Airway response during exercise and hyperpnoea in non-asthmatic and asthmatic individuals

Ozone exposure limits cardiorespiratory function during maximal cycling exercise in endurance athletes

Ground-level ozone (O3) is a potent air pollutant well recognized to acutely induce adverse respiratory symptoms and impairments in pulmonary function. However, it is unclear how the hyperpnea of exercise may modulate these effects, and the subsequent consequences on exercise performance. We tested the hypothesis that pulmonary function and exercise capability would be diminished, and symptom development would be increased during peak real-world levels of O3 exposure compared with room air. Twenty aerobically trained participants [13 M, 7 F; maximal O2 uptake (V̇o2max), 64.1 ± 7.0 mL·kg-1·min-1] completed a three-visit double-blinded, randomized crossover trial. Following a screening visit, participants were exposed to 170 ppb O3 or room air (<10 ppb O3) on separate visits during exercise trials, consisting of a 25-min moderate-intensity warmup, 30-min heavy-intensity bout, and a subsequent time-to-exhaustion (TTE) performance test. No differences in O2 uptake or ventilation were observed during submaximal exercise between conditions. During the TTE test, we observed significantly lower end-exercise O2 uptake (-3.2 ± 4.3%, P = 0.004), minute ventilation (-3.2 ± 6.5%, P = 0.043), tidal volume (-3.6 ± 5.1%, P = 0.008), and a trend toward lower exercise duration in O3 compared with room air (-10.8 ± 26.5%, P = 0.092). As decreases in O2 uptake and alterations in respiratory pattern were also present at matched time segments between conditions, a limitation of oxygen transport seems likely during maximal exercise. A more comprehensive understanding of the direct mechanisms that limit oxygen transport during exercise in high-pollutant concentrations is key for mitigating performance changes.NEW & NOTEWORTHY We demonstrate that in highly trained endurance athletes, exposure to peak real-world levels of O3 air pollution (170 ppb) significantly diminishes O2 uptake along with corresponding changes in ventilation during maximal exercise. As no differences were observed during extended submaximal exercise, a combined effect of effective dose of pollution and exercise intensity on severity of responses seems likely.

Exercise induced bronchodilation: a phenomenon more common, greater magnitude and more prolonged in older adults than in adolescents

Objective. There are few studies in clinically healthy subjects describing and quantifying exercise-induced bronchodilation (EIB_d). This study aimed to describe and compare the magnitude and time course changes in post-exercise forced expired volume at the first second (FEV₁) in healthy adolescents, younger adults, and older adults.Methods. Adolescent (n = 73, aged 10-17 yrs), younger adult (n = 35, aged 18-25 yrs) and older adult (n = 25, aged 35-66 yrs) subjects with normal spirometry z-scores completed a maximal cardiopulmonary exercise test using the standardised exponential exercise test protocol on a cycle ergometer performed at stable temperature and humidity. Spirometry was performed pre-exercise and at 1-, 3-, 5-, and 10- minutes post-exercise to determine the percentage change in FEV₁ compared to baseline. EIB_d was defined as a ≥5% increase in post-exercise FEV₁.Results. Increases in FEV₁ at one-minute post-exercise were observed in the adolescents (1.3%) and young adults (6.0%) with FEV₁ returning to baseline after ten minutes. Compared to the adolescents, the older adults showed significantly greater and sustained increases in FEV₁ at 1-, 3-, 5-, and 10- minutes post-exercise (6.4, 4.6, 4.7, and 3.8%, p < 0.05). At 1-minute post exercise a significantly greater proportion of younger adults (54%, p < 0.01) and older adults (64%, p < 0.01) demonstrated EIB_d compared to the adolescent group (15%).Conclusion. Healthy older adults had a higher prevalence, greater magnitude and more prolonged EIB_d compared to healthy adolescent and young adult subjects.

