Aerobic High Intensity One-Legged Interval Cycling Improves Peak Oxygen Uptake in Chronic Obstructive Pulmonary Disease Patients; No Additional Effect from Hyperoxia

Fidelity and tolerability of two high-intensity interval training protocols in patients with COPD: a randomised cross-over pilot study

Objectives

High-intensity interval training (HIIT) during pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD) may alleviate the symptom burden, but the fidelity and tolerability of HIIT using long or short intervals in patients with COPD are unknown.

Methods

Twelve patients with moderate-to-severe COPD were included in a randomised cross-over pilot study. They completed two supervised HIIT protocols (4×4 and 10×1). To compare the two HIIT protocols, completed training amount, exercise intensity and perceived tolerability (assessed by a 10-point Likert scale) were integrated in a red-amber-green rating system. If a training session received a red ranking, it was considered unacceptable, if it received an amber ranking it was applicable with precautions, and if it received a green ranking it was considered feasible.

Results

All patients completed the total training amount in both protocols. The 4×4 protocol resulted in three amber training sessions due to low perceived tolerability. The 10×1 protocol resulted in two red training sessions due to intensity reductions, and two amber training sessions because of low perceived tolerability. There was no statistical difference in perceived tolerability or time spent with an HR ≥85% of HR_max.

Conclusions

HIIT using longer intervals (4×4) at a relatively lower intensity resulted in higher fidelity expressed by fewer adjustments to the protocol, whereas there was no difference between protocols in perceived tolerance. The 4×4 protocol seems to have a higher fidelity compared with the 10×1 protocol in patients with moderate-to-severe COPD.

Trial registration number

NCT05273684.

Relationship between perceived and neuromuscular fatigue in COPD patients with chronic respiratory failure with long-term oxygen therapy: a cross-sectional study

PURPOSE

To evaluate perceived fatigue (PF) and neuromuscular fatigue (NMF) in patients with COPD and chronic respiratory failure (CRF) on long-term oxygen therapy (CRF-COPD group), and the relationships between PF, NMF, patient's characteristics, comparing severe patients with COPD to patients without CRF (COPD group).

METHODS

This cross-sectional study compared 19 CRF-COPD patients with 10 COPD patients attending a rehabilitation program. PF was determined by Fatigue Severity Scale (FSS), while dyspnea by the Barthel Dyspnea Index (BDI). We assessed quadriceps NMF via electrical nerve stimulation during and following a Maximal Voluntary Contraction (MVC) detecting changes after a Constant Workload Cycling Test (CWCT) at 80% of the peak power output at exhaustion.

RESULTS

CRF-COPD patients showed higher PF (+ 1.79 of FSS score, p = 0.0052) and dyspnea (+ 21.03 of BDI score, p = 0.0023) than COPD patients. After the fatiguing task and normalization for the total work, there was a similar decrease in the MVC (CRF-COPD -1.5 ± 2.4 vs COPD -1.1 ± 1.2% baseline kJ^-1, p = 0.5819), in the potentiated resting twitch force (CRF-COPD -2.8 ± 4.7 vs COPD -2.0 ± 3.3% baseline kJ^-1, p = 0.7481) and in the maximal voluntary activation (CRF-COPD -0.1 ± 3.9 vs COPD -0.9 ± 1.2 -2.0 ± 3.3% baseline kJ^-1, p = 0.4354). FSS and BDI were closely related (R = 0.5735, p = 0.0011), while no correlation between PF and NMF was found.

CONCLUSION

Patients with CRF-COPD develop higher levels of perceived fatigue and dyspnea than patients with COPD; while neuromuscular fatigue is similar, suggesting a mismatch between symptoms and neuromuscular dysfunction.

