Birgitte Hanel

The effect of normoxic or hypobaric hypoxic endurance training on the hypoxic ventilatory response.

Cross-sectional studies in endurance athletes have demonstrated a diminished hypoxic ventilatory response (HVR) compared with mountaineers or sedentary controls. Conversely, short-term altitude acclimatization may increase the HVR. The longitudinal effect of training, either at sea level or altitude, on HVR has not been previously reported. We therefore studied 21 untrained men and women before and after 5 wk of cycle ergometer training at either sea level or 2,500 m. HVR was determined using the steady-state method (16). Minute ventilation (VE) was measured with a Tissot spirometer during the last minute of 5 min breathing room air, 8% and 12% O2, administered in random order. CO2 was added at the mouth in an effort to maintain end-tidal CO2 at baseline levels. Oxyhemoglobin saturation was measured directly from arterial blood with a hemoximeter (OSM 3). HVR was defined as the positive slope of the line relating VE to O2 saturation in l.min-1%-1. One group of subjects trained at sea level at 70% maximal oxygen uptake (VO2max; N = 7). A second group trained at 2,500 m in a hypobaric chamber, at the same relative exercise intensity (i.e., 70% altitude VO2max) or same absolute intensity (same power output) as group 1 (N = 14). Both groups trained on a bicycle ergometer for 45 min.d-1, 5 d.wk-1 for 5 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventilation inhomogeneity in children with primary ciliary dyskinesia

Background The lung clearance index (LCI) derived from the multiple breath inert gas washout (MBW) test reflects global ventilation distribution inhomogeneity. It is more sensitive than forced expiratory volume in 1 s (FEV1) for detecting abnormal airway function and correlates closely with structural lung damage in children with cystic fibrosis, which shares features with primary ciliary dyskinesia (PCD). Normalised phase III slope indices Scond and Sacin reflect function of the small conducting and acinar airways, respectively. The involvement of the peripheral airways assessed by MBW tests has not been previously described in PCD. Methods A cross-sectional MBW study was performed in 27 children and adolescents with verified PCD, all clinically stable and able to perform lung function tests. LCI, Scond (n=23) and Sacin (n=23) were derived from MBW using a mass spectrometer and sulfur hexafluoride as inert marker gas. MBW indices were compared with present age, age at diagnosis and spirometry findings, and were related to published normative values. Results LCI, Scond and Sacin were abnormal in 85%, 96% and 78% of patients with PCD and in 81%, 93% and 79%, respectively, of 13/27 subjects with normal FEV1. LCI and Sacin correlated significantly while Scond did not correlate with any other lung function parameters. None of the lung function measurements correlated with age or age at diagnosis. Conclusions PCD is characterised by marked peripheral airway dysfunction. MBW seems promising in the early detection of lung damage, even in young patients with PCD. The relationship of MBW indices to the outcome of long-term disease and their role in the management of PCD need to be assessed.

Maximal oxygen uptake and work capacity after inspiratory muscle training: A controlled study

The effect of inspiratory muscle training for 10 min twice a day for 27.5 days was evaluated in 20 human subjects, of whom 10 formed a training group and 10 a sham training group. The maximal oxygen uptake (VO2 max), maximal ventilation, breathing frequency during maximal exercise and the distance run in 12 min on a track were determined in addition to resting peak expiratory flow, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), with alveolar oxygen tension (pAO2) during maximal exercise being calculated. Inspiratory muscle training increased maximal inspiratory pressure from 93 (range 38-118) to 110 (65-165) mmHg in the training group (P less than 0.0005), but did not affect VO2 max, ventilation during maximal exercise, peak expiratory flow, FEV1 or FVC. However, breathing frequency during maximal exercise decreased slightly from 56 (44-87) to 53 (38-84) breaths min-1 (P less than 0.05) in the training group only; but the calculated pAO2 did not increase from the pre-training value of 126 (116-132) mmHg. The maximal distance run during 12 min increased similarly in the training and sham training groups by 8% (3-12%) and 6% (2-12%), respectively (P less than 0.01). The results of this study show that inspiratory muscle training resulting in a 32% (0-85%) increase in maximal inspiratory pressure does not change FEV1, FVC, peak expiratory flow, VO2 max or work capacity.

