Exercise training and peripheral vascular disease

Changes in miRNA expression in patients with peripheral arterial vascular disease during moderate- and vigorous-intensity physical activity

BACKGROUND

Walking is the preferred therapy for peripheral arterial disease in early stage. An effect of walking exercise is the increase of blood flow and fluid shear stress, leading, triggered by arteriogenesis, to the formation of collateral blood vessels. Circulating micro-RNA may act as an important information transmitter in this process. We investigated the acute effects of a single bout of 1) aerobic walking with moderate intensity; and 2) anaerobic walking with vigorous intensity on miRNA parameters related to vascular collateral formation.

METHODS

Ten (10) patients with peripheral arterial disease with claudication (age 72 ± 7 years) participated in this two-armed, randomized-balanced cross-over study. The intervention arms were single bouts of supervised walking training at (1) vigorous intensity on a treadmill up to volitional exhaustion and (2) moderate intensity with individual selected speed for a duration of 20 min. One week of washout was maintained between the arms. During each intervention, heart rate was continuously monitored. Acute effects on circulating miRNAs and lactate concentration were determined using pre- and post-intervention measurement comparisons.

RESULTS

Vigorous-intensity walking resulted in a higher heart rate (125 ± 21 bpm) than the moderate-intensity intervention (88 ± 9 bpm) (p < 0.05). Lactate concentration was increased after vigorous-intensity walking (p = 0.005; 3.3 ± 1.2 mmol/l), but not after moderate exercising (p > 0.05; 1.7 ± 0.6 mmol/l). The circulating levels of miR-142-5p and miR-424-5p were up-regulated after moderate-intensity (p < 0.05), but not after vigorous-intensity training (p > 0.05).

CONCLUSION

Moderate-intensity walking seems to be more feasible than vigorous exercises to induce changes of blood flow and endurance training-related miRNAs in patients with peripheral arterial disease. Our data thus indicates that effect mechanisms might follow an optimal rather than a maximal dose response relation. Steady state walking without the necessity to reach exhaustion seems to be better suited as stimulus.

Exercise and Peripheral Arteriosclerosis

Adaptation of a healthy lifestyle including adequate daily physical activity is shown to reduce 80% of cardiovascular mortality and 40% of cancer-related deaths. A large body of evidence exists proving that this relationship is dose dependent, and even half of the recommended normal physical activity yields significant risk reduction. There has been no medical therapy that would provide such high percentages of reduction in mortality to date. The World Health Organization, therefore, has started an initiative to implement exercise into daily life as a primary prevention measure. Herein, we will focus on the effects of exercise on the vasculature, mainly the peripheral vasculature, in the context of atherosclerotic disease. Exercise has a fundamental role in the pathogenesis, diagnosis, and treatment of atherosclerotic vascular disease. It exerts a protective effect against the development of atherosclerosis irrespective of other cardiovascular risk factors. Additionally, exercise induces changes in vascular hemodynamics helping us to elucidate the presence of obscure vascular involvement. Once again, exercise is the main treatment modality in peripheral arterial disease with accumulating evidence to reduce symptoms and improve both exercise capacity and cardiovascular symptoms.

All Patients Benefit Equally From a Supervised Exercise Program for Claudication

This study assessed the effect of gender, diabetic status, statin use, smoking, hypertension, cardiac status, and use of cilostazol on the outcome of a supervised exercise program for patients with claudication. Patient risk factors were prospectively recorded in a group of patients who had completed 1 year on a supervised exercise program. In 165 claudicant patients, maximum walking distance increased ( P < .0001) from 67 meters (range, 17-196) to 122 meters (range, 43-409). Quality of life as measured by the Medical Outcome Study Short Form 36 increased ( P < .0001) from a median of 78 (range, 55-110) to 99 (range, 71-154). The improvements in claudication distance, maximal walking distance, and quality of life after the exercise program were not dependent on any of the measured patient factors. Patients referred to exercise programs for claudication are a heterogenous group. Despite this, they benefit equally from such a program.

Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases

This review provides the reader with the up-to-date evidence-based basis for prescribing exercise as medicine in the treatment of 26 different diseases: psychiatric diseases (depression, anxiety, stress, schizophrenia); neurological diseases (dementia, Parkinson's disease, multiple sclerosis); metabolic diseases (obesity, hyperlipidemia, metabolic syndrome, polycystic ovarian syndrome, type 2 diabetes, type 1 diabetes); cardiovascular diseases (hypertension, coronary heart disease, heart failure, cerebral apoplexy, and claudication intermittent); pulmonary diseases (chronic obstructive pulmonary disease, asthma, cystic fibrosis); musculo-skeletal disorders (osteoarthritis, osteoporosis, back pain, rheumatoid arthritis); and cancer. The effect of exercise therapy on disease pathogenesis and symptoms are given and the possible mechanisms of action are discussed. We have interpreted the scientific literature and for each disease, we provide the reader with our best advice regarding the optimal type and dose for prescription of exercise.

Effects of 12-week supervised treadmill training on spatio-temporal gait parameters in patients with claudication

The purpose of the study was to evaluate selected temporal and spatial gait parameters in patients with intermittent claudication after completion of 12-week supervised treadmill walking training. The study included 36 patients (26 males and 10 females) aged: mean 64 (SD 7.7) with intermittent claudication. All patients were tested on treadmill (Gait Trainer, Biodex). Before the programme and after its completion, the following gait biomechanical parameters were tested: step length (cm), step cycle (cycle/s), leg support time (%), coefficient of step variation (%) as well as pain-free walking time (PFWT) and maximal walking time (MWT) were measured. Training was conducted in accordance with the current TASC II guidelines. After 12 weeks of training, patients showed significant change in gait biomechanics consisting in decreased frequency of step cycle (p < 0.05) and extended step length (p < 0.05). PFWT increased by 96% (p < 0.05). MWT increased by 100% (p < 0.05). After completing the training, patients' gait was more regular, which was expressed via statistically significant decrease of coefficient of variation (p < 0.05) for both legs. No statistically significant relation between the post-training improvement of PFWT and MWT and step length increase and decreased frequency of step cycle was observed (p > 0.05).