Single Leg Cycling Offsets Reduced Muscle Oxygenation in Hypoxic Environments

The intensity of large muscle mass exercise declines at altitude due to reduced oxygen delivery to active muscles. The purpose of this investigation was to determine if the greater limb blood flow during single-leg cycling prevents the reduction in tissue oxygenation observed during traditional double-leg cycling in hypoxic conditions. Ten healthy individuals performed bouts of double and single-leg cycling (4, four-minute stages at 50−80% of their peak oxygen consumption) in hypoxic (15% inspired O2) and normoxic conditions. Heart rate, mean arterial pressure, femoral blood flow, lactate, oxygenated hemoglobin, total hemoglobin, and tissue saturation index in the vastus lateralis were recorded during cycling tests. Femoral blood flow (2846 ± 912 mL/min) and oxygenated hemoglobin (−2.98 ± 3.56 au) during single-leg cycling in hypoxia were greater than double-leg cycling in hypoxia (2429 ± 835 mL/min and −6.78 ± 3.22 au respectively, p ≤ 0.01). In addition, tissue saturation index was also reduced in the double-leg hypoxic condition (60.2 ± 3.1%) compared to double-leg normoxic (66.0 ± 2.4%, p = 0.008) and single-leg hypoxic (63.3 ± 3.2, p < 0.001) conditions. These data indicate that while at altitude, use of reduced muscle mass exercise can help offset the reduction in tissue oxygenation observed during larger muscle mass activities allowing athletes to exercise at greater limb/muscle specific intensities.

Effect of small vs large muscle mass endurance training on maximal oxygen uptake in organ transplanted recipients

Maximal oxygen consumption (V̇O_2max) is impaired in heart (HTx), kidney (KTx), and liver (LTx) transplanted recipients and the contribution of the cardiovascular, central, and peripheral (muscular) factors in affecting V̇O_2max improvement after endurance training (ET) has never been quantified in these patients. ET protocols involving single leg cycling (SL) elicit larger improvements of the peripheral factors affecting O₂ diffusion and utilization than the double leg (DL) cycling ET. Therefore, this study aimed to compare the effects of SL-ET vs DL-ET on V̇O_2max. We determined the DL-V̇O_2max and maximal cardiac output before and after 24 SL-ET vs DL-ET sessions on 33 patients (HTx = 13, KTx = 11 and LTx = 9). The DL-V̇O_2max increased by 13.8% ± 8.7 (p < 0.001) following the SL-ET, due to a larger maximal O₂ systemic extraction; meanwhile, V̇O_2max in DL-ET increased by 18.6% ± 12.7 (p < 0.001) because of concomitant central and peripheral adaptations. We speculate that in transplanted recipients, SL-ET is as effective as DL-ET to improve V̇O_2max and that the impaired peripheral O₂ extraction and/or utilization play an important role in limiting V̇O_2max in these types of patients. Novelty: SL-ET increases V̇O_2max in transplanted recipients because of improved peripheral O₂ extraction and/or utilization. SL-ET is as successful as DL-ET to improve the cardiorespiratory fitness in transplanted recipients. The model of V̇O_2max limitation indicates the peripheral factors as a remarkable limitation to the V̇O_2max in these patients.

Exercise training in COPD: muscle O2 transport plasticity

Both convective oxygen (O₂) transport to, and diffusive transport within, skeletal muscle are markedly diminished in patients with COPD. However, it is unknown how these determinants of peak muscle O₂ uptake (V'_mO2peak) respond to exercise training in patients with COPD. Therefore, the purpose of this study was to assess the plasticity of skeletal muscle O₂ transport determinants of V'_mO2peak in patients with COPD.Adaptations to 8 weeks of single-leg knee-extensor exercise training were measured in eight patients with severe COPD (mean±sem forced expiratory volume in 1 s (FEV₁) 0.9±0.1 L) and eight healthy, well-matched controls. Femoral arterial and venous blood samples, and thermodilution-assessed leg blood flow were used to determine muscle O₂ transport and utilisation at maximal exercise pre- and post-training.Training increased V'_mO2peak in both COPD (by ∼26% from 271±29 to 342±35 mL·min^-1) and controls (by ∼32% from 418±37 to 553±41 mL·min^-1), restoring V'_mO2peak in COPD to only ∼80% of pre-training control V'_mO2peak Muscle diffusive O₂ transport increased similarly in both COPD (by ∼38% from 6.6±0.9 to 9.1±0.9 mL·min^-1·mmHg^-1) and controls (by ∼36% from 10.4±0.7 to 14.1±0.8 mL·min^-1·mmHg^-1), with the patients reaching ∼90% of pre-training control values. In contrast, muscle convective O₂ transport increased significantly only in controls (by ∼26% from 688±57 to 865±69 mL·min^-1), leaving patients with COPD (438±45 versus 491±51 mL·min^-1) at ∼70% of pre-training control values.While muscle diffusive O₂ transport in COPD was largely restored by exercise training, V'_mO2peak remained constrained by limited plasticity in muscle convective O₂ transport.

