The effect of acute magnesium loading on the maximal exercise performance of stable chronic obstructive pulmonary disease patients

OBJECTIVE: The potential influence of magnesium on exercise performance is a subject of increasing interest. Magnesium has been shown to have bronchodilatatory properties in asthma and chronic obstructive pulmonary disease patients. The aim of this study was to investigate the effects of acute magnesium IV loading on the aerobic exercise performance of stable chronic obstructive pulmonary disease patients. METHODS: Twenty male chronic obstructive pulmonary disease patients (66.2 + 8.3 years old, FEV1: 49.3+19.8%) received an IV infusion of 2 g of either magnesium sulfate or saline on two randomly assigned occasions approximately two days apart. Spirometry was performed both before and 45 minutes after the infusions. A symptom-limited incremental maximal cardiopulmonary test was performed on a cycle ergometer at approximately 100 minutes after the end of the infusion. ClinicalTrials.gov: NCT00500864 RESULTS: Magnesium infusion was associated with significant reductions in the functional residual capacity (-0.41 l) and residual volume (-0.47 l), the mean arterial blood pressure (-5.6 mmHg) and the cardiac double product (734.8 mmHg.bpm) at rest. Magnesium treatment led to significant increases in the maximal load reached (+8 w) and the respiratory exchange ratio (0.06) at peak exercise. The subgroup of patients who showed increases in the work load equal to or greater than 5 w also exhibited significantly greater improvements in inspiratory capacity (0.29 l). CONCLUSIONS: The acute IV loading of magnesium promotes a reduction in static lung hyperinflation and improves the exercise performance in stable chronic obstructive pulmonary disease patients. Improvements in respiratory mechanics appear to be responsible for the latter finding.

Strategies for cardiopulmonary exercise testing of pectus excavatum patients: [review]

The purpose of this paper is to provide strategies for cardiopulmonary exercise testing of pectus excavatum patients. Currently, there are no standardized methods for assessing cardiovascular and pulmonary responses in this population; therefore, making comparisons across studies is difficult if not impossible. These strategies are intended for physicians, pulmonary technicians, exercise physiologists, and other healthcare professionals who conduct cardiopulmonary exercise testing on pectus excavatum patients. By using the strategies outlined in this report, comparisons across studies can be made, and the effects of pectus excavatum on cardiopulmonary function can be assessed with greater detail.

The study of the relationship between the angiotensin-converting enzyme gene insertion/deletion polymorphism and the cardiorespiratory fitness / 中华老年医学杂志

Objective To explore the relationship between the angiotensin-converting enzyme(ACE) gene inserton/deletion(I/D) polymorphism and the cardiorespiratory fitness. Methods One hundred twenty six male subjects were recruited and randomized into a physical exercise(n=65) or a control group(n=61).The men in the physical exercise group were trained with mild-moderate intensity physical exercise for 5 years. The men in the control group were advised to make their personal choice whether or not to engage in physical exercise. The cardiorespiratory fitness indices,e.g. aerobic threshold were measured at baseline and annually. The I/D polymorphism in the 16 th intron of ACE gene was analysed by polymerase chain reaction. Results At baseline, the aerobic threshold was (14.4 ? 3.9)ml?min -1?kg -1 in the physical exercise group. After 5-year physical exercise, the aerobic threshold was (16.4 ? 4.1)ml?min -1?kg -1in the physical exercise group. At baseline, the aerobic thresholds was(14.2 ?3.6)ml?min -1?kg -1in the control group. After 5 years, the aerobic threshold was(13.8 ? 3.3)ml?min -1?kg -1in the control group. After 5 year physical exercise, compared with the baseline and the control group, the aerobic threshold increased significantly in the physical exercise group(both,P0.05). Conclusions Regular low to moderate intensity physical exercise can increase aerobic threshold and improve cardiorespiratory fitness. Compared with the subjects with the ACE DD genotypes, the cardiorespiratory fitness can be improved more easily for the subjects with the ACE II,ID genotypes.