Hypoxic Training Research Articles

Effects of 2 Different Protocols of Repeated-Sprint Training in Hypoxia in Elite Female Rugby Sevens Players During an Altitude Training Camp.

Repeated-sprint training in hypoxia (RSH) is an effective way of improving physical performance compared with similar training in normoxia. RSH efficiency relies on hypoxia severity, but also on the oxidative-glycolytic balance determined by both sprint duration and exercise-to-rest ratio. This study investigated the effect of 2 types of RSH sessions during a classic altitude camp in world-class female rugby sevens players. Sixteen players performed 5 RSH sessions on a cycle ergometer (simulated altitude: 3000m above sea level [asl]) during a 3-week natural altitude camp (1850m asl). Players were assigned to 2 different protocols with either a high (RSH1:3, sprint duration: 8-10s; exercise-to-rest ratios: 1:2-1:3; n = 7) or a low exercise-to-rest ratio (RSH1:5, sprint duration: 5-15s; exercise-to-rest ratios: 1:2-1:5; n = 9). Repeated-sprint performances (maximal and mean power outputs [PPOmax, and PPOmean]) were measured before and after the intervention, along with physiological responses. PPOmax (962 [100] to 1020 [143]W, P = .008, Cohen d = 0.47) and PPOmean (733 [71] to 773 [91]W, P = .008, d = 0.50) increased from before to after. A significant interaction effect (P = .048, d = 0.50) was observed for PPOmean, with a larger increase observed in RSH1:3 (P = .003). No interaction effects were observed (P > .05) for the other variables. A classic altitude camp with 5 RSH sessions superimposed on rugby-sevens-specific training led to an improved repeated-sprint performance, suggesting that RSH effects are not blunted by prolonged hypoxic exposure. Interestingly, using a higher exercise-to-rest ratio during RSH appears to be more effective than when applying a lower exercise-to-rest ratio.

The Anaerobic Speed Reserve Influences Speed And Power Improvements From Repeated-sprint Training In Hypoxia (RSH) In World-class Short-track Speed Skaters

The Anaerobic Speed Reserve Influences Speed And Power Improvements From Repeated-sprint Training In Hypoxia (RSH) In World-class Short-track Speed Skaters

Intermittent Hypoxic Exposure And Training Have Potential To Maintain Elevated Hemoglobin Mass After Hypoxic Camps

Intermittent Hypoxic Exposure And Training Have Potential To Maintain Elevated Hemoglobin Mass After Hypoxic Camps

Effect Of Short Period Hypoxic Training On Cardiopulmonary Responses And Metabolisms During Exercise In Hypoxia

Effect Of Short Period Hypoxic Training On Cardiopulmonary Responses And Metabolisms During Exercise In Hypoxia

SPRINT INTERVAL TRAINING IN HYPOXIA AND EXERCISE PERFORMANCE – A SHORT REVIEW

Hypoxia is often used during training to augment metabolic load and heighten physiological adaptations with the aim of exercise performance improvements. The recently established altitude training method »sprint interval training in hypoxia« (SIH) requires individuals to perform multiple 30 s Wingate sprints under hypoxia, interspersed with 3–5 min recovery periods. As the execution of repeated supramaximal efforts in hypoxia does not seem to be compromised, it was hypothesized that SIH might further augment exercise performance compared to sprint interval training in normoxia (SIT). To elucidate the usefulness of hypoxia during sprint interval training for exercise performance a systematic review of the available literature was conducted. The PubMed, SportDiscusTM, and Web of Science online databases were searched for original articles – published up to March 2023 – assessing changes in exercise performance following SIH and SIT. Six studies (randomized controlled trials (RCTs)) were identified, evaluating SIH interventions lasting 2–6 weeks. Currently, the available scientific literature does not suggest that SIH additively augments exercise performance in comparison to SIT. The potential changes in anaerobic thresholds after SIH, but not after SIT require further investigation to fully elucidate the subsequent effects on exercise performance. Nevertheless, there is evidence to support beneficial peripheral adaptations known to increase the oxidative and glycolytic capacity, especially in type II, fast-twitch fibers, following SIH, but not SIT. These local adaptations could potentially enable superior improvement in exercise performance after long enough SIH training protocols. Future RCTs on SIH and, particularly, on the performance-related underlying mechanisms seem warranted.