Is Structured Exercise Performed with Supplemental Oxygen a Promising Method of Personalized Medicine in the Therapy of Chronic Diseases?

Aim: This systematic review aimed to explore the literature to identify in which types of chronic diseases exercise with supplemental oxygen has previously been utilized and whether this type of personalized therapy leads to superior effects in physical fitness and well-being. Methods: Databases (PubMed/MEDLINE, CINHAL, EMBASE, Web of knowledge and Cochrane Library) were searched in accordance with PRISMA. Eligibility criteria included adult patients diagnosed with any type of chronic diseases engaging in supervised exercise training with supplemental oxygen compared to normoxia. A random-effects model was used to pool effect sizes by standardized mean differences (SMD). Results: Out of the identified 4038 studies, 12 articles were eligible. Eleven studies were conducted in chronic obstructive pulmonary disease (COPD), while one study included coronary artery disease (CAD) patients. No statistical differences were observed for markers of physical fitness and patient-reported outcomes on well-being between the two training conditions (SMD −0.10; 95% CI −0.27, 0.08; p = 0.26). Conclusions: We found that chronic exercise with supplemental oxygen has mainly been utilized for COPD patients. Moreover, no superior long-term adaptations on physical fitness, functional capacity or patient-reported well-being were found, questioning the role of this method as a personalized medicine approach. Prospero registration: CRD42018104649.

The performance and aerobic endurance effects of high-intensity versus moderate-intensity continuous running

The aim of the present study was to investigate the performance and aerobic endurance effects of high-intensity (HICR) versus moderate-intensity continuous running (MICR), which were nonmatched for total work. Twenty healthy recreational athletes (aged 28 ± 5 years) were randomly assigned to an HICR, MICR, or no-intervention control (C) group. The HICR group (n = 7) performed a 20-min strenuous, almost exhausting, run above lactate threshold (LT) at ∼88% of maximal heart rate (HR_max), whereas the MICR group (n = 7) performed a 40-min run at ∼80% HR_max. Both the HICR and MICR groups performed 3 intervention sessions a week, in addition to ∼60% of their regular aerobic exercise, for 10 weeks. The C group (n = 6) performed regular physical exercise throughout the study. Time to exhaustion, during a ∼4-8-min ramp test procedure, was significantly increased by 23% and 24% (P < 0.01) following HICR or MICR, respectively, with no significant difference in the change in time to exhaustion (P = 1.00) at pre- to post-training between the 2 training modalities (HICR and MICR). In the HICR group, maximal oxygen consumption and velocity at LT increased significantly by 5.0% and 6.8% (P < 0.01), respectively. The MICR group increased relative maximal oxygen consumption (mL·kg^-1·min^-1) significantly by 4.7% (P < 0.05), whereas the pulmonary respiratory gas-exchange ratio was significantly decreased at a submaximal workload by 4.2% (P < 0.01), indicating enhanced fat oxidation. No performance or physiological effects were observed in the C group. The present study indicates that even with a substantially lower total energy turnover, HICR can be as performance enhancing as MICR. Moreover, HICR can increase maximal aerobic power, whereas MICR may enhance fat oxidation.

Size Exponents for Scaling Maximal Oxygen Uptake in Over 6500 Humans: A Systematic Review and Meta-Analysis

BACKGROUND

Maximal oxygen uptake ([Formula: see text] _2max) is conventionally normalized to body size as a simple ratio or using an allometric exponent < 1. Nevertheless, the most appropriate body size variable to use for scaling and the value of the exponent are still enigmatic. Studies tend to be based on small samples and can, therefore, lack precision.

OBJECTIVE

The objective of this systematic review was to provide a quantitative synthesis of reported static allometric exponents used for scaling [Formula: see text] _2max to whole body mass and fat-free mass.

METHODS

Eight electronic databases (CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, PubMed, Scopus, SPORTDiscus and Web of Science) were searched for relevant studies published up to January 2016. Search terms included 'oxygen uptake', 'cardiorespiratory fitness', '[Formula: see text] _2max', '[Formula: see text] _2peak', 'scaling' and all interchangeable terms. Inclusion criteria included human cardiorespiratory fitness data; cross-sectional study designs; an empirical derivation of the exponent; reported precision statistics; and reported information regarding participant sex, age and sports background, [Formula: see text] _2max protocol, whole body composition protocol and line-fitting methods. A random-effects model was used to quantify weighted pooled exponents and 95% confidence limits (Cls). Heterogeneity was quantified with the tau-statistic (τ). Meta-regression was used to quantify the impact of selected moderator variables on the exponent effect size. A 95% prediction interval was calculated to quantify the likely range of true fat-free mass exponents in similar future studies, with this distribution used to estimate the probability that an exponent would be above theorised universal values of [Formula: see text].