IMPLICATIONS FOR REHABILITATION

Twelve-week treadmill walking training programme may lead to significant improvement of temporal and spatial gait parameters in patients with intermittent claudication. Twelve-week treadmill walking training programme may lead to significant improvement of pain-free walking time and maximum walking time in patients with intermittent claudication.

Managing comorbidities in COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Age and smoking are common risk factors for COPD and other illnesses, often leading COPD patients to demonstrate multiple coexisting comorbidities. COPD exacerbations and comorbidities contribute to the overall severity in individual patients. Clinical trials investigating the treatment of COPD routinely exclude patients with multiple comorbidities or advanced age. Clinical practice guidelines for a specific disease do not usually address comorbidities in their recommendations. However, the management and the medical intervention in COPD patients with comorbidities need a holistic approach that is not clearly established worldwide. This holistic approach should include the specific burden of each comorbidity in the COPD severity classification scale. Further, the pharmacological and nonpharmacological management should also include optimal interventions and risk factor modifications simultaneously for all diseases. All health care specialists in COPD management need to work together with professionals specialized in the management of the other major chronic diseases in order to provide a multidisciplinary approach to COPD patients with multiple diseases. In this review, we focus on the major comorbidities that affect COPD patients. We present an overview of the problems faced, the reasons and risk factors for the most commonly encountered comorbidities, and the burden on health care costs. We also provide a rationale for approaching the therapeutic options of the COPD patient afflicted by comorbidity.

An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation

BACKGROUND

Pulmonary rehabilitation is recognized as a core component of the management of individuals with chronic respiratory disease. Since the 2006 American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement on Pulmonary Rehabilitation, there has been considerable growth in our knowledge of its efficacy and scope.

PURPOSE

The purpose of this Statement is to update the 2006 document, including a new definition of pulmonary rehabilitation and highlighting key concepts and major advances in the field.

METHODS

A multidisciplinary committee of experts representing the ATS Pulmonary Rehabilitation Assembly and the ERS Scientific Group 01.02, "Rehabilitation and Chronic Care," determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant clinical and scientific expertise. The final content of this Statement was agreed on by all members.

RESULTS

An updated definition of pulmonary rehabilitation is proposed. New data are presented on the science and application of pulmonary rehabilitation, including its effectiveness in acutely ill individuals with chronic obstructive pulmonary disease, and in individuals with other chronic respiratory diseases. The important role of pulmonary rehabilitation in chronic disease management is highlighted. In addition, the role of health behavior change in optimizing and maintaining benefits is discussed.

CONCLUSIONS

The considerable growth in the science and application of pulmonary rehabilitation since 2006 adds further support for its efficacy in a wide range of individuals with chronic respiratory disease.

Near-infrared spectroscopy assessment following exercise training in patients with intermittent claudication and in untrained healthy participants

Selected near-infrared spectroscopy (NIRS) parameters were assessed in healthy untrained participants and in peripheral arterial disease (PAD) trained patients to evaluate their usefulness in rehabilitative outcome. Forty-five PAD and 15 healthy participants were studied at entry and at 34 ± 2 weeks. Healthy participants performed their usual activities. Patients with PAD performed 2 home-based programs: structured at prescribed pace (S-pre, n = 31) and unstructured at free pace (U-free, n = 14). We measured ankle-brachial index (ABI), NIRS calf oxygen consumption at rest, NIRS dynamic muscle perfusion during an incremental test, and walking capacity. In all patients with PAD the NIRS parameters significantly increased approaching the stable values of untrained healthy participants. Among PAD, only S-pre group showed significant improvements in hemodynamic, functional, and NIRS parameters with selective adaptations in the worse legs. The assessment of NIRS parameters, that were found stable without training in healthy and modified in PAD only following structured training, might outline the local exercise-induced adaptations.

Limb-specific and cross-transfer effects of arm-crank exercise training in patients with symptomatic peripheral arterial disease

Arm cranking is a useful alternative exercise modality for improving walking performance in patients with intermittent claudication; however, the mechanisms of such an improvement are poorly understood. The main aim of the present study was to investigate the effects of arm-crank exercise training on lower-limb O2 delivery in patients with intermittent claudication. A total of 57 patients with intermittent claudication (age, 70±8 years; mean±S.D.) were randomized to an arm-crank exercise group or a non-exercise control group. The exercise group trained twice weekly for 12 weeks. At baseline and 12 weeks, patients completed incremental tests to maximum exercise tolerance on both an arm-crank ergometer and a treadmill. Respiratory variables were measured breath-by-breath to determine peak V̇O2 (O2 uptake) and ventilatory threshold. Near-IR spectroscopy was used in the treadmill test to determine changes in calf muscle StO2 (tissue O2 saturation). Patients also completed a square-wave treadmill-walking protocol to determine V̇O2 kinetics. A total of 51 patients completed the study. In the exercise group, higher maximum walking distances (from 496±250 to 661±324 m) and peak V̇O2 values (from 17.2±2.7 to 18.2±3.4 ml·kg−1 of body mass·min−1) were recorded in the incremental treadmill test (P<0.05). After training, there was also an increase in time to minimum StO2 (from 268±305 s to 410±366 s), a speeding of V̇O2 kinetics (from 44.7±10.4 to 41.3±14.4 s) and an increase in submaximal StO2 during treadmill walking (P<0.05). There were no significant changes in the control group. The results suggest that the improvement in walking performance after arm-crank exercise training in patients with intermittent claudication is attributable, at least in part, to improved lower-limb O2 delivery.

Risk factor profiles and use of cardiovascular drug prevention in women and men with peripheral arterial disease

OBJECTIVE

To determine cardiovascular comorbidities and use of cardiovascular disease preventive drugs in patients with peripheral arterial disease (PAD), with special attention to sex differences.

