Pulmonary and respiratory muscle function in response to marathon and ultra-marathon running: a review.

The physiological demands of marathon and ultra-marathon running are substantial, affecting multiple body systems. There have been several reviews on the physiological contraindications of participation; nevertheless, the respiratory implications have received relatively little attention. This paper provides an up-to-date review of the literature pertaining to acute pulmonary and respiratory muscle responses to marathon and ultra-marathon running. Pulmonary function was most commonly assessed using spirometry, with infrequent use of techniques including single-breath rebreathe and whole-body plethysmography. All studies observed statistically significant post-race reductions in one-or-more metrics of pulmonary function, with or without evidence of airway obstruction. Nevertheless, an independent analysis revealed that post-race values rarely fell below the lower-limit of normal and are unlikely, therefore, to be clinically significant. This highlights the virtue of healthy baseline parameters prior to competition and, although speculative, there may be more potent clinical manifestations in individuals with below-average baseline function, or those with pre-existing respiratory disorders (e.g., asthma). Respiratory muscle fatigue was most commonly assessed indirectly using maximal static mouth-pressure manoeuvres, and respiratory muscle endurance via maximum voluntary ventilation (MVV12). Objective nerve-stimulation data from one study, and others documenting the time-course of recovery, implicate peripheral neuromuscular factors as the mechanism underpinning such fatigue. Evidence of respiratory muscle fatigue was more prevalent following marathon compared to ultra-marathon, and might be a factor of work rate, and thus exercise ventilation, which is tempered during longer races. Potential implications of respiratory muscle fatigue on health and marathon/ultra-marathon performance have been discussed, and include a diminished postural stability that may increase the risk of injury when running on challenging terrain, and possible respiratory muscle fatigue-induced effects on locomotor limb blood flow. This review provides novel insights that might influence marathon/ultra-marathon preparation strategies, as well as inform medical best-practice of personnel supporting such events

Respiratory mechanics during upper body exercise in healthy humans

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe physiological responses to upper-body exercise (UBE) are well established. Few published studies, however, have attempted to elucidate the mechanical ventilatory responses to UBE. There is empirical evidence that respiratory function may be compromised by UBE during which the ventilatory and postural functions of the ‘respiratory’ muscles may be exacerbated. Therefore, the aims of this thesis were: 1) to characterise the mechanical-ventilatory responses to UBE in healthy subjects; 2) to explore the putative mechanisms that underpin the respiratory responses to UBE; and 3) to assess whether the mechanical-ventilatory stress imposed by UBE induces contractile fatigue of the respiratory muscles. Compared to lower-body exercise (LBE; leg cycling) at ventilation-matched work rates, UBE (arm-cranking) resulted in constraint of tidal volume, higher respiratory frequency, and greater neural drive to the respiratory muscles. Furthermore, end-expiratory lung volume was significantly elevated during peak UBE compared to LBE (39 ± 8 vs. 29 ± 8% vital capacity, p 0.05). In conclusion, mechanical-ventilatory function may be compromised during UBE due to complex interactions between thoracic muscle recruitment, central neural drive and thoracic volume displacement. This thesis presents novel findings which may have important functional implications for clinical populations who report breathlessness during activities of daily living that involve the upper-body, as well a

Running away from the taskscape : ultramarathon as ‘dark ecology’

Drawing on reflections from a collaborative autoethnography, this article argues that ultramarathon running is defied by a 'dark' ecological sensibility (Morton 2007, 2010, 2016), characterised by moments of pain, disgust, and the macabre. In contrast to existing accounts, we problematise the notion that runners 'use' nature for escape and/or competition, while questioning the aesthetic-causal relationships often evinced within these accounts. With specific reference to the discursive, embodied, spatial and temporal aspects of the sport, we explore the way in which participants begin to appreciate the immense power of nature, while being humbled by the fragile and unstable foundations of human experience. Accordingly this article contributes novel insights into the human-nature complex that seek to move beyond Romantic analyses towards a more sophisticated understanding of the relationships between (nature) sport, people and place

