ECSS Paris 2023: OP-PN20
INTRODUCTION: Mild hypoxia, restricted activity, and disruption of individual routines may affect health and performance following short-haul air travel (SHAT)1. However, the extent to which SHAT affects physiological responses and performance indices of high-level football players remains unknown2. This study aimed to investigate the impact of two simulated SHAT of different duration (4-h and 2-h) on cortisol and immunoglobulin-A (sIgA) responses, external training load, and cognitive performance of high-level football players. METHODS: Nineteen high-level football players completed, in a randomized order, two SHAT, one week apart, each one lasting 4-h and 2-h, followed by a control condition (CON). Oxygen saturation (SpO2%) and heart rate (HR) were continuously recorded during CON and simulated flights. Salivary cortisol and sIgA, were measured and wearable GPS trackers and the Flanker test were used to evaluate physiological responses, training-related external load metrics, and cognitive performance (i.e., reaction time), respectively, one day before (D-1), the day of the flight (DF), one-day after the travel (D+1). RESULTS: A notable decline in SpO2% accompanied by a rise in HR was observed during SHAT in comparison to the CON (p<0.01). sIgA was decreased at D+1 compared to D-1 only following the 4-h flight (p<0.05). No significant differences were observed for cortisol among conditions (p>0.05). Total distance covered, very high-speed running distance, and number of accelerations were decreased at D+1 compared to CON after the 2-h SHAT (p<0.05). Similarly, high-speed running distance and number of decelerations were decreased at D-1 compared to CON after the 2-h SHAT (p<0.05). Reaction time was slower at D+1 compared to CON after the 4-h SHAT (p=0.04). CONCLUSION: This study showed impaired immunological responses and reaction time after the 4-h SHAT. However, the extent to which external load metrics are affected by SHAT warrants further investigation. 1. Fowler P, Duffield R, Vaile J. Effects of simulated domestic and international air travel on sleep, performance, and recovery for team sports. Scand J Med Sci Sports. 2015;25(3):441-451. 2. Fowler P, Duffield R, Waterson A, Vaile J. Effects of Regular Away Travel on Training Loads, Recovery, and Injury Rates in Professional Australian Soccer Players. International Journal of Sports Physiology and Performance. 2015;10(5):546-552.
Read CV Dimitris StergiopoulosECSS Paris 2023: OP-PN20
INTRODUCTION: Cerebral function is critically dependent upon the adequate and continuous delivery of oxygen to the brain through the active regulation of cerebral blood flow (CBF) (Powers et al., 1985). Hypoxia and exercise result in competing vasoactive stimuli, which in turn influences CBF, therefore the cerebrovascular response to exercise in hypoxia remains unclear (Nobrega et al., 2014). Moreover, males and females had similar CBF responses during incremental exercise in normoxia (Chamoun et al., 2023), but sex-specific differences in cerebrovascular regulation during exercise in hypoxia remain unknown. Aim: This study aimed to i) examine the impact of moderate hypobaric hypoxia on CBF during incremental cardiopulmonary cycle exercise test (CPET) to volitional exhaustion; ii) examine the effect of sex on cerebrovascular response during exercise in hypoxia and normoxia. METHODS: In a randomised cross over study, 24 healthy active participants (25±3 years, 12 males and 12 females) completed two separate incremental CPET in normoxia (FiO2=0.21) and moderate hypobaric hypoxia (FiO2=0.14). Middle cerebral artery mean blood velocity (MCAv-mean), an estimate for CBF, was measured continuously throughout exercise using Transcranial Doppler Ultrasound. Breath-by-breath metabolic data, heart rate, oxygen saturation, and blood pressure were measured continuously throughout exercise. Blood lactate (BLa) was measured at the end of each exercise stage. RESULTS: In comparison to normoxia, hypoxia induced significant increase in MCAv-mean, ventilation (VE), BLa with lower partial pressure of end-tidal carbon dioxide (PetCO2) during submaximal exercise (e.g. at the highest