DESIGN

A cross-sectional point-prevalence study.

PATIENTS

A population sample of patients that are 60-90 years old.

SETTING

Primary care areas in four Swedish regions.

MAIN OUTCOME MEASURES

Prevalence of PAD stages, comorbidities and medication use.

RESULTS

The prevalence of any type of PAD was 18.0% (range 16-20), of asymptomatic peripheral arterial disease (APAD) was 11.1% (range 9-13), intermittent claudication was 6.8% (range 6.5-7.1), and of critical limb ischemia (CLI) was 1.2% (range 1.0-1.5). APAD and CLI were more common in women. Statins were used by 17.5% (range 16.9-18.2), 29.4% (range 29.0-30.1), and 30.3% (range 29.9-30.8) of the patients with APAD, intermittent claudication, and CLI, respectively, and antiplatelet therapy was reported by 34.1% (range 33.7-34.3), 47.6% (range 47.3-47.9), and 60.2% (range 59.1-60.7). The odds ratio for having APAD was 1.7 (range 1.2-2.4) for women with a smoking history of 10 years in relation to nonsmokers. This association was observed only in men who had smoked for at least 30 years or more. Preventive drug use was more common in men with PAD. Compared with women they had an odds ratio of 1.3 (range 1.1-1.5) for lipid-lowering therapy, 1.3 (range 1.0-1.7) for [beta]-blockers or angiotensin-converting enzyme inhibitors, and 1.5 (range 1.2-1.9) for antiplatelet therapy.

CONCLUSION

The patients' risk factor profiles differed among the PAD stages. Smoking duration already seemed to be a risk factor for women with PAD after 10 years of smoking, as compared with 30 years for men, and fewer women reported use of preventive medication. These observations may partly explain the sex differences in prevalence that were observed.

Benefits of low-intensity pain-free treadmill exercise on functional capacity of individuals presenting with intermittent claudication due to peripheral arterial disease

Patients with intermittent claudication due to peripheral arterial disease (PAD) experience muscle aching during walking secondary to ischemia. The purpose of this study was to examine the effects of low-intensity pain-free exercise (LIPFE) on functional capacity of individuals with PAD. A total of 12 participants with PAD underwent training on treadmill for 6 weeks, twice a week, for about 45 minutes. Outcome measures included walking distance (WDI), walking duration (WDU), mean walking rate (WR), estimated oxygen consumption (EVO(2)), metabolic equivalent (MET), estimated total energy expenditure (ETEE), and estimated rate of energy expenditure (EREE). Mean improvement of WDI, WDU, and MWR were 104% (an addition of 1.0 km), 55% (an addition of 13.3 minutes), and 41% (0.9 km/h faster), respectively. Mean improvement of EVO(2), MET, ETEE, and EREE, were 20%, 20%, 80%, and 20%, respectively. In conclusion, it appears that LIPFE training is an effective intervention for individuals presenting with PAD.

Plantar flexion: an effective training for peripheral arterial disease

This study examined whether a training intervention likely to elicit adaptations in the leg could result in reduced leg pain and increased whole body physical capacity. Twenty-seven peripheral arterial disease (PAD) patients were randomized to either an individual leg plantar flexion training group (TG) training 4 x 4 min intervals at 80% of maximal work rate three times per week for 8 weeks or a control group. The TG significantly increased plantar flexion peak oxygen uptake and power output by 23.5 and 43.9%, respectively. Treadmill peak oxygen uptake (VO(2peak)) significantly increased 12.3% in the TG and was associated with a significant increased time to exhaustion of 20.0% when treadmill walking. Eleven of 14 patients no longer reported leg pain limitations at VO(2peak). No differences in cardiac output measured at VO(2peak), or walking economy were observed. Plantar flexion training was effective in increasing VO(2peak) and walking performance, and may be a useful strategy in treatment of PAD.

Physiological and functional impact of an unsupervised but supported exercise programme for claudicants

OBJECTIVES

To evaluate an unsupervised home-based exercise programme for physiological, functional, and quality of life impact in patients with symptomatic peripheral arterial disease.

DESIGN

Prospective cohort with exercise intervention.

MATERIALS

Human performance laboratory with non-invasive haemodynamic assessment facilities.

METHODS

Forty-seven patients with symptomatic peripheral arterial disease (mean age 67.6+/-7 years, 33 males) participated in an unsupervised home-based exercise programme. Heart rate (HR), ankle brachial blood pressure index (ABPI), leg blood flow (BF), and blood lactate were measured before and after a graded treadmill walk at baseline and after the 12-week exercise programme. Maximum walking distance (MWD) during the treadmill walk was measured at baseline and 12 weeks. Exercise compliance, functional parameters, and quality of life (VascuQoL) were assessed by questionnaire.

RESULTS

MWD, leg BF, and VascuQoL scores increased significantly, while resting HR, exercise HR, and end of walk rate-pressure-product (RPP) decreased significantly after 12 weeks. Exercise compliance was significantly correlated with increase in MWD (r=0.89, p<0.001) and QOL score improvement (r=0.61, p<0.001).

CONCLUSIONS

This supported but unsupervised exercise programme generated improvements in walking distance and leg blood flow without detectable increases in cardiorespiratory work. Exercise compliance is related to MWD and VascuQoL score in a dose-response manner.