Influence of upper-body exercise on the fatigability of human respiratory muscles

PURPOSE: Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. METHODS: Seven healthy men (mean±SD: age 24±4 y; peak O2 uptake [V[Combining Dot Above]O2 peak] 31.9±5.3 ml/kg/min) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas-exchange threshold and V[Combining Dot Above]O2 peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to post-exercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. RESULTS: Exercise time was 24.5±5.8 min for heavy exercise and 9.8±1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73±20 L/min (39±11% maximum voluntary ventilation [MVV]) and 99±19 L/min (53±11% MVV) for severe exercise. Mean Pdi,tw did not differ pre- to post-exercise at either intensity (p>0.05). Immediately (5-15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41±13 vs. 53±15 cmH2O, p<0.05), with the difference no longer significant after 25-35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. CONCLUSIONS: High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (non-respiratory) loading of the thorax.This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 American College of Sports Medicin

Running Away From the Taskscape: Ultramarathon as 'Dark Ecology'

Drawing on reflections from a collaborative autoethnography, this article argues that ultramarathon running is defied by a 'dark' ecological sensibility (Morton 2007, 2010, 2016), characterised by moments of pain, disgust, and the macabre. In contrast to existing accounts, we problematise the notion that runners 'use' nature for escape and/or competition, while questioning the aesthetic-causal relationships often evinced within these accounts. With specific reference to the discursive, embodied, spatial and temporal aspects of the sport, we explore the way in which participants begin to appreciate the immense power of nature, while being humbled by the fragile and unstable foundations of human experience. Accordingly this article contributes novel insights into the human-nature complex that seek to move beyond Romantic analyses towards a more sophisticated understanding of the relationships between (nature) sport, people and place

Lung function responses to cold water ingestion: A randomised controlled crossover trial

This study tested the hypothesis that cold water ingestion would reduce lung function and thereby confound its measurement in a way that is mediated by both temperature and volume. In a randomised crossover trial, 10 healthy adults performed spirometry before and 5, 10, 15, and 30-minutes after consuming one-of-four drinks: 500 mL or 1000 mL refrigerated water (∼2 °C); identical water volumes at ambient temperature (∼18 °C). Ingesting 1000 mL cold water significantly reduced forced vital capacity (FVC) for at least 10 min (mean difference =0.28 L, p < 0.05, d=1.19) and forced expiratory volume in 1 s (FEV1) for at least 15 min (0.20–0.30 L, p < 0.05, d=1.01). Ingesting 500 mL cold water reduced FEV1 for 5 min (0.09 L, p < 0.05, d=1.05). Room-temperature water had no influence on lung function. To avoid confounding the measurement of lung function, we conclude that individuals should avoid drinking cold water, especially in large volumes, immediately prior to a given test

Exercise-induced diaphragm fatigue in a Paralympic champion rower with spinal cord injury

Introduction. The aim of this case report was to determine whether maximal upper-body exercise was sufficient to induce diaphragm fatigue in a Paralympic champion adaptive rower with low-lesion spinal cord injury (SCI). Case Presentation. An elite arms-only oarsman (age 28 y, stature 1.89 m, mass 90.4 kg) with motor-complete SCI (T12) performed a 1000 m time-trial on an adapted rowing ergometer. Exercise measurements comprised pulmonary ventilation and gas exchange, diaphragm EMG-derived indices of neural respiratory drive and intrathoracic pressure-derived indices of respiratory mechanics. Diaphragm fatigue was assessed by measuring pre- to post-exercise changes in the twitch transdiaphragmatic pressure (Pdi,tw) response to anterolateral magnetic stimulation of the phrenic nerves. The time-trial (248 ± 25 W, 3.9 min) elicited a peak O2 uptake of 3.46 L·min−1 and a peak pulmonary ventilation of 150 L·min−1 (57% MVV). Breath-to-stroke ratio was 1:1 during the initial 400 m and 2:1 thereafter. The ratio of inspiratory transdiaphragmatic pressure to diaphragm EMG (neuromuscular efficiency) fell from rest to 600 m (16.0 vs. 3.0). Potentiated Pdi,tw was substantially reduced (−33%) at 15-20 min post-exercise, with only partial recovery (−12%) at 30-35 min. Conclusions. This is the first report of exercise-induced diaphragm fatigue in SCI. The decrease in diaphragm neuromuscular efficiency during exercise suggests that the fatigue was partly due to factors independent of ventilation (e.g., posture and locomotion)

