Undiagnosed exercise-induced bronchoconstriction in ski-mountaineers

Because the practise conditions put the ski-mountaineering athletes potentially at risk for exercise-induced bronchoconstriction (EIB), this study was conducted to estimate the prevalence of EIB in this population. Thirty-one highly-trained ski-mountaineers with racing experience participating in the race were evaluated. EIB was determined after a European race at high altitude and frigid conditions. Pre-race investigations included pulmonary function measurements and a questionnaire enquiring about i) training habits, ii) respiratory history during training and/or competition. Pulmonary function was also tested after the race. None of the athletes reported a basal airway obstruction. Two groups were determined after post-race airway response: i) EIB (+) group exhibiting a fall in FEV (1) > or = 10 % (n = 15) and ii) EIB (-) without fall in FEV (1) or fall < 10 % (n = 16). Neither training habits nor baseline lung function were associated with the post-race airway response. Six of the 31 ski-mountaineers had a previous physician-made diagnosis of asthma and/or EIB, nevertheless 23 of our athletes complained about at least one characteristic symptom of asthma during practise. Four of our 15 EIB (+) had a previous physician-made diagnosis of asthma/EIB indicating that 73 % of EIB (+) athletes were undiagnosed for EIB. The proportion of allergic athletes was not significantly different between EIB (+) and EIB (-). This study showed that approximatively half of highly-trained ski-mountaineers with racing experience can develop EIB after a race and that 73 % of them are unaware of the problem.

Effect of acute hyperoxia during exercise on quadriceps electrical activity in active COPD patients

AIMS

This study investigated whether acute hyperoxia improves electrical muscle activity in active chronic obstructive pulmonary disease (COPD) patients with mild hypoxemia (rest PaO(2) = 9.1 +/- 0.4 kPa).

METHODS

Two identical incremental exercise tests were performed by nine patients while breathing either air or 30% oxygen. Pulmonary gas exchanges, venous concentrations of lactate and pyruvate, and the electromyographic signal of the quadriceps muscle (vastus lateralis and vastus medialis) were sampled each minute.

RESULTS

Peak working capacity increased significantly in hyperoxia (94.4 +/- 5.2W) compared with normoxia (85.4 +/- 5.8W, P < 0.01). During hyperoxic exercise and for a given work load, oxygen uptake was increased (P < 0.001) and ventilation decreased (P < 0.05). Lactate concentration was significantly decreased (P < 0.01) at isowork level and during recovery (respectively - 26% and at least - 15%). In the quadriceps muscle, M-wave amplitude (P < 0.05), root mean square (P < 0.01) and root mean square/oxygen uptake ratio (P < 0.001) were significantly increased during hyperoxic exercise compared with room air. Although median frequency values did not differ between conditions, the median frequency was significantly decreased for higher exercise intensity in hyperoxic condition. These modifications reflected better aerobic metabolism, later emergence of muscle fatigue, and greater muscle excitability and activation for the same level of exercise under hyperoxic condition.

CONCLUSION

These data suggest that the acute addition of oxygen in active COPD patients improves their muscle electrical activity during dynamic exercise. Hypoxemia-induced skeletal muscle dysfunction most probably acts through mechanisms based on oxygen availability.

[Confronting the statistics on intra-European migration: toward greater harmonization?]

"Each international migration stream can be enumerated twice: at the time of departure from the country of emigration and at the time of arrival in the country of immigration. In practice, errors in international migration statistics are a major obstacle to the accurate analysis of migration flows. In connection with the process of harmonization set in train by Eurostat several years ago, a method of correcting defective migration data is proposed here, which makes use of this double enumeration. The method is applied to available data in a preliminary analysis. The correction factors presented here through this mathematical approach should turn out to be useful in more than one respect: to illuminate substantial problems of incompatibility of migration data and to follow the progress of the harmonization of those data." (SUMMARY IN ENG)

[Migratory flows in the Mediterranean Basin]

Recent trends in international migration in the Mediterranean region are analyzed, with the focus on South-North migration to Europe. "This migration towards Western Europe has taken various forms, from labour force migration, in a first phase, to family reunification, and more recently, asylum requests and irregular immigration. These migratory flows must be understood within the context of a severe imbalance--demographic and economic--between the Southern and Northern banks of the Mediterranean. Europe and especially the European Union is directly confronted by this persistent migratory pressure coming from the other Mediterranean countries. Its future can only be conceived of through new and innovative forms of cooperation with its Mediterranean partners." (SUMMARY IN ENG)