Estudo comparativo da evolução e sobrevida de pacientes com claudicação intermitente, com ou sem limitação para exercícios, acompanhados em ambulatório específico

CONTEXTO: Os fatores de risco para doença aterosclerótica, que influenciam na evolução natural dessa doença, estão bem estabelecidos, assim como o benefício do programa de exercícios para pacientes claudicantes. Entretanto, faltam informações sobre a relação entres limitações clínicas e fatores de risco, com desempenho do programa de caminhadas e suas implicações na evolução e mortalidade destes pacientes. OBJETIVO: Comparar, ao longo do tempo, a distância de claudicação e sobrevida de pacientes claudicantes em ambulatório específico, com ou sem limitação para exercícios. MÉTODOS: Foi feito um estudo tipo coorte retrospectivo de 185 pacientes e 469 retornos correspondentes, no período de 1999 a 2005, avaliando-se dados demográficos, distância média de claudicação (CI) e óbito. Os dados foram analisados nos programas Epi Info, versão 3.2, e SAS, versão 8.2. RESULTADOS: A idade média foi de 60,9±11,1 anos, sendo 61,1% do sexo masculino e 38,9% do sexo feminino. Oitenta e sete por cento eram brancos, e 13%, não-brancos. Os fatores de risco associados foram: hipertensão (69,7%), tabagismo (44,3%), dislipidemia (32,4%) e diabetes (28,6%). Nos claudicantes para menos de 500 m, a CI inicial em esteira foi de 154,0±107,6 m, e a CI final, de 199,8±120,5 m. Cerca de 45% dos pacientes tinham alguma limitação clínica para realizar o programa de exercícios preconizado, como: angina (26,0%), acidente vascular cerebral (4,3%), artropatia (3,8%), amputação menor ou maior com prótese (2,1%) ou doença pulmonar obstrutiva crônica (1,6%). Cerca de 11,4% dos pacientes tinham infarto do miocárdio prévio, e 5,4% deles usavam cardiotônico. O tempo de seguimento médio foi de 16,0±14,4 meses. A distância média de CI referida pelos pacientes aumentou 100% (de 418,47 m para 817,74 m) ao longo de 2 anos, nos grupos não-limitante (p < 0,001) e não-tabagista (p < 0,001). A sobrevida dos claudicantes foi significativamente menor no grupo com limitação. A análise de regressão logística mostrou que a limitação para realização de exercícios, isoladamente, influenciou significativamente na mortalidade (p < 0,001). CONCLUSÃO: A realização correta e regular dos exercícios e o abandono do fumo melhoram a distância de claudicação, além de reduzir a mortalidade nesses casos, seja por meio de efeitos positivos próprios do exercício, seja por meio de controle dos fatores de risco e de seus efeitos adversos.

Local Versus Systemic Mechanisms Underlying Supervised Exercise Training for Intermittent Claudication

The mechanisms by which exercise training improves intermittent claudication remain unclear. In this article, the effects of local and systemic physiological factors on improved exercise tolerance after a supervised exercise program in claudicants are investigated. A total of 60 patients were randomized to 3 months of supervised exercise followed by 3 months of unsupervised exercise, or to exercise advice alone (control). Supervised exercise increased both pain-free and maximal walking distances. Heart rate during submaximal exercise and resting mean arterial pressure were lower after supervised exercise at 6 months. Serum lactate at maximum claudication increased significantly after 3 months in the supervised exercise group but this change had resolved by 6 months. Symptomatic improvement was accompanied by modest reductions in mean arterial pressure and submaximal heart rate on exercise. Increased serum lactate at maximum claudication subsequently declined despite continued improvement in walking distance, suggesting local adaptations to improve efficiency of muscle oxygen delivery and/or utilization.

Supervised Exercise Training for Intermittent Claudication: Lasting Benefit at Three Years

OBJECTIVES

To assess the long-term outcome of supervised exercise training for intermittent claudication.

METHODS

A prospective study was undertaken of all patients referred to a single centre with intermittent claudication (>46 m). Patients underwent supervised exercise training twice weekly for 10 weeks, with regular follow-up to 3 years. Actual Claudication Distance (ACD), Maximum Walking Distance (MWD) and ankle-brachial pressure indices (ABPI) were measured.

RESULTS

In 202 patients the initial median ACD and MWD were 112 m and 197 m. Following exercise therapy both the median ACD and MWD increased to 266 m and 477 m at three months, increases of 237% and 242% respectively (p<0.001). At three years the median ACD and MWD were 250 m and 372 m, increases of 223% and 188% respectively (p<0.001). There was no significant change in ACD or MWD at 3 months compared to 1, 2 or 3 years. ABPI remained unchanged throughout.

CONCLUSIONS

Supervised exercise training has long term benefit in patients with intermittent claudication. Results seen at 12 weeks are sustained at three years.

Time-courses of perfusion and phosphocreatine in rat leg during low-level exercise and recovery

PURPOSE

To develop a noninvasive protocol for measuring local perfusion and metabolic demand in muscle tissue with sufficient sensitivity and time resolution to monitor kinetics at the onset of low-level exercise and during recovery.

MATERIALS AND METHODS

Capillary-level perfusion, the critical factor that determines oxygen and substrate delivery to active muscle, was measured by an arterial spin labeling (ASL) technique optimized for skeletal muscle. Phosphocreatine (PCr) kinetics, which signal the flux of oxidative phosphorylation, were measured by (31)P MR spectroscopy. Perfusion and PCr measurements were made in parallel studies before, during, and after three different intensities of low-level, stimulated exercise in rat hind limb.

RESULTS

The data reveal close coupling between the perfusion response and PCr changes. The onset and recovery time constants for PCr changes were independent of contractile force over the range of forces studied. Perfusion time constants during both onset of exercise and recovery tended to increase with contractile force.

CONCLUSION

These results demonstrate that the protocol implemented can be useful for probing the mechanisms that control skeletal muscle blood flow, the physiological limits to muscle performance, and the causes for the attenuated exercise-induced hyperemia observed in disease states.