RESULTS

Thirty-six studies, involving 6514 participants, met the eligibility criteria. Whole body mass and fat-free mass were used as the scaling denominator in 27 and 15 studies, respectively. The pooled allometric exponent (95% Cls) was found to be 0.70 (0.64 to 0.76) for whole body mass and 0.90 (0.83 to 0.96) for fat-free mass. The between-study heterogeneity was greater for whole body mass (τ = ±0.15) than for fat-free mass (τ = ±0.11). Participant sex explained 30% of the between-study variability in the whole body mass exponent, but the influence on the fat-free mass exponent was trivial. The whole body mass exponent of 0.52 (0.40 to 0.64) for females was substantially lower than the 0.76 (0.70 to 0.83) for males, whereas the fat-free mass exponent was similar for both sexes. The effects of all other moderators were trivial. The 95% PI for fat-free mass ranged from 0.68 to 1.12. The estimated probability of a true fat-free mass exponent in a future study being greater than [Formula: see text] power scaling is 0.98 (very likely) and 0.92 (likely), respectively.

CONCLUSIONS

In this quantitative synthesis of published studies involving over 6500 humans, the whole body mass exponent was found to be spuriously low and prone to substantial heterogeneity. We conclude that the scaling of [Formula: see text] _2max in humans is consistent with the allometric cascade model with an estimated prediction interval for the fat-free mass exponent not likely to be consistent with the [Formula: see text] power laws.

Oxygen for breathlessness in patients with chronic obstructive pulmonary disease who do not qualify for home oxygen therapy

BACKGROUND

Breathlessness is a cardinal symptom of chronic obstructive pulmonary disease (COPD). Long-term oxygen therapy (LTOT) is given to improve survival time in people with COPD and severe chronic hypoxaemia at rest. The efficacy of oxygen therapy for breathlessness and health-related quality of life (HRQOL) in people with COPD and mild or no hypoxaemia who do not meet the criteria for LTOT has not been established.

OBJECTIVES

To determine the efficacy of oxygen versus air in mildly hypoxaemic or non-hypoxaemic patients with COPD in terms of (1) breathlessness; (2) HRQOL; (3) patient preference whether to continue therapy; and (4) oxygen-related adverse events.

SEARCH METHODS

We searched the Cochrane Airways Group Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase, to 12 July 2016, for randomised controlled trials (RCTs). We handsearched the reference lists of included articles.

SELECTION CRITERIA

We included RCTs of the effects of non-invasive oxygen versus air on breathlessness, HRQOL or patient preference to continue therapy among people with COPD and mild or no hypoxaemia (partial pressure of oxygen (PaO₂) > 7.3 kPa) who were not already receiving LTOT. Two review authors independently assessed articles for inclusion in the review.

DATA COLLECTION AND ANALYSIS

Two review authors independently collected and analysed data. We assessed risk of bias by using the Cochrane 'Risk of bias tool'. We pooled effects recorded on different scales as standardised mean differences (SMDs) with 95% confidence intervals (CIs) using random-effects models. Lower SMDs indicated decreased breathlessness and reduced HRQOL. We performed subanalyses and sensitivity analyses and assessed the quality of evidence according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.

MAIN RESULTS

Compared with the previous review, which was published in 2011, we included 14 additional studies (493 participants), excluded one study and included data for meta-analysis of HRQOL. In total, we included in this review 44 studies including 1195 participants, and we included 33 of these (901 participants)in the meta-analysis.We found that breathlessness during exercise or daily activities was reduced by oxygen compared with air (32 studies; 865 participants; SMD -0.34, 95% CI -0.48 to -0.21; I² = 37%; low-quality evidence). This translates to a decrease in breathlessness of about 0.7 points on a 0 to 10 numerical rating scale. In contrast, we found no effect of short-burst oxygen given before exercise (four studies; 90 participants; SMD 0.01, 95% CI -0.26 to 0.28; I² = 0%; low-quality evidence). Oxygen reduced breathlessness measured during exercise tests (25 studies; 442 participants; SMD -0.34, 95% CI -0.46 to -0.22; I² = 29%; moderate-quality evidence), whereas evidence of an effect on breathlessness measured in daily life was limited (two studies; 274 participants; SMD -0.13, 95% CI, -0.37 to 0.11; I² = 0%; low-quality evidence).Oxygen did not clearly affect HRQOL (five studies; 267 participants; SMD 0.10, 95% CI -0.06 to 0.26; I² = 0%; low-quality evidence). Patient preference and adverse events could not be analysed owing to insufficient data.

