ECSS Paris 2023: OP-PN16
INTRODUCTION: An increasing number of individuals reach HA for sports, leisure and work. HA hypoxia induces adaptive responses in unacclimatized lowlanders, including pulmonary vasoconstriction. The increase in pulmonary artery pressure and endothelial permeability during HA exposure may lead to lung extravascular fluid accumulation (interstitial edema, IE), affecting lung mechanics, mainly impairing the elastic properties of the respiratory system. Similarly, intense physical exercise (E) may lead to the development of IE. However, the effects of HA and E on pulmonary resistance (R) and reactance (X) have been poorly investigated. We aimed to study the impact of HA and E on lung mechanics in healthy men. METHODS: Lung mechanics of 36 soldiers of the Italian Alpine Corps (age: 34 ± 9 yr; height: 179 ± 7 cm; weight: 77 ± 8 kg) were assessed by respiratory oscillometry during quiet breathing, at rest and after an intense, standardized E. R and X were measured at 5, 11 and 19 Hz using the Resmon pro full device (RESTECH, Italy) at sea level (SL), and at 3375 m (Torino Hut, Mont Blanc). HA assessments were performed as follows: Day 1, 1-h post-arrival by cable car and after E; Day 2 at rest in the morning and after E; Day 3 at rest in the morning. At the same time, acute mountain sickness (AMS) symptoms were evaluated with the Lake Louise score (LLS). Post hoc comparisons with Bonferroni correction were performed following significant results (p < 0.05) from Friedman tests. Subjects were stratified into 3 groups: A (young officers), B (special forces operators) and C (military alpine guides). Between-group differences were explored using Kruskal Wallis test. RESULTS: R5, R11, R19 significantly decreased from SL to HA (i.e R5: 2.66 ± 0.84 vs. 2.28 ± 0.91 cmH2O/(s/L), p < .001; other values not shown). X5 and X11 significantly changed from SL to HA on Day 1 (-0.796 ± 0.236 vs. -1.006 ± 0.417, p < .001; 0.028 ± 0.318 vs. -0.127 ± 0.345 cmH2O/(s/L), p < .001), Day 2 (-1.001 ± 0.532, p = 0.019; -0.132 ± 0.345 cmH2O/(s/L), p < .001) and Day 3 (-0.985 ± 0.424, p = 0.002; -0.172 ± 0.503 cmH2O/(s/L), p < 0.001). Spearman correlations revealed a moderate but significant relationship between X5 on Day 1 and LLS on Day 2 (ρ = -0.334, p = 0.046). E induced variations in X5 were more pronounced at HA even if not significant (SL: 0.006 ± 0.192, Day 1: -0.020 ± 0.289, Day 2: -0.044 ± 0.306 cmH2O/(s/L); p > 0.05). ΔX5 between pre- and post-E revealed significant differences between groups B and C on Day 1 (-0.122 ± 0.149 vs. 0.131 ± 0.265 cmH2O/(s/L); p = 0.016). CONCLUSION: As expected, R decreased at HA due to reduced air density. HA and E lead to acute changes in lung mechanics, with primarily HA increasing respiratory system stiffness, probably due to lung IE development. To note that X5 changes preceded the development of AMS. Military alpine guides showed a more favourable E response at HA, suggesting better lung compliance, likely due to physiological adaptations acquired from prior HA exposure.
Read CV Guia TagliapietraECSS Paris 2023: OP-PN16
INTRODUCTION: Participation in mountain ultramarathons (MUM) has increased rapidly in recent years. One of the most extreme MUM, the Tor des Géants, is characterized by 330 km with a cumulative elevation gain of +24,000m and altitude ranging between 322 and 3,300 m. While it is known that such MUMs alter pulmonary volume and ventilatory flow, there is a paucity of data comprehensively assessing their effects on lung diffusing capacity (DL), and its kinetics during the race. Therefore, the aim of this study was to investigate changes in DL during and after a MUM. METHODS: A total of 53 volunteers participated in the study, but only 25 completed the race (i.e., 47% dropouts, in line with the overall rate). Participants underwent lung diffusing capacity before (pre-), after 148.7 km (mid-), and immediately (< 1-h) after (post-) the race. Pulmonary function was evaluated at pre- and post-. DL was assessed using the single-breath method with carbon monoxide (DLCO) and nitric oxide (DLNO), while pulmonary function was evaluated through the maximal flow-volume curve (HypAir, MGC Diagnostics, Saint Paul, MN), following standardized procedures. DLCO values were corrected for hemoglobin concentration (Hb201+, Hemocue, Ängelholm, Sweden). RESULTS: Forced vital capacity (-5.9%), forced