The role of ascorbic acid and exercise in chronic ischemia of skeletal muscle in rats

This study was designed to investigate the effects of peripheral arterial insufficiency, exercise, and vitamin C administration on muscle performance, cross-sectional area, and ultrastructural morphology in extensor digitorum longus (EDL) and soleus (Sol) muscles in rats. Adult Wistar rats were assigned to ischemia alone (isch), ischemia-exercised (exe), ischemia-vitamin C (vit C), and ischemia-exercise-vitamin C (vit C + exe) groups. Ischemia was achieved via unilateral ligation of the right common iliac artery. Contralateral muscles within the same animal served as controls. Exercise protocol consisted of 50-min intermittent level running performed every other day for 5 days. Vitamin C (100 mg/kg body wt) was administered intraperitoneally on a daily basis throughout the 14 days of the experiment. With regard to the EDL muscle, ischemia alone reduced muscle strength, which was not recovered after vitamin C administration. Exercise alone following ischemia induced the most severe structural damage and cross-sectional area decrease in the muscle, yet the reduction in tetanic tension was not significant. Exercise in conjunction with vitamin C administration preserved ischemia-induced EDL muscle tetanic tension. In the Sol muscle, a significant reduction in single twitch tension after vitamin C administration was found, whereas the tetanic force of the ischemic Sol was not significantly decreased compared with the contralateral muscles in any group. Ischemic Sol muscle cross-sectional area was reduced in all but the exe groups. In Sol, muscle strength was reduced in the vit C group, and mean cross-sectional area of ischemic Sol muscles was reduced in all groups except the exe group. These results illustrate that mild exercise, combined with a low dose of vitamin C supplementation, may have beneficial effects on ischemic EDL muscle with a smaller effect on the Sol muscle.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

Red blood cell deformability in patients with claudication after pain-free treadmill training

OBJECTIVES

To assess the effect of pain-free treadmill training on red blood cell deformability and walking distance in patients with claudication.

DESIGN

Randomized-controlled trial of exercise training.

SETTING

Patients were recruited from the primary care, vascular outpatient clinic.

PATIENTS

A total of 60 patients with peripheral arterial occlusive disease (stage II according to Leriche-Fontaine) were randomized into the treadmill program or a control group. Fifty-five patients completed the study (27 in the exercising group and 28 in the control group).

INTERVENTIONS

Patients in the exercising group were walking on the treadmill 3 times a week for 3 months. Each session consisted of 1 hour repetitive walking [performed to 85% of the pain-free walking time (PFWT)] was supervised by a qualified physiotherapist.

MAIN OUTCOME MEASUREMENTS

Changes in erythrocyte deformability and treadmill walking performance (PFWT, maximal walking time) were assessed in both groups before the study and after 3 months.

RESULTS

After 3 months of treadmill training, red blood cell deformability in the exercising group significantly increased (P<0.01). No significant changes were seen in the erythrocyte deformability in the control group. PFWT was prolonged by 102% from 191+/-34 to 386+/-60 seconds (P<0.01), and maximal walking time increased by 49% from 438+/-62 to 656+/-79 seconds (P<0.01) in the exercising group, whereas these changes were insignificant in the control group.

CONCLUSIONS

A significant improvement of walking ability over 3 months of pain-free treadmill training is associated with a significant increase in red cell deformability in patients with claudication.

Exercise training blunts microvascular rarefaction in the metabolic syndrome

Reduced skeletal muscle microvessel density (MVD) in the obese Zucker rat (OZR) model of the metabolic syndrome is a function of a chronic reduction in vascular nitric oxide (NO) bioavailability. Previous studies suggest that exercise can improve NO bioavailability and reduce chronic inflammation and that low vascular NO bioavailability may be associated with impaired angiogenic responses via increased matrix metalloproteinase (MMP)-2 and MMP-9 activity. As such, we hypothesized that chronic exercise (EX) would increase NO bioavailability in OZR and blunt microvascular rarefaction through reduced MMP activity, and potentially via altered plasma cytokine levels. Ten weeks of treadmill exercise (1 h/day, 5 days/wk, 22 m/min) reduced body mass and fasting insulin and triglyceride levels in EX-OZR vs. sedentary (SED) OZR. In EX-OZR, gastrocnemius muscle MVD was improved by 19 +/- 4%, whereas skeletal muscle arteriolar dilation and conduit arterial methacholine-induced NO release were increased. In EX-OZR, functional hyperemia was improved vs. SED-OZR, and minimum vascular resistance within perfused gastrocnemius muscle was reduced, although no change in arteriolar stiffness was identified. Western blotting and gelatin zymography demonstrated that neither expression nor activity of MMP-2 or MMP-9 was altered in skeletal muscle of EX vs. SED animals. Plasma markers of inflammation associated with angiogenesis, monocyte chemoattractant protein-1 and IL-1beta, were increased in SED-OZR and were reduced with training, whereas IL-13 was reduced in SED-OZR and increased with exercise. These data suggest that exercise-induced improvements in skeletal muscle MVD in OZR are associated with increased NO bioavailability and may stem from altered inflammatory profiles rather than MMP function.

Experimental Model of Pain-Free Treadmill Training in Patients with Claudication

OBJECTIVE

Treadmill training in claudication is often based on walking exercise to a pain threshold or longer to the maximum muscle pain of the lower limbs. This kind of exercise may cause an inflammatory response. The purpose of this study was to determine whether pain-free treadmill training using walking exercise to 85% of the distance to onset of claudication pain can significantly improve pain-free walking distance in patients with intermittent claudication and to evaluate whether this kind of program may induce an inflammatory response leading to the progression of atherosclerosis.

DESIGN

A total of 98 patients aged 50-70 yrs with stable intermittent claudication were randomized into a supervised treadmill training program or a comparison group. Patients in the treatment group participated in 12 wks of supervised treadmill training. We examined the effects of 12 wks of pain-free treadmill training on pain-free walking distance, total leukocyte count, neutrophil count, and microalbuminuria in patients with claudication.

RESULTS

A total of 80 participants completed the program. Exercise rehabilitation increased the time to onset of claudication pain by 119.2%, from 87.4 +/- 38 m to 191.6 +/- 94.8 m (P < 0.001). There was no increase in total leukocyte count, neutrophil count, or microalbuminuria after 12 wks of treadmill exercise (P > 0.05)

CONCLUSION

A pain-free training program can be used in the treatment of claudication as a low-risk program, increasing walking ability without potential harmful effects of ischemia-reperfusion injury.