Quantifying tidal expiratory flow limitation using a vector-based analysis technique

Objective. Tidal expiratory flow limitation (EFL_T) is commonly identified by tidal breaths exceeding the forced vital capacity (FVC) loop. This technique, known as the Hyatt method, is limited by the difficulties in defining the FVC and tidal flow-volume (TV) loops. The vector-based analysis (VBA) technique described and piloted in this manuscript identifies and quantifies EFL_Tas tidal breaths that conform to the contour of the FVC loop.Approach. The FVC and TV loops are interpolated to generate uniformly spaced plots. VBA is performed to determine the smallest vector difference between each point on the FVC and TV curves, termed the flow reserve vector (FRV). From the FVC point yielding the lowest FRV, the tangential angles of the FVC and TV segments are recorded. If the TV and FVC loops become parallel, the difference between the tangential angles tends towards zero. We infer EFL_Tas parallel TV and FVC segments where the FRV is < 0.1 and the tangential angle is within ±18 degrees for ≥5% of TV. EFL_Tis quantified by the percent of TV loop fulfilling these criteria. We compared the presence and degree of EFL_Tat rest and during peak exercise using the Hyatt method and our VBA technique in 25 healthy subjects and 20 subjects with moderate-severe airflow obstruction.Main results. Compared to the Hyatt method, our VBA technique reported a significantly lower degree of EFL_Tin healthy subjects during peak exercise, and in obstructed subjects at rest and during peak exercise. In contrast to the Hyatt method, our VBA technique re-classified five subjects (one in the healthy group and four in the obstructed group) as demonstrating EFL_T.Significance.Our VBA technique provides an alternative approach to determine and quantify EFL_Twhich may reduce the overestimation of the degree EFL_Tand more accurately identify subjects experiencing EFL_T.

Changes in pulmonary function and feasibility of portable continuous laryngoscopy during maximal uphill running

Objective

To evaluate changes in pulmonary function and feasibility of portable continuous laryngoscopy during maximal uphill running.

Methods

Healthy volunteers participated in an uphill race. Forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) were obtained before and 5 and 10 min after finishing the race. Capillary blood lactate concentration ([BLa^-]) and Borg score for perceived exertion were registered immediately after the race. One participant wore a portable video-laryngoscope during the race, and the video was assessed for technical performance.

Results

Twenty adult subjects participated with a mean (SD) age of 40.2 (9.7) years. Mean (SD) race duration and post-exercise [BLa^-] was 13.9 (2.3) min and 10.7 (2.1) mmol/L, respectively, and the median (range) Borg score for perceived exertion was 9 (5–10).

Mean percentage change (95% CI) 5 and 10 min post-exercise in FEV₁ were 6.9 (3.7 to 10.2) % and 5.9 (2.7 to 9.0) %, respectively, and in FVC 5.2 (2.3 to 8.1) % and 4.7 (1.6 to 7.9) %, respectively. The recorded video of the larynx was of good quality.

Conclusions

Maximal aerobic field exercise induced bronchodilatation in the majority of the healthy non-asthmatic participants. It is feasible to perform continuous video-laryngoscopy during heavy uphill exercise.

High prevalence of exercise-induced stridor during Parkrun: a cross-sectional field-based evaluation

BACKGROUND AND OBJECTIVE

The differential diagnosis for exercise-associated breathlessness is broad, however, when a young athletic individual presents with respiratory symptoms, they are most often prescribed inhaler therapy for presumed exercise-induced asthma (EIA). The purpose of this study was therefore to use a novel sound-based approach to assessment to evaluate the prevalence of exertional respiratory symptoms and characterise abnormal breathing sounds in a large cohort of recreationally active individuals.

METHODS

Cross-sectional field-based evaluation of individuals completing Parkrun. PHASE 1: Prerace, clinical assessment and baseline spirometry were conducted. At peak exercise and immediately postrace, breathing was monitored continuously using a smartphone. Recordings were analysed retrospectively and coded for signs of the predominant respiratory noise. PHASE 2: A subpopulation that reported symptoms with at least one audible sign of respiratory dysfunction was randomly selected and invited to attend the laboratory on a separate occasion to undergo objective clinical workup to confirm or refute EIA.

RESULTS

Forty-eight participants (22.6%) had at least one audible sign of respiratory dysfunction; inspiratory stridor (9.9%), expiratory wheeze (3.3%), combined stridor+wheeze (3.3%), cough (6.1%). Over one-third of the cohort (38.2%) were classified as symptomatic. Ten individuals attended a follow-up appointment, however, only one had objective evidence of EIA.

CONCLUSIONS

The most common audible sign, detected in approximately 1 in 10 individuals, was inspiratory stridor, a characteristic feature of upper airway closure occurring during exercise. Further work is now required to further validate the precision and feasibility of this diagnostic approach in cohorts reporting exertional breathing difficulty.