Prediction of VO(2peak) in wheelchair-dependent athletes from the adapted Léger and Boucher test

PURPOSE

:The purpose of this study was to provide a predictive peak oxygen uptake ([V]O(2) peak) equation in wheelchair-dependent athletes using the Adapted Léger and Boucher test. SUBJECTS AND PROTOCOL: :Fifty-six wheelchair-dependent athletes, 47 males and nine females (30.3+/-4 years), underwent a clinical examination to assess their anthropometric characteristics: height, mass, body mass index (BMI), lean body mass, arm length, and muscular arm volume. They performed a deceleration field test to assess the subject-wheelchair resistance defined as a mechanical variable, and they then performed the Adapted Léger and Boucher test to assess physiological data at maximal exercise ([V]O(2) peak, heart rate max) concomitantly with biomechanical (number of pushes) and performance variables (maximal aerobic velocity Va(max) and maximal distance). The [V]O(2) peak was measured directly using a portable telemetric oxygen analyzer. Subjects were then randomly assigned to an experimental group (n=49) to determine the predictive equation, and a validation group (n=7) to check the external validity of the equation.

RESULTS

A stepwise multiple regression with [V]O(2) peak (l min(-1)) as the dependent variable led to the following equation: [V]O(2) peak=0.22 Va(max) - 0.63 log(age)+0.05 BMI 0.25 level+0.52, with r(2)=0.81 and SEE=0.01. Paraplegic subjects with high and low lesion level spinal injuries were attributed the coefficient of 1 and 0, respectively. The external validity of the equation was positive since the predicted [V]O(2) peak values did not significantly differ from directly measured [V]O(2) peak (P>0.05).

CONCLUSION

We concluded that [V]O(2) peak in wheelchair-dependent athletes was predictable using the equation of the present study and the described incremental test.

[Daltonism and the genetics of aging]

In order to test whether mutations giving rise to color vision deficiencies are more frequently inherited from older fathers, an exhaustive screening of births in the Namur region has allowed to isolate a sample of 225 descending sons of maternal grandfathers who were older than 45 years at their daughter's birth. The incidence of color vision defects was compared between this set of cases and three control groups totalling 959 boys from independent families. While these comparisons were not conclusive, we propose new hypotheses concerning the population dynamics of color vision deficiencies. Neomutations in X-linked pigment genes may be a marker of the overall genetic load borne by the X chromosome. Selection against such loaded X chromosomes may occur in the second generation, either in the course of embryogenesis, or during female gametogenesis. The future assessment of these novel hypotheses relies on the arbitration of molecular genetics.

Reproducibility of the Adapted Leger and Boucher Test for wheelchair-dependent athletes

STUDY DESIGN

This study analyzed the reproducibility of a field test. In a previous study, we showed that this test, the Adapted Leger and Boucher Test (ALBT), was progressive and maximal. The Leger and Boucher predictive equation for able-bodied subjects was not accurate for WD athletes, however, and a new predictive equation is needed.

OBJECTIVES

To determine the reproducibility of an adapted incremental field test for wheelchair-dependent (WD) athletes.

SETTING

France at Montpellier.

METHODS

The proposed protocol was conducted on a 400 m track. Eight male paraplegics (mean age: 30.8+/-5.1 years) performed the test three times in the same conditions, ie same time of day, same wheelchair, same material. Maximal heart rate (HRmax) and maximal speed (Smax) were measured.

RESULTS

We found no significant differences (P>0.05) between tests for either variable. The Bland and Altman graphic analyses showed a good reproducibility for both variables. Lastly, the reproducibility coefficients of HRmax and Smax were very low (2% and 1%, respectively).

CONCLUSION

The ALBT is reproducible concerning measurements of HRmax and Smax. A valid predictive equation of maximal oxygen uptake from the Smax is now needed for WD athletes during this field test.