MOLECULAR AND CELLULAR MECHANISMS OF HYPOXIC RESPONSE

Hypoxia is a typical pathological process characterized by oxygen tissue deficiency with the pathological and protective-compensatory reactions. The article briefly outlines the issues of hypoxia study and interval hypoxic training in clinical and rehabilitation practice while treating various diseases and pathological processes. The authors consider types of physiological and pathological responses to hypoxia, key aspects in the pathogenesis of normo- and hypobaric hypoxia under normal and reduced atmospheric pressure, and stages of hypoxia development. Physiological and biochemical responses to interval hypoxic training are associated with oxidative stress, which develops as a result of an imbalance between the pro- and antioxidant systems, and excessive production of reactive oxygen species. Interval hypoxic training is aimed at adequate activation of defense systems with the formation of stable adaptation to damaging factors. The authors prove the key role of HIF-1α biological effects in the mechanisms of cellular and tissue adaptation to oxygen deficiency. The authors also analyze the role of adenosine and adenosine receptors in acute and chronic inflammatory diseases associated with tissue hypoxia.

Time Decay in the Performance Benefits From Repeated-Sprint Training in Hypoxia in World-Class Short-Track Speed Skaters.

In short-track speed skating, athletes need to possess specific physiological capabilities to perform explosive starts and to finish races with faster lap times than their opponents. Repeated-sprint training in hypoxia (RSH) can enhance repeated-sprint ability and high-intensity performance. This study aimed to evaluate the relationship between on- and off-ice performance indicators for training and testing purposes and how these are optimized with RSH in world-class short-track speed skaters including world and Olympic champions. RSH training was administered for 3 consecutive weeks, 3 times per week, at 3500m of simulated altitude. Testing sessions (on-ice: 3-lap, 27-lap; off-ice: cycling incremental test, 7-s and 30-s Wingate) were performed immediately before and 2 and 4weeks after RSH to determine the time course of decay. On-ice top speed showed a small and possibly beneficial change of ∼0.9% for the women and large and almost certain ∼0.7% improvement for the men 2weeks post-RSH. Cycling peak power showed a moderate and probable ∼5.4% improvement for the men 2weeks after RSH. These adaptations reverted to baseline 4weeks post-RSH. Wingate average power showed a small and possibly beneficial gain (∼3.4%) in performance 4weeks post-RSH. Although scientific controls could not be added due to the extremely high caliber of these athletes and low sample size of the national team, this study suggests that cycling RSH can be added immediately after on-ice training and can transfer into meaningful improvements on the ice in both male and female skaters.

Repeated-sprint training in hypoxia boosts up team-sport-specific repeated-sprint ability: 2-week vs 5-week training regimen.

To investigate (1) the boosting effects immediately and 4 weeks following 2-week, 6-session repeated-sprint training in hypoxia (RSH2-wk, n = 10) on the ability of team-sport players in performing repeated sprints (RSA) during a team-sport-specific intermittent exercise protocol (RSAIEP) by comparing with normoxic counterpart (CON2-wk, n = 12), and (2) the dose effects of the RSH by comparing the RSA alterations in RSH2-wk with those resulting from a 5-week, 15-session regimen (RSH5-wk, n = 10). Repeated-sprint training protocol consisted of 3 sets, 5 × 5-s all-out sprints on non-motorized treadmill interspersed with 25-s passive recovery under the hypoxia of 13.5% and normoxia, respectively. The within- (pre-, post-, 4-week post-intervention) and between- (RSH2-wk, RSH5-wk, CON2-wk) group differences in the performance of four sets of RSA tests held during the RSAIEP on the same treadmill were assessed. In comparison with pre-intervention, RSA variables, particularly the mean velocity, horizontal force, and power output during the RSAIEP enhanced significantly immediate post RSH in RSH2-wk (5.1-13.7%), while trivially in CON2-wk (2.1-6.2%). Nevertheless, the enhanced RSA in RSH2-wk diminished 4 weeks after the RSH (-3.17-0.37%). For the RSH5-wk, the enhancement of RSA immediately following the 5-week RSH (4.2-16.3%) did not differ from that of RSH2-wk, yet the enhanced RSA was well-maintained 4-week post-RSH (0.12-1.14%). Two-week and five-week RSH regimens could comparably boost up the effects of repeated-sprint training in normoxia, while dose effect detected on the RSA enhancement was minimal. Nevertheless, superior residual effects of the RSH on RSA appear to be associated with prolonged regimen.

Repeated-Sprint Training at 5000-m Simulated Altitude in Preparation for the World Rugby Women's Sevens Series: Too High?

