Incremental step test in patients with pulmonary hypertension.

Cardiopulmonary exercise testing (CPET) on a treadmill or cycle ergometer provides an integrated assessment of the cardiorespiratory system during exertion and is widely used in clinical practice. An incremental step test (IST) can be an alternative for eliciting maximal exercise responses. Therefore, 20 patients with pre-capillary PH (65% female, 41 ±â€¯15 yrs) randomly performed a symptom-limited CPET on a cycle ergometer and IST. Metabolic, cardiovascular, ventilatory and gas exchange variables were recorded during both tests. There was a greater desaturation and higher V̇O2PEAK in IST compared to CPET. The V̇O2GET, HR PEAK (% pred), ΔV̇E/ΔV̇CO2 and ΔHR/ΔV̇O2 were similar in both IST and CPET. By linear regression analyses, the work performed on IST [W = (mass × 9,8 m/s2 x vertical distance)] was a predictor of peak V̇O2 independent of the gender and age (r2 = 077, p = 0001). In conclusion, IST elicited higher peak cardiopulmonary responses and has a good agreement with known severity markers in patients with pre-capillary PH.

Validation and reproducibility of the Glittre activities of daily living test for individuals with Parkinson's disease. / Validación y reproducibilidad de la prueba Glittre de actividades de la vida diaria en personas con enfermedad de Parkinson.

AIM: To investigate the validity and reproducibility of the Glittre Activities of Daily Living (Glittre-ADL) test for individuals with Parkinson's disease. SUBJECTS AND METHODS: Thirty individuals with Parkinson's disease and 19 healthy individuals (control group) were evaluated. Parkinson's disease group was evaluated by the Unified Parkinson's Disease Rating Scale (UPDRS) and underwent the Glittre-ADL test, six-minute walk test (6MWT) and ten-meter walk test (10mWT). Control group performed the Glittre-ADL test. For the intraobserver analysis, two Glittre-ADL tests were performed. For the interobserver analysis, the Glittre-ADL test was repeated on a different day by a second examiner. RESULTS: The Glittre-ADL test was significantly correlated with UPDRS Section II, Section III, and total score. The Glittre-ADL test was inversely correlated with the 6MWT and positively correlated with the 10mWT. The time required to perform the Glittre-ADL test was shorter on the retest in the intraobserver analysis and in the interobserver analysis. The mean difference between the first and second tests, the standard error of measurement and minimum detectable change in minutes were 0.40, 0.08 and 0.24, respectively, for intraobserver, and 0.40, 0.22 and 0.62, for interobserver. CONCLUSION: The Glittre-ADL test is valid and reproducible to evaluate functional capacity in individuals with Parkinson's disease.

TITLE: Validación y reproducibilidad de la prueba Glittre de actividades de la vida diaria en personas con enfermedad de Parkinson.Objetivo. Investigar la validez y la reproducibilidad de la prueba Glittre de actividades de la vida diaria (AVD-Glittre) para personas con enfermedad de Parkinson. Sujetos y métodos. Se evaluó a 30 pacientes con enfermedad de Parkinson y 19 sujetos sanos (grupo de control). El grupo con enfermedad de Parkinson fue evaluado con la Unified Parkinson's Disease Rating Scale (UPDRS) y sometido a la prueba AVD-Glittre, la prueba de marcha de seis minutos (6MWT) y la prueba de marcha de 10 metros (10mWT). El grupo de control realizó la prueba AVD-Glittre. Para el análisis intraobservador se realizaron dos pruebas AVD-Glittre, y para el análisis interobservador, la prueba se repitió otro día con un segundo examinador. Resultados. La prueba AVD-Glittre se correlacionó significativamente con la sección II, la sección III y la puntuación total de la UPDRS. Se correlacionó inversamente con la 6MWT y positivamente con la 10mWT. El tiempo requerido para realizar la prueba AVD-Glittre fue más corto en la nueva prueba en el análisis intraobservador y en el análisis interobservador. La diferencia de medias entre la primera y la segunda pruebas, el error estándar de medición y el cambio mínimo detectable en minutos fueron 0,40, 0,08 y 0,24, respectivamente, para el análisis intraobservador, y 0,40, 0,22 y 0,62, respectivamente, para el análisis interobservador. Conclusión. La prueba AVD-Glittre es válida y reproducible para evaluar la capacidad funcional en personas con enfermedad de Parkinson.

Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise.

