A 6-min step test (6MST) may constitute a practical method for routinely assessing effort tolerance and exercise-related oxyhaemoglobin desaturation (ERD) in the primary care of patients with interstitial lung disease.In total, 31 patients (19 males) with idiopathic pulmonary fibrosis (n = 25) and chronic hypersensitivity pneumonia were submitted, on different days, to two 6MSTs. Physiological responses were compared with those found on maximal and submaximal cycle ergometer tests at the same oxygen uptake (V′O₂). Chronic breathlessness was also determined, as measured by the baseline dyspnoea index (BDI).Responses to 6MST were highly reproducible: 1.3±2.0 steps·min^-1, ±5 beats·min^-1(cardiac frequency), ±50 mL·min^-1(V′O₂), ±7 L·min^-1(minute ventilation) and ±2% (arterial oxygen saturation measured by pulse oximetry (Sp,O₂)). The number of steps climbed in 6 min was correlated to peakV′O₂and the BDI. There were significant associations among the tests in relation to presence (change inSp,O₂between rest and exercise ≥4%) and severity (Sp,O₂<88%) of ERD. Four patients, however, presented ERD only in response to 6MST. Resting diffusing capacity of the lung for carbon monoxide and alveolar–arterial oxygen tension difference were the independent predictors of the number of steps climbed.A single-stage, self-paced 6-min step test provided reliable and reproducible estimates of exercise capacity and exercise-related oxyhaemoglobin desaturation in interstitial lung disease patients.

Clinical evaluation of the pattern and timing of breathing during submaximal exercise can be valuable for the identification of the mechanical ventilatory consequences of different disease processes and for assessing the efficacy of certain interventions.Sedentary individuals (60 male/60 female, aged 20–80 yrs) were randomly selected from >8,000 subjects and submitted to ramp incremental cycle ergometry. Tidal volume (V_T)/ resting inspiratory capacity, respiratory frequency, total respiratory time (T_tot), inspiratory time (T_I), expiratory time (T_E), duty cycle (T_I/T_tot) and mean inspiratory flow (V_T/T_I) were analysed at selected submaximal ventilatory intensities.Senescence and female sex were associated with a more tachypnoeic breathing pattern during isoventilation. The decline inT_totwas proportional to theT_IandT_Ereductions,i.e.T_I/T_totwas remarkably constant across age strata, independent of sex. The pattern, but not timing, of breathing was also influenced by weight and height; a set of demographically and anthropometrically based prediction equations are therefore presented.These data provide a frame of reference for assessing the normality of some clinically useful indices of the pattern and timing of breathing during incremental cycle ergometry in sedentary males and females aged 20–80 yrs.

BACKGROUND: Chest wall mobility is often measured in clinical practice, but the correlations between chest wall mobility and respiratory muscle strength and lung volumes are unknown. We investigate the associations between chest wall mobility, axillary and thoracic cirtometry values, respiratory muscle strength (maximum inspiratory pressure and maximum expiratory pressure), and lung volumes (expiratory reserve volume, FEV ₁ , inspiratory capacity, FEV ₁ /FVC), and the determinants of chest mobility in healthy subjects. METHODS: In 64 healthy subjects we measured inspiratory capacity, FVC, FEV ₁ , expiratory reserve volume, maximum inspiratory pressure, and maximum expiratory pressure, and chest wall mobility via axillary and thoracic cirtometry. We used linear regression to evaluate the influence of the measured variables on chest wall mobility. RESULTS: The subjects' mean ± SD values were: age 24 ± 3 years, axillary cirtometry 6.3 ± 2.0 cm, thoracic cirtometry 7.5 ± 2.3 cm; maximum inspiratory pressure 90.4 ± 10.6% of predicted, maximum expiratory pressure 92.8 ± 13.5% of predicted, inspiratory capacity 99.7 ± 8.6% of predicted, FVC 101.9 ± 10.6% of predicted, FEV ₁ 98.2 ± 10.3% of predicted, expiratory reserve volume 90.9 ± 19.9% of predicted. There were significant correlations between axillary cirtometry and FVC (r = 0.32), FEV ₁ (r = 0.30), maximum inspiratory pressure (r = 0.48), maximum expiratory pressure (r = 0.25), and inspiratory capacity (r = 0.24), and between thoracic cirtometry and FVC (r = 0.50), FEV ₁ (r = 0.48), maximum inspiratory pressure (r = 0.46), maximum expiratory pressure (r = 0.37), inspiratory capacity (r = 0.39), and expiratory reserve volume (r = 0.47). In multiple regression analysis the variable that best explained the axillary cirtometry variation was maximum inspiratory pressure (R ² 0.23), and for thoracic cirtometry it was FVC and maximum inspiratory pressure (R ² 0.32). CONCLUSIONS: Chest mobility in healthy subjects is related to respiratory muscle strength and lung function; the higher the axillary cirtometry and thoracic cirtometry values, the greater the maximum inspiratory pressure, maximum expiratory pressure, and lung volumes in healthy subjects.