The objective of this study is to investigate the effectiveness of novel repeated-sprint training in hypoxia (RSH) protocol, likely maximizing hypoxic stimulus (higher than commonly used) while preserving training quality (interset rest in normoxia). Twenty-three world-class female rugby sevens players performed four repeated-sprint training sessions (4 sets of 5 × 5-s cycle sprints-25-s intersprint recovery and 3-min interset rest) under normobaric hypoxia (RSH, exercise and interset rest at FiO 2 of 10.6% and 20.9%, respectively; n = 12) or normoxia (repeated-sprint training in normoxia; exercise and interset rest at FiO 2 of 20.9%; n = 11) during a 9-d training camp before international competition. Repeated-sprint ability (8 × 5-s treadmill sprints-25-s recovery), on-field aerobic capacity, and brachial endothelial function were assessed pre- and postintervention. Arterial oxygen saturation (pooled data: 87.0% ± 3.1% vs 96.7% ± 2.9%, P < 0.001) and peak and mean power outputs (sets 1 to 4 average decrease: -21.7% ± 7.2% vs -12.0% ± 3.8% and -24.9% ± 8.1% vs -14.9% ± 3.5%; both P < 0.001) were lower in RSH versus repeated-sprint training in normoxia. The cumulated repeated-sprint distance covered significantly increased from pre- to postintervention (+1.9% ± 3.0%, P = 0.019), irrespective of the condition ( P = 0.149). On-field aerobic capacity did not change (all P > 0.45). There was no significant interaction (all P > 0.240) or condition main effect (all P > 0.074) for any brachial artery endothelial function variable. Only peak diameter increased ( P = 0.026), whereas baseline and peak shear stress decreased ( P = 0.014 and 0.019, respectively), from pre- to postintervention. In world-class female rugby sevens players, only four additional repeated-sprint sessions before competition improve repeated-sprint ability and brachial endothelial function. However, adding severe hypoxic stress during sets of repeated sprints only did not provide supplementary benefits.

Development of some aerobic and anaerobic indicators in under-21 footballers using hypoxic training mask during the physical preparation period

This study aims to identify the effect of a training program using the hypoxic training mask on certain aerobic capacities (VMA, VO2max), on the effectiveness of the repetition rate (RSA), and on the explosive power of football players. The sample was deliberately selected and included 20 football players under the age of 21 from the Tiaret youth team, which plays in the second professional division. A total of 10 players were assigned to a control group and the other 10 players to an experimental group. The research used a series of physical tests that included VMA/VO2max intermittent yo-yo tests and RSA repetition rate efficiency tests, in addition to the explosive force tests using the MYOTEST device. The same training program was applied to the experimental and control groups, with the first one using the mask for 8 weeks. The study concluded that there are statistically significant differences in the pre- and post-measurement of the experimental and control groups in the measurement of aerobic and anaerobic capacities in favor of the experimental group, who wears the hypoxic mask. This underlines the importance of using modern technological means in the process of physical preparation and raising the level and efficiency of the players to reach the highest levels of achievement.

Research on Intermittent Hypoxia Training in Sports Based on Graph Neural Network

ABSTRACT To enhance the efficacy of intermittent hypoxia training in sports, this study presents an intelligent training model that utilizes a graph neural network. The model incorporates the particle filter method to establish a real-time processing system for physiological signals generated during intermittent hypoxia training, enabling frequency tracking and network sorting. Additionally, an ARMA model is utilized to facilitate real-time carrier frequency estimation and time-hopping detection of physiological signals. An enhanced frequency tracking method is proposed based on the Graph Neural Network (GNN) and ARMA model to improve the accuracy of frequency tracking while minimizing algorithm complexity. The experimental results indicate that the fusion of the GNN and the proposed intermittent hypoxia training model can effectively enhance the effects of intermittent hypoxia training in sports.