equivalent work rate of 140 watts, MCAv-mean: 68.3±13.5 vs. 59.8±14.6 cm/sec; VE: 69.4±9.8 vs. 59.0±11.8 L/min; BLa: 4.1±1.0 vs. 3.5±0.9 mmol/L; PetCO2: 35.0±3.5 vs. 39.6±5.3 mmHg, P < 0.01 for all). Females exhibited higher MCAv-mean and VE, and lower PetCO₂ than males during submaximal work rates (80-140 watts) in both normoxia and hypoxia. At 140 watts, MCAv-mean was higher in females than males in both normoxia (64.7±13.0 vs. 54.4±14.8 cm/sec) and hypoxia (69.7±13.2 vs. 60.17±12.6 cm/sec, P < 0.01). Hypoxia induced similar relative changes in MCAv-mean across sexes. CONCLUSION: In hypoxic condition, an increase in MCAv-mean during exercise acts as a compensatory mechanism to preserve cerebral oxygen delivery in response to reduced oxygen saturation levels. Females showed consistently higher CBF compared to males in both normoxia and hypoxia, but hypoxia affected MCAv-mean in both sexes similarly. These findings suggest intrinsic sex differences in cerebrovascular regulation during exercise, independent of oxygen availability. References: Powers et al. Journal of Cerebral Blood Flow & Metabolism 1985; 5(4), 600–608. Nobrega et al. Biomed Res Int. 2014; 2014:478965. Chamoun et al. J Appl Physiol. 2023; 1;134(6):1470-1480.
Read CV Azmy FaisalECSS Paris 2023: OP-PN20
INTRODUCTION: Approximately 81.6 million individuals reside permanently at altitudes above 2,500 meters, with many more intermittently exposed to high-altitude environments through travel, work, or recreation. Hypoxia, a reduction in available oxygen, can adversely affect human physiology and cognitive performance. While younger adults often exhibit resilience to moderate hypoxia[1], the extent to which middle-aged adults experience cognitive changes remains less established. Age-related declines in neurovascular coupling and cerebral autoregulation may increase susceptibility to hypoxia-induced impairments, underscoring the importance of focused research in middle-aged adults. METHODS: Sixteen healthy participants (aged 45–65 years) were recruited to investigate the impact of acute normobaric hypoxia on cognitive performance and cerebral oxygenation. Each participant attended four separate sessions in a hypoxia chamber, simulating altitudes of 0 m (normoxia, FiO2≈20.9%), 1,500 m (low altitude, FiO2≈17.3%), 3,000 m (moderate altitude, FiO2≈14.5%), and 4,500 m (high altitude, FiO2≈12%). At each session, participants completed a cognitive test battery comprising the Stroop test, N-back task, Corsi block-tapping test, and Operation Span Task. Cerebral oxygenation was assessed continuously using near-infrared spectroscopy, measuring tissue saturation index (TSI), total hemoglobin (tHb), deoxyhemoglobin (HHb), and oxyhemoglobin (O2Hb). Changes in these parameters (ΔTSI%, ΔtHb, ΔHHb, and ΔO2Hb) were determined by subtracting normoxic resting values from those obtained during each hypoxia level. Perceived exertion was evaluated after each cognitive task using the DP15 rating scale. RESULTS: Exposure to graded hypoxia significantly impaired cognitive performance in middle-aged adults, particularly at moderate to high altitudes (3,000–4,500 m). Compared with normoxia, participants exhibited slower reaction times and decreased accuracy on the Stroop test (p < 0.05), reduced accuracy on the N-back task (p < 0.05), as well as on the Corsi block-tapping test (p < 0.05). These deficits were more pronounced under high-altitude conditions (4,500 m). Correlation analyses indicated a strong positive relationship between reduced oxygen availability (SpO2) and heightened perceived exertion (p < 0.05), suggesting that lower oxygen levels may directly contribute to cognitive performance decrements. CONCLUSION: Acute normobaric hypoxia at simulated moderate to high altitudes significantly affects cognitive function in middle-aged adults, underlining a potential vulnerability in this demographic. These findings emphasize the importance of monitoring and mitigating hypoxia-related risks for individuals exposed to lower oxygen environments and warrant further research into interventions that could preserve cognitive performance at altitude.
Read CV Ayoub BoularesECSS Paris 2023: OP-PN20