IMPULSE OSCILLOMETRY AND SPIROMETRY IN SCHOOLERS SUBMITTED TO THE SIX-MINUTE WALK TEST

OBJECTIVE

To verify repercussions of submaximal exercise testing on respiratory mechanics and pulmonary function in schoolchildren.

METHODS

Cross-sectional study, with children aged 7 to 14 years, who had their respiratory mechanics assessed by impulse oscillometry (IOS), and pulmonary function by spirometry. They performed the six-minute walk test (6MWT), as per the standards by the American Thoracic Society. The 6MWT was performed twice with a 30-minute interval. IOS and spirometry were performed before the first 6MWT (Pre-6MWT) and immediately after the first (Post-6MWT1) and second walking tests (Post-6MWT2). The results in these three phases were compared by analysis of variance for repeated measures (post-hoc Bonferroni test) or by the Friedman's test, with p≤0.05 considered significant.

RESULTS

Twenty-one subjects participated in the study: 53% were males and mean age was 10.9±2.3 years. There were differences between total resistance (R5) and central airway resistance (R20) at the three phases of assessment (p=0.025 and p=0.041, respectively). Post-hoc analysis indicated increase in R5 when Pre-6MWT and Post-6MWT1 were compared (R5=0.540±0.100 versus 0.590±0.150 kPa/L/s, p=0.013; and R20=0.440±0.800 versus 0.470±0.100 kPa/L/s, p=0.038). Forced expiratory flow 25-75% (FEF25-75%) changed over time (p=0.003).

CONCLUSIONS

Repercussions were: increase in central and total airway resistance and reduction of FEF25-75% after 6MWT in schoolchildren, suggesting that greater attention should be given to submaximal tests in children with predisposition to airways alterations.

Dyspnea related to reversibly-binding P2Y12 inhibitors: A review of the pathophysiology, clinical presentation and diagnostics

Dyspnea is a common symptom physiologically associated with strenuous exercise and pathologically reflecting well-known diseases and conditions that are predominantly pulmonary, cardiovascular, and weight-related in origin. Dyspnea improves with appropriate measures that enhance physical performance and treatment of the underlying diseases. Dyspnea is less commonly triggered by other causes such as the environment (e.g., ozone), drugs, and others, some of which do not seem to affect bronchopulmonary function as evidenced by normal results of comprehensive pulmonary function testing. In cardiovascular medicine, dyspnea has recently attracted attention because it has been reported that this symptom occurs more frequently with the administration of the new oral reversibly-binding platelet P2Y12 receptor inhibitors ticagrelor [1-6], cangrelor [7-10], and elinogrel [11]. This paper succinctly addresses the current understanding of the pathophysiology, clinical presentation, and diagnostics of dyspnea, associated either with bronchopulmonary function impairment, as triggered mainly by pulmonary and cardiovascular diseases, or without bronchopulmonary function impairment, as induced by endogenous or external compounds such as drugs in order to provide a context for understanding, recognizing and managing P2Y12 inhibitor-induced dyspnea.

Effects of exercise intensity compared to albuterol in individuals with cystic fibrosis

BACKGROUND

Although exercise is a vital component of the therapy prescribed to individuals with cystic fibrosis (CF), it is not a priority due to a finite amount of treatment time and the view that exercise is not as beneficial as pharmacological treatments by many individuals with CF. We sought to compare the therapeutic benefits of exercise and their prescribed bronchodilator albuterol.

METHODS

CF (n = 14) and healthy (n = 16) subjects completed three visits, a baseline screening with VO2 max test and two treatment visits. On the two treatment visits, subjects completed spirometry and diffusing capacity of the lungs for nitric oxide (DLNO) maneuvers either at baseline, 60, and 110 min post-albuterol administration, or at baseline and the midway point of three separate 15 min exercise bouts at low, moderate and vigorous intensity (25, 50 and 65% of the maximum workload, respectively).

RESULTS

With moderate exercise the increase in DLNO was double (39 ± 8 vs 15  ± 6% change) and the level of bronchodilation similar (23% change) when compared to 110 min post-albuterol in individuals with CF. During exercise FVC became reduced (-309 ± 66 mL with moderate exercise) and the increase in FEV1 was attenuated (103 ± 39 vs 236 ± 58 mL, exercise vs. albuterol) when compared with the response to albuterol in individuals with CF. Epinephrine (EPI) release increased 39, 72 and 144% change with low, moderate and vigorous intensity exercise respectively for individuals with CF, but this increase was blunted when compared to healthy subjects.