Aerobic metabolism and cardioventilatory responses in paraplegic athletes during an incremental wheelchair exercise

The aims of the present study were: (1) to assess aerobic metabolism in paraplegic (P) athletes (spinal lesion level, T4-L3) by means of peak oxygen uptake (VO2peak) and ventilatory threshold (VT), and (2) to determine the nature of exercise limitation in these athletes by means of cardioventilatory responses at peak exercise. Eight P athletes underwent conventional spirographic measurements and then performed an incremental wheelchair exercise on an adapted treadmill. Ventilatory data were collected every minute using an automated metabolic system: ventilation (l x min[-1]), oxygen uptake (VO2, l x min[-1], ml x min[-1] x kg[-1]), carbon dioxide production (VCO2, ml x min[-1]), respiratory exchange ratio, breathing frequency and tidal volume. Heart rate (HR, beats x min[-1]) was collected with the aid of a standard electrocardiogram. VO2peak was determined using conventional criteria. VT was determined by the breakpoint in the VCO2 - VO2 relationship, and is expressed as the absolute VT (VO2, ml x min[-1] x kg[-1]) and relative VT (percentage of VO2peak). Spirometric values and cardioventilatory responses at rest and at peak exercise allowed the measurement of ventilatory reserve (VR), heart rate reserve (HRr), heart rate response (HRR), and O2 pulse (O2 P). Results showed a VO2peak value of 40.6 (2.5) ml x min(-1) x kg(-1), an absolute VT detected at 23.1 (1.5) ml x min(-1) x kg(-1) VO2 and a relative VT at 56.4 (2.2)% VO2peak. HRr [15.8 (3.2) beats min(-1)], HRR [48.6 (4.3) beat x l(-1)], and O2 P [0.23 (0.02) ml x kg(-1) x beat(-1)] were normal, whereas VR at peak exercise [42.7 (2.4)%] was increased. As wheelchair exercise excluded the use of an able-bodied (AB) control group, we compared our VO2peak and VT results with those for other P subjects and AB controls reported in the literature, and we compared our cardioventilatory responses with those for respiratory and cardiac patients. The low VO2peak values obtained compared with subject values obtained during an arm-crank exercise may be due to a reduced active muscle mass. Absolute VT was somewhat comparable to that of AB subjects, mainly due to the similar muscle mass involved in wheelchair and arm-crank exercise by P and AB subjects, respectively. The increased VR, as reported in patients with chronic heart failure, suggested that P athletes exhibited cardiac limitation at peak exercise, and this contributed to the lower VO2peak measured in these subjects.

Validation of an incremental field test for the direct assessment of peak oxygen uptake in wheelchair-dependent athletes

The aim of this study was to validate an incremental field test performed by wheelchair-dependent (WD) athletes. Nine male paraplegic subjects (mean age 28.9 +/- 4.2 years) performed an incremental field test (FT) and a comparable laboratory test (LT) with their own usual wheelchairs. Both tests started with an initial speed of 4 km.hr(-1) and increased by increments of 1 km.hr(-1) every minute until volitional exhaustion. The FT was an adapted Léger and Boucher test (ALBT) and was conducted on a 400 m tartan field marked-off every 50 m with pylons. Ventilatory data were collected every 15 s using a portable telemetric system (Cosmed K2, JFB International, Italy). The LT was performed on an adapted treadmill (Sopur, Germany) and ventilatory data were collected every minute using a breath-by-breath automated system (CPX, Medical Graphics, MN, USA). The LT and the FT were not significantly different for duration (8 min 50 +/- 1 min 24 vs 9 min 55 +/- 29 s), percentage of maximal heart rate (HR, 86.2 +/- 3.9 vs 89.7 +/- 5.3%), maximal minute ventilation (VE, 101.6 +/- 28.5 vs 96.8 +/- 28.2 1.min(-1)) and peak oxygen uptake (VO2 peak, 39.7 + 7.3 vs 36.1 + 5.8 ml.kg(-1).min(-1) assessed with the CPX and the K2, respectively. We concluded that the FT proposed in the present study is a valid test for direct VO2 peak assessment in wheelchair athletes using a portable VO2 telemetric system. Nonetheless, the Léger and Mercier model equation did not accurately predict VO2 max and further investigation is needed to determine a valid VO2 max prediction equation for these subjects during the FT.