Intermittent hypoxic exposure and exercise training positively affect body composition and energy substrate utilization in high-fat diet-induced obese mice

Obesity is considered a major risk factor for increasing insulin resistance and inducing type 2 diabetes. Exercise is known to be the most effective treatment for improving obesity and insulin resistance through body fat loss. Furthermore, hypoxic exposure is known to increase carbohydrate oxidation and improve overall energy expenditure. Therefore, in this study, the effect of combined treatment of exercise and intermittent hypoxia on body composition and metabolic improvement was investigated after inducing obesity through a high-fat diet.The male 5-week-old ICR mice consumed high-fat diet for 7 weeks and were fed ad libitum. After 7 weeks, all groups were randomly divided into 4 groups: CN (sedentary; non-trained), HP (hypoxic exposure; non-trained), EX (trained), and HE (hypoxic exposure and trained). The HP and HE were only exposed hypoxia condition (12% oxygen concentration) for during light phase to coincide with the mouse inactive cycle. The EX and HE conducted treadmill training with 5 times a week for 4 weeks, and the exercise intensity was 70 % of VO2 max. After 4 weeks, the resting metabolic rate (RMR) was measured for all groups through respiratory gas. Then, all mice conducted dual energy X-ray absorptiometry to determine body composition.In body composition results, long-term exercise treatment showed a significantly decrease in fat mass and a significant increase in lean mass. In addition, in the HE, had significantly lower body fat mass and significantly higher lean mass than the EX. Furthermore, in the RMR results, it was investigated that overall energy expenditure increased through an increase in VO2 and VCO2 in the exercise group. However, in the HE, it was confirmed that carbohydrate oxidation at rest was significantly higher than that of the EX. In addition, it was confirmed that fasting blood glucose and HOMA-IR, an indicator of insulin resistance, were also significantly improved in the HE than in the EX.In summary, these results demonstrated that long-term exercise training decrease fat mass and increase in lean mass in high-fat diet-induced obese mice. In addition, it was confirmed that the HE, which intermittent hypoxic exposure combined treatment with exercise, significantly improved body composition compared to the EX, as well as improved carbohydrate oxidation at rest, fasting blood glucose, and HOMA-IR. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of Intermittent Hypoxia and Electrical Muscle Stimulation on Cognitive and Physiological Metrics.

This study describes the effects of interval hypoxic training and electrical muscle stimulation (EMS) technology on human productivity with the following metrics: biochemical indices, cognitive abilities, changes in oxygenated (HbO) and deoxygenated (Hb) hemoglobin concentrations over the prefrontal cortex, and functional connectivity via electroencephalography (EEG). All measurements according to the described technology were made before the start of training and one month later, right after it ended. The study involved middle-aged Indo-European men. Specifically, there were 14, 15, and 18 participants in the control, hypoxic, and EMS groups, respectively. EMS training improved reactions and nonverbal memory but decreased attention scores. Functional connectivity decreased in the EMS group while it increased in the hypoxic group. A result of the interval normobaric hypoxic training (IHT) was significantly improved contextual memory, with a p-value = 0.08. It was found that EMS training is more likely to cause stress on the body than positively affect cognitive functions. At the same time, interval hypoxic training can be considered a promising direction for increasing human productivity. The data obtained during the study can also help in the timely diagnosis of insufficient or overestimated indicators of biochemistry.

Efficacy of resistance training in hypoxia on muscle hypertrophy and strength development: a systematic review with meta-analysis

A systematic review and meta-analysis was conducted to determine the effects of resistance training under hypoxic conditions (RTH) on muscle hypertrophy and strength development. Searches of PubMed-Medline, Web of Science, Sport Discus and the Cochrane Library were conducted comparing the effect of RTH versus normoxia (RTN) on muscle hypertrophy (cross sectional area (CSA), lean mass and muscle thickness) and strength development [1-repetition maximum (1RM)]. An overall meta-analysis and subanalyses of training load (low, moderate or high), inter-set rest interval (short, moderate or long) and severity of hypoxia (moderate or high) were conducted to explore the effects on RTH outcomes. Seventeen studies met inclusion criteria. The overall analyses showed similar improvements in CSA (SMD [CIs] = 0.17 [− 0.07; 0.42]) and 1RM (SMD = 0.13 [0.0; 0.27]) between RTH and RTN. Subanalyses indicated a small effect on CSA for shorter inter-set rest intervals, moderate hypoxia and moderate loads favoring RTH. Moreover, a medium effect for longer inter-set rest intervals and a trivial to small effect for severe hypoxia and moderate loads favoring RTH was found on 1RM. Evidence suggests that RTH employed with moderate loads (60–80% 1RM) enhances both hypertrophy and strength. Hypertrophy appears to benefit from shorter (≤ 60 s) inter-set rest intervals during RTH while greater gains in strength are achieved with longer rest intervals (≥ 120 s). The use of moderate hypoxia (14.3–16% FiO2) seems to be somewhat beneficial to hypertrophy but not strength. Further research is required with greater standardization of protocols to draw stronger conclusions on the topic.