Os testes do degrau são utilizados para avaliar a capacidade física. Devido à diversidade desses testes, o objetivo desta revisão foi descrever os protocolos utilizados em indivíduos saudáveis e naqueles com doença pulmonar crônica. Os testes do degrau utilizados em indivíduos saudáveis tiveram várias modificações ao longo dos anos. Na maioria dos testes, a duração é variável (90 s-10 min), mas a altura do degrau (23,0-50,8 cm) e o ritmo (22,5-35,0 degraus/min) permanecem constantes durante todo o teste. Entretanto, a utilização de uma altura fixa e de ritmo constante pode deixar de promover uma intensidade de trabalho adequada para indivíduos com diferentes níveis de aptidão física, e, portanto, a carga de trabalho pode estar acima ou abaixo da capacidade individual. Dessa forma, os protocolos foram modificados com a introdução de mudanças na altura do degrau e no ritmo durante o teste. Desde o final dos anos 70, os testes do degrau têm sido utilizados em pacientes com doenças pulmonares crônicas. Os protocolos são diversificados, com ajustes na altura do degrau (15-30 cm), ritmo (autocadenciado ou externamente cadenciado) e duração (90 s-10 min). Entretanto, a diversidade desses protocolos e a variedade de desfechos estudados impedem a determinação do melhor protocolo a ser utilizado em indivíduos com doenças pulmonares crônicas. Parece que os protocolos mais curtos com elevado ritmo seriam mais adequados para avaliar a dessaturação de oxigênio relacionada ao exercício na doença pulmonar crônica. Testes limitados por sintomas seriam mais apropriados para avaliar a tolerância ao exercício. São necessários estudos comparando diferentes protocolos de teste do degrau em relação a sua reprodutibilidade, validade e habilidade de quantificar respostas a intervenções, especialmente em indivíduos com doença pulmonar.

BACKGROUND: The 5-stage Chester step test assesses aerobic capacity in healthy subjects. It has not been tested in patients with COPD. OBJECTIVE: To determine the reliability of the Chester step test in patients with COPD and correlation with pulmonary function test and exercise test results. METHODS: Thirty-two patients (mean ± SD FEV₁ 46 ± 15% of predicted) undertook 2 Chester step tests and two 6-min walk tests, on different days, in random order. A subgroup of 11 patients performed incremental cycle ergometry. RESULTS: Thirty-one patients performed stage 1 of the Chester step test. Nineteen patients performed stage 2 of the Chester step test. The number of steps was highly reproducible: 66 ± 41 steps vs 68 ± 41 steps. There was no difference in heart rate or SpO₂ between the 2 Chester step tests at the peak of exercise or at the end of each stage. There was a significant correlation between number of steps and FEV₁ (r = 0.43, P = .02), and 6-min walk distance (r = 0.60, P = .001). Heart rate increased according to advanced stages of the Chester step test, up to 81 ± 13% of predicted. There was a significant correlation between number of steps and peak heart rate (r = 0.55, P = .001). In the 11 patients who performed the incremental cycling test there was a significant correlation between number of steps and peak work load (r = 0.69, P = .02). In the 6 patients in whom oxygen uptake could be estimated from the Chester step test, oxygen uptake was higher than that measured at the peak of the cycling test (30.8 ± 5.1 mL/kg/min vs 17.4 ± 4.5 mL/kg/min, respectively, P = .001). CONCLUSIONS: Despite being highly reproducible, the Chester step test had a very short duration in patients with COPD. The number of steps incremented in each stage seems to be too large for these patients. An adaptation of the Chester step test should be considered for patients with COPD.