Airflow dynamics and exhaled-breath temperature following cold-water ingestion

Introduction. Drinking cold water evokes decreases in spirometric indices of lung function. We studied whether this could be explained by changes in exhaled-breath temperature (EBT), airflow dynamics,and spirometer measurement sensitivity. Methods. In a randomized/crossover design, 10 healthy adults consumed 1,000 mL refrigerated water (2.1±0.64 ºC) or water at room temperature (19.4±0.5 ºC), with EBT assessed at baseline and at 5,10,15 and 30-min post-ingestion. The influence of EBT on pneumotachograph measurement characteristics was modelled using computational fluid dynamics (CFD). Results. At 5-min post-ingestion, EBT was lower (p<0.001) following the ingestion of cold water versus water at room-temperature (31.7±1.1 vs. 33.0±0.9 °C), and remained lower until 30-min post-ingestion. At a flow of 8 L*s−1 , a decrease in EBT of 2.1 ° 29 C (observed following cold-water ingestion) was modelled to underpredict lung volume by 0.7%. Conclusions. Cold water reduces EBT below baseline but effects pneumotachograph measurements only negligibly; thus, decreased lung function following cold-water ingestion likely has a physiological explanation which warrants further stud

Effect of spirometry on intra-thoracic pressures

Due to the high intra-thoracic pressures associated with forced vital capacity manoeuvres, spirometry is contraindicated for vulnerable patients. However, the typical pressure response to spirometry has not been reported. Eight healthy, recreationally-active men performed spirometry while oesophageal pressure was recorded using a latex balloon-tipped catheter. Peak oesophageal pressure during inspiration was - 47 ± 9 cmH O (37 ± 10% of maximal inspiratory pressure), while peak oesophageal pressure during forced expiration was 102 ± 34 cmH O (75 ± 17% of maximal expiratory pressure). The deleterious consequences of spirometry might be associated with intra-thoracic pressures that approach maximal values during forced expiration

Case-Studies in Physiology: The exercise pressor response to indoor rock climbing

Introduction. This paper assessed the blood pressure, heart rate, and mouth-pressure responses to indoor rock climbing (bouldering) and associated training exercises. Case Presentation. Six well-trained male rock climbers (mean ± SD age = 27.7 ± 4.7 y; stature = 177.7 ± 7.3 cm; mass = 69.8 ± 12.1 kg) completed two boulder problems (6b and 7a+ on the Fontainebleau Scale) and three typical training exercises (Maximum voluntary contraction [MVC] isometric pull-up, 80% MVC pull-ups to fatigue, campus-board to fatigue). Blood pressure and heart rate were measured via an indwelling femoral arterial catheter, and mouth pressure via a mouthpiece manometer. Bouldering evoked a peak systolic pressure of 200 ± 17 mmHg (44 ± 21% increase from baseline), diastolic pressure of 142 ± 26 mmHg (70 ± 32% increase), mean arterial pressure of 163 ± 18 mmHg (56 ± 25% increase), and heart rate of 157 ± 20 b⸱min−1 (81 ± 30% increase). The highest systolic pressure was observed during the campus-board exercise (218 ± 33 mmHg), although individual values as high as 273/189 mmHg were recorded. Peak mouth pressure during climbing was 31 ± 46 mmHg, and this increased independent of climb difficulty. Conclusions. Indoor rock climbing and associated exercises evoke a substantial pressor response, resulting in high blood pressures that may exceed those observed during other resistance exercises. These findings may inform risk stratification for climbers