Long recovery induced by short exercise-to-rest ratio and effort duration determine the influence of hypoxia during repeated cycling sprints to exhaustion

Introduction&#x0D; Repeated sprints exercise (RSE) performed in hypoxia (RSH) induce greater performance improvement than in normoxia (Brocherie et al., 2017). It has been previously argued that RSH efficiency depend on the oxidative-glycolytic balance which is influenced by sprint duration and exercise-to-rest-ratio (E:R). Indeed, we recently showed that long sprint duration (e.g. 20 s vs 10 s or 5 s) blunts the additional impact of hypoxia on RSH with a constant large E:R of 1:22. However, E:R also influence acute response to RSH. Therefore, this study aims to compare acute responses during RSE to exhaustion with a short E:R (1:6) in normoxia (RSN) and hypoxia (FiO2 = 0.13) and the same sprint durations (5, 10 or 20 s) previously used.&#x0D; Methods&#x0D; On separate visits, 10 active participants completed in random order three RSH and three RSN sessions to exhaustion on a cycle-ergometer (Excalibur Sport, Lode) with three sprint durations and a constant short E:R of 1:6 (5:30; 10:60 and 20:120). Vastus lateralis muscle de-reoxygenation (Oxymon, Artinis Medical Systems) and power output were continuously recorded. Lower limb and breathing discomfort, blood lactate, and ratings of perceived exertion were evaluated immediately after exhaustion.&#x0D; Results&#x0D; Number of sprints and peak power output were higher while blood lactate was lower (all p &lt; 0.001) during 5:30 compared to 10:60 or 20:120. No condition or interaction effects were reported for blood lactate and exercise-related sensation. Blood lactate and muscle deoxyhemoglobin increase (p &lt; 0.001) and total hemoglobin decrease (p = 0.002) during sprint were more pronounced when sprint duration increased (no hypoxia effect).&#x0D; Discussion&#x0D; Similar deoxygenation changes during recovery were reported in hypoxia compared to normoxia suggesting that 1:6 ratio and the associated long recovery period seemed to allow myoglobin O2 store restauration, even with a FiO2 = 13%. Sprint effort should be interspersed by incomplete recovery making impossible the full O2 reloading myoglobin and PCr resynthesis. The increase in blood lactate and the concomitant decrease in muscle oxygenation during sprint with longer duration confirmed a switch in the oxidative-glycolytic balance for energy supply. Since short exercise-to-rest ratio blunt hypoxic effect during RSH due to too long recovery period, hypoxia did not participate to the switch from oxidative to glycolytic energy supply.&#x0D; Conclusion&#x0D; During RSE to exhaustion, a short exercise-to-rest ratio (i.e., 1:6) blunts the specific psychophysiological responses induced by hypoxia, probably due to too long of recovery period. Manipulating effort duration rather than hypoxic exposure is preferable to alter both anaerobic energy system solicitation and power produced during repeated cycling sprints to exhaustion using a short exercise-to-rest ratio.&#x0D; References&#x0D; Brocherie, F., Girard, O., Faiss, R., &amp; Millet, G. P. (2017). Effects of repeated-sprint training in hypoxia on sea-level performance: A meta-analysis. Sports Medicine, 47, 1651-1660. https://doi.org/10.1007/s40279-017-0685-3

Metabolic effects of non-drug therapy of post-Covid syndrome

The performed study is devoted to the analysis of the effect of mesodiencephalic (MDM) therapy and normobaric hypoxia on the carbohydrate and lipid metabolism in the complex rehabilitation of patients with post-COVID syndrome. It has been shown that the metabolic potential of MDM therapy is more pronounced than that of hypoxic training, and with the combined use of these factors, the therapeutic effect is significantly enhanced. This phenomenon is explained by the involvement of the body in the response reaction to the effects of various functional systems, while a supraaditive type of synergistic interaction of physical factors is noted. It is proved that one of the factors limiting therapeutic effect is the presence of metabolic syndrome in patients. The use of MDM therapy makes it possible to increase the sensitivity of the body to the action of insulin, while the regression of the insulin resistance index correlates with an improvement in well-being. At the same time, the formation of adaptive type reactions is recorded, which is confirmed by an increase in the activity of glucocorticoids. The combined use of physiofactors helps to reduce the manifestations of oxidative stress.

