Robert W. Gotshall

Exercise-induced bronchoconstriction.

Exercise-induced asthma, or more appropriately, exercise-induced bronchoconstriction (EIB), occurs in 80 to 90% of individuals with asthma and in approximately 11% of the general population without asthma. EIB is characterised by post-exercise airways obstruction resulting in reductions in forced expiratory volume in 1 second (FEV1) of greater than 10% compared with pre-exercise values. The mechanism of EIB remains elusive, although both cooling and drying of airways play prominent roles. Cold, dry inhaled air during exercise or voluntary hyperventilation is the most potent stimulus for EIB. Inflammatory mediators play central roles in causing the post-exercise airways obstruction.Diagnosis of EIB requires the use of an exercise test. The exercise can be a field or laboratory based test, but should be of relatively high intensity (80 to 90% of maximal heart rate) and duration (at lest 5 to 8 minutes). Pre- and post-exercise pulmonary function should be compared, and post exercise pulmonary function determined over 20 to 30 minutes for characterisation of EIB. A pre- to post-exercise drop in FEV1 of greater than 10% is abnormal.Approaches to treatment of EIB include both nonpharmacological and pharmacological strategies. A light exercise warm up prior to moderate to heavy exercise reduces the severity of EIB. More recently, studies have supported a role for dietary salt as a modifier of the severity of EIB, suggesting that salt restrictive diets should reduce symptoms of EIB. Short acting, inhaled β2-agonists constitute the most used prophylactic treatment for EIB. However, antileukotriene agents are emerging as effective, well tolerated, long-term treatments for EIB.

Changes in pulmonary diffusing capacity and closing volume after running a marathon

The purpose of this study was to evaluate changes in lung function after running a marathon. Pulmonary function tests were administered to 8 men before, immediately after, and the day following competition (mean run time = 3 hr 30 min). Subjects completed maximum expiratory flow volume maneuvers breathing air and 80% He/20% O2. Lung volumes were determined by N2 washout and single breath He dilution. Closing volumes (CV) were determined using a single breath O2 test. Pulmonary diffusing capacity (DLCO), pulmonary capillary blood volume (Vc), and membrane diffusing capacity (DM) were measured with the single breath technique. There were no changes in lung volumes or flow rates, except for an increase in FEV1, after the marathon. The He/O2 delta Vmax50, delta Vmax25, and isoflow values were similar pre- compared to post-race. There were significant decreases, however, in DLCO, DM and increases in CV post-race. Vc remained similar to pre-race values. These results suggest that small airways obstruction does not occur after a marathon. The significant increase in alveolar-capillary membrane resistance, however, may reflect the occurrence of subclinical edema. Such a change would decrease lung elastic recoil and could explain the increase in CV.

Dietary salt restriction improves pulmonary function in exercise-induced asthma.

PURPOSE Exercise-induced asthma (EIA) occurs in approximately 90% of persons with asthma. The mechanism has not been delineated. Epidemiological studies have suggested that dietary salt may play a role in airway responsiveness. Therefore, the purpose of this study was to determine the influence of both elevated and restricted salt diets on pulmonary function in subjects with EIA. METHODS Eight subjects with EIA and eight subjects without EIA (control) participated in a double-blind crossover study. Pulmonary function was determined pre- and post-exercise challenge before and after 2 wk on a normal salt, sodium chloride, diet (NSD), a low salt diet (LSD), and a high salt diet (HSD). A 1-wk washout occurred between diets. RESULTS Diet had no effect on preexercise pulmonary function values in either group and had no effect on postexercise pulmonary function values in control subjects. However, LSD improved and HSD worsened postexercise pulmonary function values in EIA subjects. Forced expiratory volume in 1 s (FEV1) decreased by at least 10% in EIA subjects with exercise. In EIA subjects, FEV1 decreased by 14+/-6% on LSD, 20+/-7% on NSD, and 24+/-6% on HSD at 15 min postexercise. Similar patterns were observed for forced vital capacity and peak expiratory flow rates. Although LSD did not normalize pulmonary function in EIA, it did improve it. CONCLUSIONS These data suggest that individuals with EIA might benefit from lower salt diets.

Pulmonary function changes in wheelchair athletes subsequent to exercise training

The purpose of this investigation was to determine the pulmonary function and aerobic fitness of wheelchair athletes and assess changes in these values subsequent to an upper-body interval training programme (ITP). Eight male members of the United States national collegiate champion wheelchair basketball team were tested prior to and after an 8 week ITP. Each subject trained (30 min; 3 times per week) on a wheelchair ergometer (WERG) at a power output which would elicit 80% of maximum HR reserve. Before and after training, measurements were obtained at rest, during WERG exercise at 10,20 and 30 W, and during maximal exercise. Static lung volumes and timed forced expiratory volumes measured by spirometry were unchanged by training. Submaximal exercise pulmonary ventilation and oxygen uptake values were similar before and after training, but maximal exercise ventilation (KEmax) increased from 100 to 1311 min−1. In addition, the ratio of KEmax to maximum voluntary ventilation (12s) increased significantly fr...

Central and peripheral hemodynamics during maximal leg extension exercise

SummaryThe purpose of this study was to examine the central and peripheral hemodynamic adaptations to maximal leg extension exercise. Seventeen men (¯X=25 years, 84 kg) performed leg extension exercise (Universal equipment) for 12 repetitions (90s) to fatigue. Each repetition consisted of a 3s lifting motion, 1s pause, and 3s lowering motion. Impedance cardiography was used to measure stroke volume (SV), cardiac output (

Dietary salt alters pulmonary function during exercise in exercise-induced asthmatics

\dot V_{{\text{O}}_{{\text{2 max}}} }

Polymerized bovine hemoglobin decreases oxygen delivery during normoxia and acute hypoxia in the rat.

), systolic time intervals, and impedance contractility indices on a beat-by-beat basis. There were significant increases in systolic, diastolic, mean arterial pressure, total peripheral resistance, and HR during exercise. The mean