life in patients with PAD. OBJECTIVE: The aim of this study was to explore the differences in factors associated with walking endurance including walk distance, perceived walking ability, measures of skeletal muscle tissue oxygenation (StO2), claudication pain, peak oxygen consumption per unit time, and quality of life in smokers versus nonsmokers. METHODS: A total of 105 patients with PAD performed progressive, symptom-limited treadmill test. Ankle-brachial index was measured at baseline. Calf muscle tissue oxygenation measures were obtained during testing. The RAND Short Form-36 and Walking Impairment Questionnaire were used to measure health-related quality of life (HR-QoL). RESULTS: In the total sample (36 current smokers, 69 nonsmokers), smokers had steeper declines in StO2 from baseline to 2 minutes (42.3% vs 33%, P = .05) and shorter distance walked to onset of claudication pain (142.6 vs 247.7 m) than did nonsmokers (P < .0125), despite having no differences in ankle-brachial index, peak oxygen consumption per unit time, or any momentary measure of StO2 during walking. Smokers reported significantly lower HR-QoL on the Short Form-36 in several domains but no differences in the Walking Impairment Questionnaire measures. The smokers were younger than the nonsmokers; however, when age was entered as a covariate in the analyses, the results remained unchanged. CONCLUSIONS: These findings suggest that smokers have lower HR-QoL than do nonsmokers with PAD and that smoking confers risks for disrupted tissue oxygenation above those seen in patients who do not smoke.

The Effects of Walking or Walking-with-Poles Training on Tissue Oxygenation in Patients with Peripheral Arterial Disease.

This randomized trial proposed to determine if there were differences in calf muscle StO(2) parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program. Data were collected on 85 patients who were randomized to a traditional walking program (n = 40) or walking-with-poles program (n = 45) of exercise training. Patients walked for 3 times weekly for 12 weeks. Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests (n = 36 traditional walking and n = 35 walking-with-poles). Using the near-infrared spectroscopy measures, StO(2) was measured prior to, during, and after exercise. At baseline, calf muscle oxygenation decreased from 56 ± 17% prior to the treadmill test to 16 ± 18% at peak exercise. The time elapsed prior to reaching nadir StO(2) values increased more in the traditional walking group when compared to the walking-with-poles group. Likewise, absolute walking time increased more in the traditional walking group than in the walking-with-poles group. Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program. In conclusion, the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD.

Comparison of walking with poles and traditional walking for peripheral arterial disease rehabilitation.

PURPOSE: The purpose of this study was to compare the effects of a 24-week walking with poles rehabilitation program with a traditional 24-week walking program on physical function in patients with peripheral arterial disease (PAD). METHODS: Patients with PAD (n = 103, age = 69.7 ± 8.9 years, ankle-brachial index < 0.90 or evidence of calcified vessels) were randomized into a rehabilitation program of traditional walking (n = 52) or walking with poles (n = 51). Patients exercised 3 times per week for 24 weeks. Exercise endurance was measured by time walked on a constant work rate treadmill test at 6, 12, and 24 weeks. Perceived physical function was measured by the Medical Outcomes Study Short Form-36 and Walking Impairment Questionnaire. Tissue oxygenation was measured using near-infrared spectroscopy. RESULTS: Patients assigned to the traditional walking group walked longer at 24 weeks than those assigned to the pole walking group (21.10 ± 17.07 minutes and 15.02 ± 12.32 minutes, respectively, P = .037). There were no differences between the groups in tissue oxygenation. However, there was a significant lengthening of time for which it took to reach minimum tissue oxygenation values (P < .001) within the groups on the constant work rate test. There were no differences between the groups in perceived physical function as measured by the Physical Function subscale on the Medical Outcomes Study Short Form-36 or perceived walking distance as measured by the Walking Distance subscale on the Walking Impairment Scale. CONCLUSIONS: Traditional walking was superior to walking with poles in increasing walking endurance on a constant work rate treadmill test for patients with PAD.

Design, development and validation of the RedBrick Health Assessment: a questionnaire-based study.