Recovery of pulmonary diffusing capacity after maximal exercise

Pulmonary diffusing capacity (DICO), together with spirometric variables, arterial oxygen tension (paO2) and cardiac output were determined before and at intervals after maximal arm cranking, treadmill running and ergometer rowing. Independent of the type of exercise, D1CO increased immediately post-exercise from a median 13.6 (range 7.3-16.3) to 15.1 (9.3-19.6) mmol min-1 kPa-1 (P < 0.01). However, it decreased to 11.6 (6.9-15.5) mmol min-1 kPa-1 (P < 0.01) after 24 h with cardiac output and paO2 at resting values, and D1CO normalized after 20 h. Thoracic electrical impedance at 2.5 and 100 kHz increased slightly post-exercise, indicating a decrease in thoracic fluid balance, and there were no echocardiographic signs of left ventricular failure at the time of the decrease in D1CO. Also, active muscle (limb) circumference and volume, and an increase in haematocrit from 43.8 (38.0-47.0) to 47.1 (42.7-49.8) (P < 0.01), had normalized at the time of the decrease in D1CO. Vital capacity, forced vital capacity, forced expiratory volume in 1 s, peak and peak mid-expiratory flows did not change. However, total lung capacity increased from 6.8 (5.0-7.6) to 7.0 (5.1-7.8) litres (P < 0.05) immediately after exercise and remained elevated at 6.9 (5.1-8.7) litres (P < 0.05) when a decrease in D1CO was noted. The results demonstrate that independent of the type of maximal exercise, an approximate 15% reduction in D1CO takes place 2-3 h post-exercise, which normalizes during the following day of recovery.

Decrease in pulmonary diffusion capacity after maximal exercise

Oppression of the chest, cough and orthopnea are well known to occur in some athletes after competitions, maybe reflecting an increase in lung water. In order to indicate if lung water increases after maximal exercise we measured pulmonary diffusion capacity before and 2.1 h after a short maximal arm exercise bout in 11 canoeists and showed a decrease of 6.7%. The result may be explained by a calculated 17% increase in alveolar interstitial volume.

The single-breath diffusing capacity of CO and NO in healthy children of European descent.

Rationale The diffusing capacity (DL) of the lung can be divided into two components: the diffusing capacity of the alveolar membrane (Dm) and the pulmonary capillary volume (Vc). DL is traditionally measured using a single-breath method, involving inhalation of carbon monoxide, and a breath hold of 8–10 seconds (DL,CO). This method does not easily allow calculation of Dm and Vc. An alternative single-breath method (DL,CO,NO), involving simultaneous inhalation of carbon monoxide and nitric oxide, and traditionally a shorter breath hold, allows calculation of Dm and Vc and the DL,NO/DL,CO ratio in a single respiratory maneuver. The clinical utility of Dm, Vc, and DL,NO/DL,CO in the pediatric age range is currently unknown but also restricted by lack of reference values. Objectives The aim of this study was to establish reference ranges for the outcomes of DL,CO,NO with a 5 second breath hold, including the calculated outcomes Dm, Vc, and the DL,NO/DL,CO ratio, as well as to establish reference values for the outcomes of the traditional DL,CO method, with a 10 second breath hold in children. Methods DL,CO,NO and DL,CO were measured in healthy children, of European descent, aged 5–17 years using a Jaeger Masterscreen PFT. The data were analyzed using the Generalized Additive Models for Location Scale and Shape (GAMLSS) statistical method. Measurements and Main Results A total of 326 children were eligible for diffusing capacity measurements, resulting in 312 measurements of DL,CO,NO and 297 of DL,CO, respectively. Reference equations were established for the outcomes of DL,CO,NO and DL,CO, including the calculated values: Vc, Dm, and the DL,NO/DL,CO ratio. Conclusion These reference values are based on the largest sample of children to date and may provide a basis for future studies of their clinical utility in differentiating between alterations in the pulmonary circulation and changes in the alveolar membrane in pediatric patients.

New insights into the aspects of pulmonary diffusing capacity in Fontan patients.