AUTHORS' CONCLUSIONS

We are moderately confident that oxygen can relieve breathlessness when given during exercise to mildly hypoxaemic and non-hypoxaemic people with chronic obstructive pulmonary disease who would not otherwise qualify for home oxygen therapy. Most evidence pertains to acute effects during exercise tests, and no evidence indicates that oxygen decreases breathlessness in the daily life setting. Findings show that oxygen does not affect health-related quality of life.

Effect of "add-on" interventions on exercise training in individuals with COPD: a systematic review

The aim of this review was to identify the effectiveness of therapies added on to conventional exercise training to maximise exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Electronic databases were searched, identifying trials comparing exercise training with exercise training plus "add-on" therapy. Outcomes included peak oxygen uptake (V'_O2peak), work rate and incremental/endurance cycle and field walking tests. Individual trial effects on exercise capacity were extracted and collated into eight subgroups and pooled for meta-analysis. Sensitivity analyses were conducted to explore the stability of effect estimates across studies employing patient-centred designs and those deemed to be of "high" quality (PEDro score >5 out of 10). 74 studies (2506 subjects) met review inclusion criteria. Interventions spanned a broad scope of clinical practice and were most commonly evaluated via the 6-min walking distance and V'_O2peak. Meta-analysis revealed few clinically relevant and statistically significant benefits of "add-on" therapies on exercise performance compared with exercise training. Benefits favouring "add-on" therapies were observed across six different interventions (additional exercise training, noninvasive ventilation, bronchodilator therapy, growth hormone, vitamin D and nutritional supplementation). The sensitivity analyses included considerably fewer studies, but revealed minimal differences to the primary analysis. The lack of systematic benefits of "add-on" interventions is a probable reflection of methodological limitations, such as "one size fits all" eligibility criteria, that are inherent in many of the included studies of "add-on" therapies. Future clarification regarding the exact value of such therapies may only arise from adequately powered, multicentre clinical trials of tailored interventions for carefully selected COPD patient subgroups defined according to distinct clinical phenotypes.

Provocative issues in heart disease prevention

In this article, new areas of cardiovascular (CV) prevention and rehabilitation research are discussed: high-intensity interval training (HIIT) and new concepts in nutrition. HIIT consists of brief periods of high-intensity exercise interspersed by periods of low-intensity exercise or rest. The optimal mode according our work (15-second exercise intervals at peak power with passive recovery intervals of the same duration) is associated with longer total exercise time, similar time spent near peak oxygen uptake (VO2 peak) VO2 peak, and lesser perceived exertion relative to other protocols that use longer intervals and active recovery periods. Evidence also suggests that compared with moderate-intensity continuous exercise training, HIIT has superior effects on cardiorespiratory function and on the attenuation of multiple cardiac and peripheral abnormalities. With respect to nutrition, a growing body of evidence suggests that the gut microbiota is influenced by lifestyle choices and might play a pivotal role in modulating CV disease development. For example, recent evidence linking processed (but not unprocessed) meats to increased CV risk pointed to the gut microbial metabolite trimethylamine N-oxide as a potential culprit. In addition, altered gut microbiota could also mediate the proinflammatory and cardiometabolic abnormalities associated with excess added free sugar consumption, and in particular high-fructose corn syrup. Substantially more research is required, however, to fully understand how and which alterations in gut flora can prevent or lead to CV disease and other chronic illnesses. We conclude with thoughts about the appropriate role for HIIT in CV training and future research in the role of gut flora-directed interventions in CV prevention.

Breathing helium-hyperoxia and tolerance of partitioned exercise in patients with COPD

PURPOSE

Partitioning exercise by 1-legged cycling is more effective than conventional training in patients with chronic obstructive pulmonary disease. Similarly, inhaling helium-hyperoxia can extend conventional exercise tolerance. This study aimed to determine whether breathing helium-hyperoxia could increase the tolerance of a high-intensity exercise session achieved by 1-legged cycling.