The Impact of Gastrocnemius Muscle Cell Changes in Chronic Venous Insufficiency

OBJECTIVE

To investigate the pathological and metabolic changes in the gastrocnemius muscle in patients with chronic vein insufficiency (CVI).

METHOD

Thirty-six patients with varicose veins were investigated by ambulatory venous pressure (AVP) and duplex ultrasonography. Twelve age and height-matched controls were used for comparison. Patients and controls consented to participate in this study. Twenty-one patients with primary vein varicose (group AI) and 15 patients (group AII) with primary deep venous valve incompetence (DVI) underwent biopsies of the gastrocnemius muscle during operation. Adductor biopsies obtained from the same limbs served as a control group (group B) and specimens from controls subjects without venous disease served as the second control group (group C). All the specimens were investigated by superoxide dismutase (SOD), nitric oxide (NO), Na+-K+-ATPase, Ca2+-ATPase and lactic acid (LD) determinations. Samples were subjected to light and electron microscopy following H & E staining, special ATPase, cytochrome oxidase/succinate dehydrogenase (COX/SDH) stains.

RESULTS

Normal muscle architecture was seen following H & E, ATPase and COX/SDH staining and normal cell metabolism was observed in specimens of groups B and C. In group A, pathological changes were encountered in the gastrocnemius muscle including disseminated myofibril atrophy, cell denaturation and necrosis, inflammatory cell infiltration, proliferation and dilation of interfascicular veins. ATPase staining (pH 9.4) demonstrated grouping of atrophic fibres, especially type I myofibril grouping, accompanied by moderate to severe atrophy of type II muscle fibres. However, no patient had selective type I fibre atrophy. Enhanced enzymatic activity in single or multiple myofibrils was demonstrated by COX/SDH staining in approximately half of the specimens in group AII. In group AII, electron microscopy showed swelling, myelin figure denaturation of mitochondria, disruption of the myofibrils and increased lipid droplets in the gastrocnemius muscle. Increased concentration of LD was found in most specimens from group A patients. There were also reductions of SOD, NO, biochemical activity of Na+-K+-ATPase, Ca2+-ATPase with increasing concentration of LD in these patients, most prominently in group AII. We found correlation between AVP assessments and the biochemical measurements as well as morphological appearances of the gastrocnemius muscle.

CONCLUSION

Venous hypertension results in pathophysiological changes in the gastrocnemius muscles of patients with DVI, associated with decreased calf pump function.

Intermittent Claudication: Exercise-increased Walking Distance is Not Related to Improved Cardiopulmonary Fitness

OBJECTIVES

To assess if exercise training improves the symptoms of intermittent claudication by improvement in cardiopulmonary fitness.

METHODS

Claudication distance (CD), maximum walking distance (MWD), calf endurance (repetitive heel raises), cardiovascular fitness (VO2 peak), and ankle-brachial pressure index (ABPI) were measured in 16 subjects with intermittent claudication before, and following an 8-week treadmill training programme.

RESULTS

Training resulted in a median increase in CD of 65.5 m (p<0.01), MWD of 339.5 m (p<0.001) and HR of 19 (p<0.03). Notably, improvements in MWD correlated with those in HR (p=0.001; R=0.75). There was no training-associated change in VO2 peak (median increase of only 0.35 ml/kg/min; p=0.60) or ABPI (median increase of only 0.01; p=0.64).

CONCLUSION

In this study, overall improvement in claudication was not related to an improvement in cardiopulmonary fitness.

Effect of Physical Activity after Recent Deep Venous Thrombosis: A Cohort Study

PURPOSE

To determine whether increased physical activity 1 month after deep vein thrombosis (DVT) led to worsening of venous symptoms and signs within the subsequent 3 months.

METHODS

By a multicenter prospective cohort study of patients with acute DVT, we used validated questionnaires at baseline, 1 month, and 4 months post-DVT for each exposure, using the Godin Questionnaire to measure physical activity, the VEINES-QOL to measure disease severity, and the postthrombotic syndrome (PTS) scale to measure symptoms and signs usually attributed to sequelae of DVT.

RESULTS

Of 301 patients followed for 4 months, 25% were inactive and 25% were only mildly active before their DVT. In univariate analysis, physical activity at 1 month was not associated with a change in PTS score between 1 month and 4 months (P=0.42). After adjusting for the potential confounders of age, sex, pre-DVT physical activity, and disease severity at 1 month, the results suggested that higher physical activity levels at 1 month may be protective against worsening of the PTS score over the subsequent 3 months. Compared with those who were inactive at 1 month, the adjusted OR was 0.93 (95%CI: 0.47, 1.87) for mildly to moderately active persons, and 0.52 (95%CI: 0.24, 1.15) for highly active persons. Among patients who were active pre-DVT (N=220), 55.5% had returned to their previous levels of physical activity or greater within 4 months.

CONCLUSIONS

For most persons, exercise at 1 month post-DVT does not appear to worsen venous symptoms and signs over the subsequent 3 months, and more than 50% resume their usual level of activity within 4 months.

Endartery stenosis of the popliteal artery mimicking gastrocnemius strain: a case report

This report presents a case of leg pain in a recreational athlete that was caused by a stenotic lesion of an endartery branch of the popliteal artery. Isolated areas of arterial stenosis are rarely reported in the sports medicine literature as the primary cause of leg pain. This may be due in part to the difficulty of obtaining the diagnosis. This study includes a review of the relevant anatomic, pathophysiologic, diagnostic, and therapeutic considerations and concludes with a discussion of the potentially underrecognized significance of arterial stenosis in the sports population.

