The effect of inspiratory muscle training on respiratory and limb locomotor muscle deoxygenation during exercise with resistive inspiratory loading.

We investigated how inspiratory muscle training impacted respiratory and locomotor muscle deoxygenation during submaximal exercise with resistive inspiratory loading. 16 male cyclists completed 6 weeks of either true (n=8) or sham (n=8) inspiratory muscle training. Pre- and post-training, subjects completed 3, 6-min experimental trials performed at ~80%  ˙VO2peak with interventions of either moderate inspiratory loading, heavy inspiratory loading, or maximal exercise imposed in the final 3 min. Locomotor and respiratory muscle oxy-, deoxy-, and total-haemoglobin and myoglobin concentration was continuously monitored using near-infrared spectroscopy. Locomotor muscle deoxygenation changes from 80%  ˙VO2peak to heavy inspiratory loading were significantly reduced pre- to post-training from 4.3±5.6 µM to 2.7±4.7 µM. Respiratory muscle deoxygenation was also significantly reduced during the heavy inspiratory loading trial (4.6±3.5 µM to 1.9±1.5 µM) post-training. There was no significant difference in oxy-, deoxy-, or total-haemoglobin and myoglobin during any of the other loading trials, from pre- to post-training, in either group. After inspiratory muscle training, highly-trained cyclists exhibited decreased locomotor and respiratory muscle deoxygenation during exercise with heavy inspiratory loading. These data suggest that inspiratory muscle training reduces oxygen extraction by the active respiratory and limb muscles, which may reflect changes in respiratory and locomotor muscle oxygen delivery

Randomized Controlled Trial of Fish Oil and Montelukast and Their Combination on Airway Inflammation and Hyperpnea-Induced Bronchoconstriction

Both fish oil and montelukast have been shown to reduce the severity of exercise-induced bronchoconstriction (EIB). The purpose of this study was to compare the effects of fish oil and montelukast, alone and in combination, on airway inflammation and bronchoconstriction induced by eucapnic voluntary hyperpnea (EVH) in asthmatics. In this model of EIB, twenty asthmatic subjects with documented hyperpnea-induced bronchoconstriction (HIB) entered a randomized double-blind trial. All subjects entered on their usual diet (pre-treatment, n = 20) and then were randomly assigned to receive either one active 10 mg montelukast tablet and 10 placebo fish oil capsules (n = 10) or one placebo montelukast tablet and 10 active fish oil capsules totaling 3.2 g EPA and 2.0 g DHA (n = 10) taken daily for 3-wk. Thereafter, all subjects (combination treatment; n = 20) underwent another 3-wk treatment period consisting of a 10 mg active montelukast tablet or 10 active fish oil capsules taken daily. While HIB was significantly inhibited (p0.017) between treatment groups; percent fall in forced expiratory volume in 1-sec was −18.4±2.1%, −9.3±2.8%, −11.6±2.8% and −10.8±1.7% on usual diet (pre-treatment), fish oil, montelukast and combination treatment respectively. All three treatments were associated with a significant reduction (p0.017) in these biomarkers between treatments. While fish oil and montelukast are both effective in attenuating airway inflammation and HIB, combining fish oil with montelukast did not confer a greater protective effect than either intervention alone. Fish oil supplementation should be considered as an alternative treatment for EIB

Eucapnic Voluntary Hyperpnea: Gold Standard for Diagnosing Exercise-Induced Bronchoconstriction in Athletes?

In athletes, a secure diagnos is of exercise-induced bronchoconstriction (EIB) is dependent on objective testing. Evaluating spirometric indices of airflow before and following an exercise bout is intuitively the optimal means for the diagnosis; however, this approach is recognized as having several key limitations. Accordingly, alternative indirect bronchoprovocation tests have been recommended as surrogate means for obtaining a diagnosis of EIB. Of these tests, it is often argued that the eucapnic voluntary hyperpnea (EVH) challenge represents the ‘gold standard’. This article provides a state-of-the-art review of EVH, including an overview of the test methodology and its interpretation. We also address the performance of EVH against the other functional and clinical approaches commonly adopted for the diagnosis of EIB. The published evidence supports a key role for EVH in the diagnostic algorithm for EIB testing in athletes. However, its wide sensitivity and specificity and poor repeatability preclude EVH from being termed a ‘gold standard’ test for EIB

Nonpharmacologic Strategies to Manage Exercise-Induced Bronchoconstriction

Pharmacological management of exercise induced bronchoconstriction (EIB) is the mainstay of preventative therapy. However, there are some non-pharmacological interventions that may assist the management of EIB. In this review we will discuss these non-pharmacological interventions and how they may be applied to patients and athletes with EIB

Inspiratory loading and limb locomotor and respiratory muscle deoxygenation during cycling exercise

The aim of this study was to determine the effect of inspiratory loading on limb locomotor (LM) and respiratory muscle (RM) deoxygenation ([deoxy (Hb+Mb)]) using NIRS during constant-power cycling exercise. Sixteen, male cyclists completed three, 6-min trials. The intensity of the first 3-min of each trial was equivalent to ~80% V(O(2max)) (EX(80%)); during the final 3-min, subjects received an intervention consisting of either moderate inspiratory loading (Load(mod)), heavy inspiratory loading (Load(heavy)), or maximal exercise (Load(EX)). Load(heavy) significantly increased LM [deoxy(Hb+Mb)] from 12.2±9.0 μm during EX(80%) to 15.3±11.7 μm, and RM [deoxy(Hb+Mb)] from 5.9±3.6 μm to 9.5±6.6 μm. LM and RM [deoxy(Hb+Mb)] were significantly increased from EX(80%) to Load(EX); 12.8±9.1 μm to 16.4±10.3 μm and 5.9±2.9 μm to 11.0±6.4 μm, respectively. These data suggest an increase in respiratory muscle load increases muscle deoxy(Hb+Mb) and thus may indicate a reduction in oxygen delivery and/or increased oxygen extraction by the active muscles

Inspiratory muscle training lowers the oxygen cost of voluntary hyperpnea

The purpose of this study was to determine if inspiratory muscle training (IMT) alters the oxygen cost of breathing (VO(2RM)) during voluntary hyperpnea. Sixteen male cyclists completed 6 wks of inspiratory muscle training (IMT) using an inspiratory load of 50% (IMT) or 15% [placebo] (CON) of maximal inspiratory pressure (PImax). Prior to training, a maximal incremental cycle ergometer test was performed to determine VO(2) and ventilation (V(E)) at multiple workloads. Pre- and post- training, subjects performed three separate 4-min bouts of voluntary eucapnic hyperpnea (mimic), matching V(E) that occurred at 50%, 75% and 100% of VO(2max). PI(max) was significantly increased (p0.05) were shown in the CON group. IMT significantly reduced the O(2) cost of voluntary hyperpnea, which suggests that a reduction in the O(2) requirement of the respiratory muscles following a period of IMT may facilitate increased O(2) availability to the active muscles during exercise. These data may provide an insight into the mechanism(s) underpinning the reported improvements in endurance performance following IMT, however, this awaits further investigation