Prescribing cycle training intensity from the six-minute walk test for patients with COPD

Background: Cycle training intensity for patients with chronic obstructive pulmonary disease (COPD) is normally based on an incremental cycle test. Such tests are expensive and not readily available to clinicians. The six-minute walk test (6MWT) has been proposed as an alternative to an incremental cycle test for this purpose, based on the findings of previous research that the peak oxygen consumption (VO2peak) for the incremental cycle test and the 6MWT was equivalent in participants with COPD. A regression equation relating distance walked on the 6MWT and peak work rate (Wpeak) on the incremental cycle test has been described. The aim of this study is to measure the physiological responses to constant load cycle exercise performed at an intensity of 60% Wpeak determined from the 6MWT in participants with stable COPD. Methods/Design: This study is a prospective, repeated measures design. Thirty-five participants with stable COPD and mild to severe lung disease will be recruited from referrals to pulmonary rehabilitation. Subjects with co-morbidities limiting exercise performance will be excluded. Two 6MWTs will be performed. The better 6MWT will be used to calculate Wpeak for cycle exercise from a regression equation. After 30 minutes rest, subjects will perform ten minutes of constantload cycle exercise at 60% of the calculated Wpeak. During all exercise, cardiorespiratory and metabolic data (Cosmed K4b2), dyspnoea and rate of perceived exertion (RPE) will be recorded. The VO2 measured at the end of cycle exercise will be compared to VO2peak of the 6MWT (VO2bike/ VO2walk). Pearson's correlation coefficient will be calculated for the relationship between VO2bike and VO2walk. A one-way analysis of variance (ANOVA), with Bonferroni correction, will be performed to determine whether the ratio of VO2bike/VO2walk is affected by disease severity. Discussion: This novel study will measure the physiological responses to cycle exercise, in terms of VO2peak, performed at an intensity determined from the 6MWT in participants with COPD. Positive findings will enable clinicians to more precisely prescribe cycle training intensity by utilising a simple, reliable and inexpensive 6MWT, thus providing a better standard of care for patients with COPD referred to pulmonary rehabilitation

Greater exercise tolerance in COPD during acute interval, compared to equivalent constant‐load, cycle exercise: physiological mechanisms

The relative importance of ventilatory, circulatory and peripheral muscle factors in determining tolerance to exercise in patients with COPD is not known. In twelve COPD patients (FEV1 :58 ± 17%pred.) we measured ventilation, cardiac output, dynamic hyperinflation, local muscle oxygenation, blood lactate and time to exhaustion during a) interval exercise (IE) consisting of 30 s at 100% peak work-rate alternated with 30 s at 50% and b) constant load exercise (CLE) at 75% WRpeak, designed to produce the same average work rate. Exercise time was substantially longer during IE than CLE (19.5 ± 4.8 versus 11.4 ± 2.1 min, p = 0.0001). Total work output was therefore greater during IE than CLE (81.3 ± 27.7 versus 48.9 ± 23.8 kJ, p = 0.0001). Dynamic hyperinflation (assessed by changes from baseline in inspiratory capacity-ΔIC) was less during IE than CLE at CLE exhaustion time (isotime, p = 0.009), but was similar at exhaustion (ΔICCLE : -0.38 ± 0.10 versus ΔICIE : -0.33 ± 0.12 l, p = 0.102). In contrast, at isotime, minute ventilation, cardiac output and systemic oxygen delivery did not differ between protocols (p>0.05). At exhaustion in both protocols, vastus lateralis and intercostal muscle oxygen saturation were higher in IE than CLE (p = 0.014 and p = 0.0002, respectively) and blood lactate concentrations were lower (4.9 ± 2.4 mmol/l versus 6.4 ± 2.2 mmol/l, p = 0.039). These results suggest that 1) exercise tolerance in COPD is limited by dynamic hyperinflation; and 2) cyclically lower (50%) effort intervals in IE help preserve muscle oxygenation and reduce metabolic acidosis compared to CLE at the same average work rate, but these factors do not appear to determine time to exhaustion

Nutrient content in selected commercial rice in Malaysia: An update of Malaysian food composition database

Abstract There is an increase need and demand to update Malaysian Food Composition Database (FCD) which was last updated in 1997. The current FCD program was designed to expand the quantity and improve the quality of the existing database. The present work was aimed to determine the nutrient content of commercial rice products from three rice varieties classified as raw and processed foods, namely Basmati, Siam, and Fragrant rice. A total of six brands from each type of rice were sampled from a local supermarket within Klang Valley. Analyses were carried out for 27 nutrients that include proximate (Energy, Water, Protein, Fat, Carbohydrate, Total Dietary Fibre, and Ash), minerals (Magnesium, Calcium, Sodium, Iron, Zinc, and Copper), water soluble vitamins (C, B1, B2, B3, B6 and B9), fat soluble vitamins (A and E), total sugar, fatty acids (total saturated fat, total monounsaturated fat and total polyunsaturated), trans fatty acids, and cholesterol. The three rice varieties were found to contain comparable nutrient levels except for vitamin C, B1, A, E and total sugar which were not detected in all samples. The fatty acid (total saturated, total monounsaturated, and total polyunsaturated) as well as transfatty acid were detected at very low levels. Cholesterol was not detected in all samples. These findings can be utilised in raising public awareness and assistance to better estimate nutrient contents and intake depending on the varieties of rice

Patients admitted with an acute exacerbation of chronic obstructive pulmonary disease had positive experiences exercising from the beginning of their hospital stay

The aim of the study is to explore the experiences of inpatients with an acute exacerbation of chronic obstructive pulmonary disease, who participated in a very early exercise programme while acutely unwell. This qualitative study analysed responses from participant interviews as part of a mixed method trial whereby participants were randomly allocated into three groups: low intensity, moderate to high intensity aerobic and resistance exercises or a control group who received routine physiotherapy. Everyone allocated to the exercise groups were invited to participate in the qualitative study. Interviews were within a week post discharge and the results were analysed thematically. A total of 19 participants were interviewed and described their experience as positive and beneficial and reported an increased motivation towards exercising. These findings converged with the high levels of exercise adherence (83%) and within-group improvements in walking capacity observed in both exercise groups. Participants also reported commencement of a home exercise programme after discharge but intention to participate in community pulmonary rehabilitation remained low. Participation in a very early exercise programme while acutely unwell can lead to positive attitude towards exercise. The results converge with the quantitative results that provided preliminary evidence of programme feasibility and within-group improvement in exercise tolerance