CONCLUSION

Our results suggest that moderate intensity exercise is the optimal intensity for individuals with CF, as low intensity exercise increases EPI less than 50% and vigorous intensity exercise is over taxing, such that airflow can be restricted. Although the duration of the beneficial effect is uncertain, exercise can promote greater improvements in gas diffusion and comparable bronchodilation when compared to albuterol.

Exercise induced bronchospasm in physically fit female students of Kerman University and their pulmonary function tests

INTRODUCTION

High prevalence of respiratory symptoms and bronchial hyper-responsiveness has been reported in professionals athletes, particularly in relation to climate and environment. However, the airway response to exercise in active population has been poorly investigated especially in women. The aim of this study was to examine pulmonary function test changes in physically fit female students of Kerman University.

METHODS

Sixty physically fit female students (19 ± 1.12 years old) were randomly selected out of 500 students. Each subject underwent the physical fitness test (Couper test) of the maximal distance running in 12 min. The exercise induced bronchospasm (EIB) symptoms including coughing, wheezing, chest tightness, dyspnea, previously diagnosed asthma and allergy, the use of anti-asthmatics medication and the family history of asthma were recorded using a questionnaire. Pulmonary function tests including; forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), peak expiratory flow (PEF), and maximal expiratory flow at 50% of the FVC (MEF(50)) were measured at rest (baseline), immediately, 5, and 15 min after an exercise test.

RESULT

The result of this study showed that the prevalence of the symptoms of EIB was 40.0%. There was not any significant difference in baseline PFT values between symptomatic and asymptomatic subjects. However, All PFT values of symptomatic subjects were significantly lower than asymptomatic immediately after exercise (p < 0.05 to p < 0.01). In addition, PFT values were significantly reduced in all times intervals for the symptomatic subjects (p < 0.05 to p < 0.01).

CONCLUSION

The results showed a high prevalence of respiratory symptoms and EIB in healthy female students.

Acu-TENS and Postexercise Expiratory Flow Volume in Healthy Subjects

Transcutaneous Electrical Nerve Stimulation over acupoints (Acu-TENS) facilitates recovery of resting heart rate after treadmill exercise in healthy subjects. Its effect on postexercise respiratory indices has not been reported. This study investigates the effect of Acu-TENS on forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) in healthy subjects after a submaximal exercise. Eleven male subjects were invited to the laboratory twice, two weeks apart, to receive in random order either Acu-TENS or Placebo-TENS (no electrical output from the TENS unit) over bilateral Lieque (LU7) and Dingchuan (EX-B1) for 45 minutes, before undergoing exercise following the Bruce protocol. Exercise duration, rate of perceived exertion (RPE), and peak heart rate (PHR) were recorded. Between-group FEV1 and FVC, before, immediately after, at 15, 30, and 45minutes postexercise, were compared. While no between-group differences in PHR, RPE, and FVC were found, Acu-TENS was associated with a longer exercise duration (0.9 min (P = .026)) and a higher percentage increase in FEV1 at 15 and 45 minutes postexercise (3.3 ± 3.7% (P = .013) and 5.1 ± 7.5% (P = .047), resp.) compared to Placebo-TENS. We concluded that Acu-TENS was associated with a higher postexercise FEV1 and a prolongation of submaximal exercise.

Moderate increases in ambient PM2.5 and ozone are associated with lung function decreases in beach lifeguards

OBJECTIVE

Exposure to pollutants would adversely affect lung function of healthy athletes.

METHODS

Pulmonary function was recorded on beach lifeguards at three different times during the day. Daily and average peak pollutant levels were calculated. Linear regression analyses were made comparing lung function changes in response to pollutant levels. A multivariate model was constructed to explain the combined effects of pollutants.

RESULTS

Afternoon forced vital capacity (FVC) and forced expired volume in 1 second (FEV1) decreased significantly compared with morning values and decreased with increasing fine particulates (PM2.5). FEV1/FVC decreased with increasing ozone (O3) levels.

CONCLUSION

The deleterious effect of PM2.5 and O3 were transient and occurred at pollutant levels far below national standards. At low levels of exposure, PM2.5 was associated with reduced lung volumes, while increasing O3 levels were associated with airway obstruction.