BACKGROUND Patients with a functionally univentricular heart, palliated a.m. Fontan, consequently have non-pulsatile pulmonary blood flow and are known to have a reduced pulmonary diffusing capacity. However, the cause of this reduction remains unclear. We aimed to assess the possible determinants in the aetiology of a reduced diffusing capacity and also to assess whether it could be increased. Furthermore, we aimed to search for predictors of a reduced diffusing capacity. MATERIAL AND METHODS A total of 87 Fontan patients (mean age 16.3 ± 7.6 years) performed advanced pulmonary function tests and maximal cycle ergometer tests. A total of 10 Fontan patients and nine matched controls performed a supine pulmonary function test after a supine rest. RESULTS In the sitting pulmonary function test, the mean z-scores were: diffusing capacity, 2.38 ± 1.20; pulmonary capillary blood volume, 2.04 ± 0.80; and alveolar capillary membrane diffusing capacity, 0.14 ± 0.84. In the supine compared with the sitting pulmonary function test, the diffusing capacity increased by 51.7 ± 11.9% in the Fontan group and by 23.3 ± 17.7% in the control group (p < 0.001); moreover, the pulmonary capillary blood volume increased by 48.3 ± 17.4% in the Fontan group and by 20.2 ± 13.9% in the control group (p = 0.001). In a multiple linear regression analysis including the explanatory variables of surgical data and exercise data at rest and peak exercise, the resting cardiac index was an independent predictor of the diffusing capacity (regression coefficient: 0.18, p < 0.001). CONCLUSIONS The pulmonary diffusing capacity was reduced in Fontan patients because of a reduced pulmonary capillary blood volume, whereas the alveolar capillary membrane diffusing capacity was preserved. The diffusing capacity was highly increasable in Fontan patients compared with controls, and the resting cardiac index was an independent predictor of the diffusing capacity.

The heart of the senior oarsman : an echocardiographic evaluation

We evaluated left ventricular mass and function in 15 oarsmen aged 78 (65-82) yr (median and range) and in 15 sedentary males aged 72 (65-81) yr by 2-D and M-mode echocardiography and cycle ergometry. The weekly time spent exercising among the oarsmen was 6 (2-18) h and two of the oarsmen were former national and international champions. The two groups of subjects had similar weight, height, and resting blood pressure. The oarsmen reached a maximal work rate of 142 (117-174) vs 113 (75-150) W for the sedentary group (P < 0.01). The internal diameters of the left ventricle were not significantly different, but the septum and posterior wall thicknesses were larger in the oarsmen (11 (8-20) vs 9 (7-11) mm, and 9 (8-13) vs 8 (7-19) mm, respectively, P < 0.023). Thus, the left ventricular mass index of the oarsmen was 19% larger (127 (101-284) vs 103 (74-134) g.m-2, P < 0.01). Also, the systolic function appeared to be superior in the oarsmen as the fractional shortening was 0.45 (0.28-0.55) vs 0.36 (0.18-0.49) in the controls (P < 0.05). In conclusion, we found that long-term rowing in the senior oarsman is associated with enlarged myocardial wall thickness, a normal systolic function, and a high work capacity.

Maximal inspiratory pressure following endurance training at altitude

Effects of endurance training on maximal inspiratory pressure and fatigue were evaluated after 5 weeks. Twelve male and 9 female untrained subjects were matched in the three groups for sex and maximal oxygen uptake (VO2 max). Training was performed at 70% VO2max; 45 min day-1; 5 days week-1 (n = 7); and at the same relative (n = 7) and absolute (n = 7) work loads in a pressure chamber corresponding to 2500 m (560 mmHg). Work load was increased every week to maintain the training heart rate. Maximal respiratory pressure was measured at the mouth before and 30, 60 and 120 s after maximal exercise. With no significant difference between the three groups of subjects, VO2max increased from 2.96 (1.98-4.47) (median and range for 21 subjects) to 3.33 (2.50-4.72) 1 min-1 (p < 0.001) and ventilation (VE max) from 109 (57-147) to 123 (73-148) 1 min-1 (p < 0.001), while maximal heart rate decreased from 193 (180-211) to 192 (169-207) beats min-1 (p < 0.01). Maximal inspiratory pressure (87 (56-115) mmHg), inspiratory muscle fatigue (18 (-2-43)%, p < 0.001), and arterial oxygen tension during exercise (12.4 (9.9-15.6)kPa) were similar before and after training. The results demonstrate that training at simulated altitude at 2500 m does not increase VE max or VO2 max above the increases obtained from training at sea level. Furthermore, VEmax and VO2 max increased approximately 13% despite unchanged maximal inspiratory pressure and inspiratory muscle fatigue.(ABSTRACT TRUNCATED AT 250 WORDS)

Correction: The Single-Breath Diffusing Capacity of CO and NO in Healthy Children of European Descent

[This corrects the article DOI: 10.1371/journal.pone.0113177.].