METHODS

Participants completed 2 high-intensity, constant power, 1-legged cycle tests to intolerance (tlimit). In a randomized order, they inspired 40% oxygen with the balance helium via mask and 1-way valve, 1-legged helium-hyperoxia (1L-HH), or room air with supplemental oxygen via a nasal cannula, 1-legged nitrogen-hyperoxia (1L-NH). We assessed quadriceps fatigue from the change in maximal voluntary contraction (FMVC) and transcutaneously stimulated twitch force (Ftwitch).

RESULTS

Fifteen participants (forced expiratory volume in 1 second [SD] = 36 [18]% predicted; forced expiratory volume in 1 second/forced vital capacity = 34 [14]%; peak oxygen uptake = 12.8 [2.9] mL · kg · min) completed the study. Self-reported "leg fatigue" was a reason for stopping 25 of 30 tests. There was no significant difference in tlimit (0.2 [-1.4 to 1.8] min) between 1L-HH (12.2 [5.2] min) and 1L-NH (12.0 [4.1] min), or in FMVC measured shortly after HH and NH tests (P= .09). The Ftwitch was less after exercise (P< .05) in both conditions, without a difference between conditions (P= .46).

CONCLUSIONS

Inspiring a helium-hyperoxia mixture does not increase the endurance of what would be a typical training session, breathing supplemental oxygen, of high-intensity 1-legged constant power exercise. Leg muscle fatigue was similar after 1-legged exercise with and without breathing the helium mixture.

Should all patients with COPD be exercise trained?

Exercise training is one of the most powerful interventions to provide symptomatic relief in patients with chronic obstructive pulmonary disease (COPD). The purpose of this minireview is to discuss how exercise training can improve limb muscle dysfunction in this disease. Various exercise training strategies will be outlined, along with their beneficial effects and potential limitations. Strategies to optimize the gains achievable with exercise training will be presented. Whether exercise training may exert deleterious effects in some patients will also be discussed.

Pulmonary rehabilitation: a review of the recent literature

Pulmonary rehabilitation (PR) is an evidence-based, multidisciplinary, comprehensive intervention that can be integrated into the management of individuals with chronic lung disease. It aims to reduce symptoms, optimize function, increase participation in daily life, and reduce health-care resource utilization. In this review, we summarize the new developments in PR over the past 5 years. Issues related to patient assessment include a comparison of cycle- and walking-based measures of exercise capacity, the emergence of multidimensional indices, the refinement of the minimal clinically important difference, and the importance of assessing physical activity. Issues related to exercise training focus on strategies to optimize the training load. We also comment on the acquisition of self-management skills, balance training, optimizing access, and maintaining gains following completion of PR.

Determinação do limiar anaeróbio pela variabilidade da frequência cardíaca de pacientes com DPOC durante exercício em cicloergômetro

INTRODUÇÃO: A Doença Pulmonar Obstrutiva Crônica (DPOC) é caracterizada por alterações estruturais do parênquima pulmonar, acarretando manifestações sistêmicas. Além disso, esses pacientes podem apresentar marcada alteração do controle autonômico cardíaco. Nesse contexto, estudos investigando a variabilidade da frequência cardíaca (VFC) em pacientes com DPOC durante a realização de exercício físico em cicloergometro têm sido pouco explorados. OBJETIVO: Determinar o limiar anaeróbio por meio da VFC com o propósito de estabelecer parâmetros de avaliação e prescrição da intensidade de exercício desses pacientes em cicloergômetro. MATERIAIS E MÉTODOS: Foram avaliados oito pacientes do sexo masculino com diagnóstico de DPOC com idade média de 69,5 ± 7,6 anos. A frequência cardíaca foi analisada no repouso e em diferentes intensidades do exercício. O teste foi realizado em um cicloergômetro e consistiu em um período de aquecimento de quatro minutos em uma potência mínima. Foram, também, realizados degraus com potência inicial de 4W, com acréscimos de 5 em 5W, até que o paciente atingisse o limiar anaeróbio. RESULTADOS: Os pacientes que apresentaram maiores valores de VEF1 apresentaram maiores potências no cicloergômetro. Houve redução significativa da VFC durante o exercício físico se comparado ao repouso sentado p < 0,05. CONCLUSÃO: Os pacientes estudados apresentaram um severo descondicionamento físico reafirmado pela impossibilidade determinada pelo LA de 50% da amostra.