We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ) of oxygen consumption (VO(2)) and the applied power output (work rate = WR) during ramp-incremental exercise in patients with mitochondrial myopathy (MM). Fourteen patients (7 males, age 35.4 ± 10.8 years) with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years) took a ramp-incremental cycle ergometer test for the determination of the VO(2) on-exercise mean response time (MRT) and the gas exchange threshold (GET). The ΔVO(2)/ΔWR slope was calculated up to GET (S(1)), above GET (S(2)) and over the entire linear portion of the response (S(T)). Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak VO(2) and muscle performance were lower in patients than controls (P < 0.05). Patients had significantly lower ΔVO(2)/ΔWR than controls, especially the S(2) component (6.8 ± 1.5 vs 10.3 ± 0.6 mL·min(-1)·W(-1), respectively; P < 0.001). There were significant relationships between ΔVO(2)/ΔWR (S(T)) and muscle endurance, MRT-VO(2), GET and peak VO(2) in MM patients (P < 0.05). In fact, all patients with ΔVO(2)/ΔWR below 8 mL·min(-1)·W(-1) had severely reduced peak VO(2) values (<60% predicted). Moreover, patients with higher cardiopulmonary stresses during exercise (e.g., higher Δ ventilation/carbon dioxide output and Δ heart rate/ΔVO(2)) had lower ΔVO(2)/ΔWR (P < 0.05). In conclusion, a readily available, effort-independent index of aerobic dysfunction during dynamic exercise (ΔVO(2)/ΔWR) is typically reduced in patients with MM, being related to increased functional impairment and higher cardiopulmonary stress.

Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise

We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ) of oxygen consumption ( VO2) and the applied power output (work rate = WR) during ramp-incremental exercise in patients with mitochondrial myopathy (MM). Fourteen patients (7 males, age 35.4 ± 10.8 years) with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years) took a ramp-incremental cycle ergometer test for the determination of the VO2 on-exercise mean response time (MRT) and the gas exchange threshold (GET). The ΔVO2/ΔWR slope was calculated up to GET (S1), above GET (S2) and over the entire linear portion of the response (S T). Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak VO2 and muscle performance were lower in patients than controls (P < 0.05). Patients had significantly lower ΔVO2/ΔWR than controls, especially the S2 component (6.8 ± 1.5 vs 10.3 ± 0.6 mL·min-1·W-1, respectively; P < 0.001). There were significant relationships between ΔVO2/ΔWR (S T) and muscle endurance, MRT-VO2, GET and peak VO2 in MM patients (P < 0.05). In fact, all patients with ΔVO2/ΔWR below 8 mL·min-1·W-1 had severely reduced peak VO2 values (<60 percent predicted). Moreover, patients with higher cardiopulmonary stresses during exercise (e.g., higher Δ ventilation/carbon dioxide output and Δ heart rate/ΔVO2) had lower ΔVO2/ΔWR (P < 0.05). In conclusion, a readily available, effort-independent index of aerobic dysfunction during dynamic exercise (ΔVO2/ΔWR) is typically reduced in patients with MM, being related to increased functional impairment and higher cardiopulmonary stress.

A step test to assess exercise-related oxygen desaturation in interstitial lung disease.

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'(O(2))). Chronic breathlessness was also determined, as measured by the baseline dyspnoea index (BDI). Responses to 6MST were highly reproducible: 1.3+/-2.0 steps x min(-1), +/-5 beats x min(-1) (cardiac frequency), +/-50 mL x min(-1) (V'(O(2))), +/-7 L x min(-1) (minute ventilation) and +/-2% (arterial oxygen saturation measured by pulse oximetry (S(p,O(2)))). The number of steps climbed in 6 min was correlated to peak V'(O(2)) and the BDI. There were significant associations among the tests in relation to presence (change in S(p,O(2)) between rest and exercise > or = 4%) and severity (S(p,O(2)) <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.

The pattern and timing of breathing during incremental exercise: a normative study.

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 (VT)/resting inspiratory capacity, respiratory frequency, total respiratory time (Ttot), inspiratory time (TI), expiratory time (TE), duty cycle (TI/Ttot) and mean inspiratory flow (VT/TI) were analysed at selected submaximal ventilatory intensities. Senescence and female sex were associated with a more tachypnoeic breathing pattern during isoventilation. The decline in Ttot was proportional to the TI and TE reductions, i.e. TI/Ttot was 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.