OBJECTIVES: Health risk assessment (HRA) questionnaires have become a popular tool to help quantify health issues within populations. Over the last decade HRAs have increasingly been delivered in the online environment. The objective of this study was to create and validate an HRA that is optimized for delivery via the Internet. DESIGN: After an iterative process of user testing and interface design the RedBrick Health Assessment (RBHA) was validated against known domain specific questionnaires with 464 working Americans, and with medical claims data from over 25,000 employees. SETTING: All consumer testing, data capture and analysis occurred at the offices of RedBrick Health Corporation, Minneapolis, USA and via a secure online portal. PARTICIPANTS: Individuals in full-time employment in the USA, who were between 18 and 65 years of age at the time inquiry. MAIN OUTCOME MEASURES: Correlation of the included RBHA domains with the output from known gold standard health question sets for each assessed health domain. RESULTS: The iterative development process employed in creating the RBHA produced a tool that had a high degree of user acceptability. The domains demonstrated good correlations with relevant gold standard questionnaire measures, good internal consistency, and acceptable sensitivity and specificity when compared to gold standard risk stratification and high-risk classification (specificity of domains ranged from 76-94%). A test-retest correlation co-efficient of 0.7, or greater, was achieved 8 weeks after initial completion. CONCLUSIONS: The RBHA is a new breed of HRA that has been specifically developed for capturing health status information in an online environment. At its heart is user centricity and this focus has enabled the creation of a tool that is not only highly engaging but also captures accurate and robust health status information.

Energy cost of physical activities in persons with spinal cord injury.

INTRODUCTION: The objectives of this descriptive study were (a) to determine the energy expenditure of activities commonly performed by individuals with a spinal cord injury (SCI) and summarize this information and (b) to measure resting energy expenditure and establish the value of 1 MET for individuals with SCI. METHODS: One-hundred seventy adults with SCI were partitioned by gender, anatomical level of SCI, and American Spinal Injury Association designations for motor function. Twenty-seven physical activities, 12 recreational/sport and 15 daily living, were performed, while energy expenditure was measured continuously via a COSMED K4b portable metabolic system. In addition, 66 adult males with SCI completed 30 min of supine resting energy testing in a quiet environment. RESULTS: Results for the 27 measured activities are reported in kilocalories per minute (kcal·min(-1)) and VO2 (mL·min(-1) and mL·kg(-1)·min(-1)). One MET for a person with SCI should be adjusted using 2.7 mL·kg(-1)·min(-1). Using 2.7 mL·kg(-1)·min(-1), the MET range for persons in the motor incomplete SCI group was 1.17 (supported standing) to 6.22 (wheeling on grass), and 2.26 (billiards) to 16.25 (hand cycling) for activities of daily living and fitness/recreation, respectively. The MET range for activities of daily living for persons in the group with motor complete SCI was 1.27 (dusting) to 4.96 (wheeling on grass) and 1.47 (bait casting) to 7.74 (basketball game) for fitness/recreation. CONCLUSIONS: The foundation for a compendium of energy expenditure for physical activities for persons with SCI has been created with the completion of this study. In the future, others will update and expand the content of this compendium as has been the case with the original compendium for the able-bodied.

Physical Activity Inventory for Patients with Spinal Cord Injury.

OBJECTIVES: To test the reliability and validity of a physical activity instrument adapted for individuals with spinal cord injuries (SCI), the Physical Activity Instrument-SCI (PAI-SCI). METHODS: Eligible participants completed the adapted PAI-SCI questionnaire at baseline and 1 week later. At baseline, they were also given an Actical accelerometer to wear on their wrist for 1 week. RESULTS: Forty-three male subjects completed the study. There was a moderate relationship between total score on the PAI-SCI and total activity count determined by accelerometry (r = 0.42, P = 0.036). The PAI-SCI was able to differentiate between people with upper and lower level injuries (P = 0.05). Test-retest reliability was supported for the exercise and the general activity/self care subscales and not supported for the light household or the outdoor/gardening subscales. CONCLUSION: The PAI-SCI was able to distinguish between physical activity amongst those with upper level and lower level injuries. More research is needed before the PAI-SCI can be recommended for use in clinical trials.