Arteriolar Endothelial Dysfunction Is Restored in Ischaemic Muscles by Chronic Electrical Stimulation

Chronic intermittent electrical stimulation (15 min on, 85 min off, seven times per day) eliminated endothelial dysfunction of pre-capillary arterioles in ischaemic rat ankle flexor muscles. Responses to acetylcholine were restored from constriction to dilation, and the reduced dilation to bradykinin was corrected by 1 week of stimulation. Administration of the NOS inhibitor N(omega)-nitro-L-arginine for 1 week impaired arteriolar reactivity in a similar way to ischaemia, and dilator function was likewise restored by chronic stimulation. This suggests that nitric oxide production in the microcirculation is depressed by chronic ischaemia and that chronic electrical stimulation can specifically reverse this deficit. Stimulation applied to ischaemic muscles for 2 weeks also increased the numbers of microvessels immunostained for alpha-smooth muscle actin and the numbers of eNOS-positive microvessels and capillaries. These findings help to elucidate the mechanism of the beneficial effect of exercise in the treatment of peripheral vascular diseases by showing that muscle activity can improve both function and structural capacity of the microvasculature.

Management options for patients with intermittent claudication

Peripheral arterial disease is a chronic condition, affecting a significant proportion of the adult population. Intermittent claudication is the earliest clinical manifestation of peripheral arterial disease and the patient's walking distance can be significantly reduced. This restriction can profoundly disrupt activities of living. Treatment options vary according to the level of the disease and co-morbidity of the patient. Current evidence to support risk factor assessment highlights the role of the nurse in encouraging lifestyle modification.

Metabolic inertia in contracting skeletal muscle: a novel approach for pharmacological intervention in peripheral vascular disease

Peripheral vascular disease (PVD) is generally accepted to result in the failure of skeletal muscle blood flow to increase adequately at the onset of muscular work. There are currently no routine pharmacological interventions towards the treatment of PVD, however, recent Phase III trials in the USA have demonstrated the clinical potential of the phosphodiesterase III inhibitor Cilostazol for pain-free and maximal walking distances in patients with intermittent claudication. PVD is characterized by a marked reliance on oxygen-independent routes of ATP regeneration (phosphocreatine hydrolysis and glycolysis) in skeletal muscle during contraction and the rapid onset of muscular pain and fatigue. The accumulation of metabolic by-products of oxygen-independent ATP production (hydrogen and lactate ions and inorganic phosphate) has long been associated with an inhibition in contractile function in both healthy volunteers and PVD patients. Therefore, any strategy that could reduce the reliance upon ATP re-synthesis from oxygen-independent routes, and increase the contribution of oxygen-dependent (mitochondrial) ATP re-synthesis, particularly at the onset of exercise, might be expected to improve functional capacity and be of considerable therapeutic value. Historically, the increased contribution of oxygen-independent ATP re-synthesis to total ATP generation at the onset of exercise has been attributed to a lag in muscle blood flow limiting oxygen delivery during this period. However, recent evidence suggests that limited inertia is present at the level of oxygen delivery, whilst considerable inertia exists at the level of mitochondrial enzyme activation and substrate supply. In support of this latter hypothesis, we have reported on a number of occasions that activation of the pyruvate dehydrogenase complex, using pharmacological interventions, can markedly reduce the dependence on ATP re-synthesis from oxygen-independent routes at the onset of muscle contraction. This review will focus on these findings and will highlight the pyruvate dehydrogenase complex as a novel therapeutic target towards the treatment of peripheral vascular disease, or any other disease state where premature muscular fatigue is prevalent due to metabolite accumulation.

The vascular nurse in practice: Results of prescribed exercise training in patients with intermittent claudication

Intermittent claudication (IC) is a mild stage of peripheral arterial disease that affects between 3% and 7% of the population and up to 1 in 5 patients over the age of 75 years. Risk factors such as hypertension, hyperlipidemia, diabetes, smoking, and genetics increase the incidence of peripheral arterial disease. Patients with IC have limitations in functional capacity and can benefit from regular exercise. Walking is the preferred mode of exercise and improves the symptoms of claudication in several ways. Vascular nurses can play an important role during exercise therapy. A personalized, home-based exercise program can be developed, and nurses can assist and motivate patients during follow-up periods. Helping patients to quit smoking and control other risk-factor modifications (ie, high blood pressure and lipid levels) also has high priority in daily practice of the vascular nurse. This prospective study will illustrate the results of prescribed home-based exercise training by a vascular nurse on the maximum painless walking distance for patients with IC and will be applied to subgroups of vascular pathology.

Chronic Transcutaneous Electrical Stimulation of Calf Muscles Improves Functional Capacity without Inducing Systemic Inflammation in Claudicants

OBJECTIVES

To assess whether electrical stimulation of ischaemic calf muscles in claudicants causes a systemic inflammatory response and to evaluate effects of its chronic application on muscle function and walking ability.

DESIGN

Prospective randomised controlled trial of calf muscle stimulation.

MATERIALS AND METHODS

Stable claudicants were randomised to receive either active chronic low frequency (6 Hz) motor stimulation (n=15) or, as a control treatment, submotor transcutaneous electrical nerve (TENS) stimulation (n=15) of calf muscles in one leg, 3 x 20 min per day for four weeks. Leucocyte activation was quantified by changes in cell morphology, vascular permeability by urinary albumin:creatinine ratio (ACR), calf muscle function by isometric twitch contractions and walking ability by treadmill performance pre- and post-intervention.

RESULTS

Acute active muscle stimulation activated leucocytes less (28% increase) than a standard treadmill test (81% increase) and did not increase ACR. Chronic calf muscle stimulation significantly increased pain-free walking distance by 35 m (95% CI 17, 52, P<0.001) and maximum walking distance by 39 m (95% CI 7, 70, P<0.05) while control treatment had no effect. Active stimulation prevented fatigue of calf muscles during isometric electrically evoked contractions by abolishing the slowing of relaxation that was responsible for loss of force.

CONCLUSIONS

Chronic electrical muscle stimulation is an effective treatment for alleviating intermittent claudication which, by targeted activation of a small muscle mass, does not engender a significant systemic inflammatory response.