expiratory volume in the first second (-5.7%), and peak expiratory flow (-7.1%) were significantly lower at post- compared to pre-. From pre- to mid-, alveolar volume (-6.8%, 7.6 ± 1.4 vs. 7.0 ± 1.2 L, p < 0.001), DLCO (-13.3%, 35.9 ± 6.1 vs. 33.4 ± 6.1 mL·min⁻¹·mmHg⁻¹, p = 0.008), DLNO (-11.4%, 175 ± 31 vs. 156 ± 39 mL·min⁻¹·mmHg⁻¹, p = 0.001), and membrane diffusing capacity for carbon monoxide (DmCO) (-11.5%, 152 ± 27 vs. 140 ± 27 mL·min⁻¹·mmHg⁻¹, p < 0.001) decreased, but they were not further impaired during the second part (mid- to post-) of the race. KCO and KNO (i.e., DLCO and DLNO expressed as the rate of gas transfer per unit of alveolar volume, respectively), were not modified from pre- to mid- (KCO: 4.79 ± 0.46 vs 4.76 ± 0.56 mL·min⁻¹·mmHg⁻¹·L⁻¹, NS ; KNO: 23.5 ± 2.4 vs. 23.01 ± 2.13 mL·min⁻¹·mmHg⁻¹·L⁻¹, NS) but were lower at post- (KCO: 4.58 ± 0.57 mL·min⁻¹·mmHg⁻¹·L⁻¹, p = 0.018; KNO: 22.03 ± 2.45 mL·min⁻¹·mmHg⁻¹·L⁻¹, p < 0.001). The volume of lung capillaries exposed to alveolar air decreased from pre- to mid-race (96 ± 19 vs. 87 ± 17 mL, p = 0.002) and further declined at post- (82 ± 17 mL, p = 0.007). However, the DLNO/DLCO ratio remained constant across all time points. CONCLUSION: DL alterations were driven by reduced alveolar volume during the first half of the race, while a decrease in lung capillary volume exposed to alveolar air likely contributed to further changes in the second half. The decline in DmCO, with a stable DLNO/DLCO ratio, suggests impaired membrane permeability. In conclusion, mountain ultramarathons result in a precociously observed substantial decline in lung diffusing capacity, with further pulmonary alterations occurring later during the race.
Read CV Antoine RaberinECSS Paris 2023: OP-PN16
INTRODUCTION: It has been shown that individuals with a breathing reserve (BR) less than 20% had a higher maximal oxygen uptake (VO2max) than those with a BR greater than 20% (1,2). Regrettably, the maximum voluntary ventilation (MVV) used to calculate BR was estimated from force expiratory volume in 1s (FEV1), even though recent studies have demonstrated that there is a significant difference between measured and estimated MVV (3). Therefore, the purpose is to assess differences in BR, with directly measured MVV, across a wide range of training statuses. METHODS: We examined 198 males (41±10yrs, 74.0±8.1kg, 175.2±6.5cm, 18.5±6.8%fat) and 60 females (37±14yrs, 59.1±8.4kg, 164.7±6.1cm, 25.7±8.6%fat) who performed a baseline MVV and a ramp incremental exercise test (consisting of a 3-min warm-up at 4-6 km/h followed by an incremental phase starting at 4-8 km/h, with speed increasing by 1 km/h per minute) to assess maximal ventilation (VEmax) and VO2max. BR was calculated by the following equation: BR=(1–VEmax/MVV)x100. Participants were classified based on BR depletion (yes/no) and categorized into low, medium, or high training levels according to VO2max tertiles. RESULTS: A main effect of training status on BR was found (F(2,249)=7.43; p<0.001; η2p=0.056). Pairwise comparisons showed higher BR in low (males: 24.59±17.09%; females: 21.36±13.93%) than in medium (males: 16.73±10.5%; females: 17.02±13.52%; p=0.022; d=0.53) or high training status (males: 14.56±12.93%; females: 12.09±10.65%; p<0.001; d=0.82). Moreover, females exhibited a lower BR than males (F(1,249)=5.39; p=0.021; η2p=0.021; d=0.46). The number of individuals who depleted the BR did not differ between the different training statuses in either males (χ2(2)=5.37; p=0.068) or females (χ2(2)=0.46; p=0.794). CONCLUSION: Lower BR was only observed in individuals with high or medium training status compared to those with low training status, and the number of individuals who depleted BR was not different between training statuses. These results allow us to better understand that reaching maximum possible ventilation during exercise (i.e., depleting the BR) is not a cause for ceasing exercise more prevalent in individuals with high training status, indicating that performance limitation by the respiratory system due to BR depletion is not more likely in individuals with the highest training status. REFERENCES 1.Rasch-Halvorsen Ø, et al.2019.DOI:10.1186/s12890-018-0762-x 2.McNeill J, et al.2022.DOI:10.1183/13993003.01821-2021 3.Otto-Yáñez M, et al.2020.DOI.10.3389/fphys.2020.00537
Read CV Blanca Rodríguez RedondoECSS Paris 2023: OP-PN16