Exercise increases endostatin in circulation of healthy volunteers

Background

Physical inactivity increases the risk of atherosclerosis. However, the molecular mechanisms of this relation are poorly understood. A recent report indicates that endostatin, an endogenous angiostatic factor, inhibits the progression of atherosclerosis, and suggests that reducing intimal and atherosclerotic plaque tissue neovascularization can inhibit the progression atherosclerosis in animal models. We hypothesize that exercise can elevate the circulatory endostatin level. Hence, exercise can protect against one of the mechanisms of atherosclerosis.

Results

We examined treadmill exercise tests in healthy volunteers to determine the effect of exercise on plasma levels of endostatin and other angiogenic regulators. Oxygen consumption (VO₂) was calculated. Plasma levels of endostatin, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) were determined using ELISA. The total peak VO₂ (L) in 7 male subjects was 29.5 ± 17.8 over a 4–10 minute interval of exercise. Basal plasma levels of endostatin (immediately before exercise) were 20.3 ± 3.2 pg/ml, the plasma levels increased to 29.3 ± 4.2, 35.2 ± 1.8, and 27.1 ± 2.2 ng/ml, at 0.5, 2, and 6 h, respectively, after exercise. There was a strong linear correlation between increased plasma levels of endostatin (%) and the total peak VO₂ (L) related to exercise (R² = 0.9388; P < 0.01). Concurrently, VEGF levels decreased to 28.3 ± 6.4, 17.6 ± 2.4, and 26.5 ± 12.5 pg/ml, at 0.5, 2, and 6 h, respectively, after exercise. There were no significant changes in plasma bFGF levels in those subjects before and after exercise.

Conclusions

The results suggest that circulating endostatin can be significantly increased by exercise in proportion to the peak oxygen consumption under physiological conditions in healthy volunteers. These findings may provide new insights into the molecular links between physical inactivity and the risk of angiogenesis dependent diseases such as atherosclerosis.

Acute effects of exercise in patients with previous deep venous thrombosis: impact of the postthrombotic syndrome

BACKGROUND

The postthrombotic syndrome (PTS) occurs frequently after deep venous thrombosis (DVT) and is believed to worsen with upright posture and physical activity. However, the effects of exercise in patients with previous DVT have not been studied.

STUDY OBJECTIVES

To determine whether previous DVT and PTS limit the ability to exercise, and whether exercise increases the severity of venous symptoms and signs.

DESIGN AND SETTING

A repeated-measures cohort study that was conducted at a university-affiliated teaching hospital, 1999-2000.

PARTICIPANTS

Subjects with a first episode of unilateral DVT at least 1 year earlier were recruited from the Thrombosis Clinic (total, 41 subjects; with PTS, 19 subjects).

INTERVENTION

Treadmill exercise session.

MEASUREMENTS AND RESULTS

Venous symptoms, calf muscle fatigability, flexibility, and leg volume before and after treadmill exercise were measured and compared. Exercise did not worsen venous symptoms, despite a higher gain in affected leg volume in subjects with PTS vs subjects without PTS (mean difference: affected leg, 53 mL; unaffected leg, -15 mL; p = 0.018). Calf flexibility significantly improved after exercise in subjects with PTS (gastrocnemius: affected-unaffected, PTS vs no PTS + 4.5 degrees, p = 0.0029; soleus: affected-unaffected, PTS vs no PTS + 5.7 degrees, p = 0.0011).

CONCLUSIONS

Exercise did not acutely exacerbate symptoms and, in subjects with PTS, resulted in improved flexibility in the affected leg. Our findings suggest that treadmill or similar exercise is unlikely to make symptoms of PTS worse, and may improve flexibility. Further study is indicated to determine whether a regular exercise-training program might have a role in the management of patients with PTS, since, to date, the treatment options for this condition are limited.

What constitutes best medical therapy for peripheral arterial disease?

Peripheral arterial disease (PAD) is associated with a high morbidity and mortality, largely from coronary and cerebrovascular disease, which often overshadows the PAD itself. Best Medical Therapy (BMT), comprising smoking cessation, antiplatelet agent use, cholesterol reduction, exercise therapy, and the diagnosis and treatment of hypertension and diabetes mellitus; is evidenced based and can result in significant reductions in cardiovascular risk, as well as some improvement in PAD. Previous data have largely been restricted to patients with coronary artery disease, and their relevance to PAD has been extrapolated. However, data are now starting to become available, such as the Heart Protection Study, with data specific to PAD patients. This article reviews the data regarding the use of BMT in patients with PAD, and based on this, makes recommendations for the use of BMT in this group of patients.

Systemic atherosclerosis risk and the mandate for intervention in atherosclerotic peripheral arterial disease

Peripheral arterial disease (PAD), characterized by obstruction of the arteries in the lower limbs, is an important manifestation of atherosclerosis. There are >10 million individuals with PAD in the United States alone, and as the overall population in developed countries ages, PAD will become increasingly prevalent. Many individuals with PAD are asymptomatic and therefore remain undiagnosed and untreated. Most patients with PAD are at high risk for having a serious coronary or cerebrovascular event. Even for patients in whom symptoms, such as leg pain, are clearly evident, current treatment strategies tend to ignore the systemic nature of the disease and do not reduce overall atherosclerotic risk. Proven medical treatment options for patients with intermittent claudication include smoking cessation, exercise, and cilostazol. Pentoxifylline appears marginally effective. Several novel therapies for PAD are currently under investigation. Of particular interest are the observations from some studies that show that lipid-lowering therapy might be of benefit to PAD patients. The results of 2 ongoing prospective trials of dyslipidemic therapy in claudicants should further clarify the benefits of reducing serum lipid levels in patients with established PAD.

Exercise training and smoking cessation as the cornerstones of managing claudication

Based on research, the classic recommendation to prevent progression of lower extremity peripheral arterial disease (PAD) is "start exercising and stop smoking." Unfortunately, a paramount problem for clinicians is motivating targeted individuals to begin and adhere to an exercise regimen and quit smoking. The purpose of this review is to provide the most current information regarding exercise training and smoking cessation. It is hoped that this article will help health care professionals present accurate information to their patients with PAD, address the difficulties in lifestyle change, and intervene effectively.