An Update to a Comprehensive Assessment of the Methods and Effectiveness of Resistance Training in Normobaric Hypoxia for the Development of Strength and Muscular Hypertrophy

Background. Training muscle capacities in hypoxic conditions increases some manifestations, such as hypertrophy and muscle strength, due to a change in the muscle phenotype as a result of the activation of hypoxia-inducible factors (HIF). Despite the proven benefits of resistance training in hypoxic conditions that allow conjecture regarding the effectiveness in facilitating muscular capacities in different populations, there is still controversy regarding the difference between resistance training in hypoxia and normoxia. The objective of this review was to compile the present evidence and update the methods and effectiveness of resistance training in simulated hypoxia for the development of strength and muscle hypertrophy. Methodology. A systematic search for an integrative review was carried out based on the preferred reporting guidelines for systematic reviews and meta-analysis (PRISMA) in 4 stages: identification, data selection, data collection and extraction, and quality evolution. Results. Four studies (92 participants) reported benefits in strength when training in hypoxia, three (101 participants) benefits in hypertrophy, and twelve (327 participants) benefits in strength and hypertrophy. Conclusion. Based on the findings of this systematic review, it is concluded that there are positive effects on muscle size and ability to generate force after a hypoxic training programme. However, some studies did not show a statistically greater benefit than for the normoxia groups, but several methodologies have been identified that promote the benefits of hypoxia.

Effect of Exercise on Arterial Stiffness in Healthy Young, Middle-Aged and Older Women: A Systematic Review.

Arterial stiffness, an age-dependent phenomenon, is improved with exercise, which in turn may prevent cardiovascular diseases in women. However, there is a lack of consolidated information on the impact of exercise on arterial stiffness among healthy women. The aim of this review was to (i) analyse the effect of exercise on arterial stiffness in healthy young, middle-aged, and older women, and (ii) recommend types, intensity, and frequency for each age group. Database searches on PubMed, ScienceDirect, Web of Science, and Scopus were conducted using PRISMA guidelines until September 2022. The keywords were: exercise, women/female, and arterial stiffness. The inclusion criteria were: healthy women, supervised exercise, and arterial stiffness measures. Study quality and bias were assessed using the PEDro scale. Fifty-one papers were classified into young (n = 15), middle-aged (n = 14), and older (n = 22) women. Improvements in arterial stiffness were observed among: young women (Pulse Wave Velocity, PWV: 4.9-6.6 m/s), following an 8-week high-intensity aerobic (3 days/week) or hypoxic high-intensity interval training; middle-aged women (PWV: 5.1-7.9 m/s), aerobic exercise with moderate intensity or stretching exercise at "moderate to heavy" (Borg Scale), 20-30 s per site, 10 s of rest interval for 30 min; and for older women (PWV: 7.9-15.6 m/s), resistance training at light intensity, aerobic exercise at any intensity, or a combination of the two exercises. This review shows that arterial stiffness increases with age in healthy women and has an inverse relationship with exercise intensity. Therefore, when prescribing exercise to improve arterial stiffness, age and arterial stiffness measures should be accounted for.

Intermittent hypoxia in sport nutrition, performance, health status and body composition.

Intermittent hypoxia refers to the discontinuous use of low oxygen levels in normobaric environment. These conditions can be reproduced in hypoxic tents or chambers while the individual is training in different physical activity protocols. Intermittent hypoxia can affect several body systems, impacting nutrition, physical performance, health status and body composition. Therefore, it is necessary to assess protocols, regarding time and frequency of exposure, passive exposure or training in hypoxia, and the simulated altitude. At the molecular level, the hypoxia-inducible factor-1α is the primary factor mediating induction of target genes, including vascular endothelial growth factor and erythropoietin. The goal of these molecular changes is to preserve oxygen supply for cardiac and neuronal function. In addition, hypoxia produces a sympathetic adrenal activation that can increase the resting metabolic rate. Altogether, these changes are instrumental in protocols designed to improve physical performance as well as functional parameters for certain pathological disorders. In addition, nutrition must adapt to the increased energy expenditure. In this last context, performing physical activity in intermittent hypoxia improves insulin sensitivity by increasing the presence of the glucose transporter GLUT-4 in muscle membranes. These changes could also be relevant for obesity and type 2 diabetes treatment. Also, the anorectic effect of intermittent hypoxia modulates serotonin and circulating leptin levels, which may contribute to regulate food intake and favor body weight adaptation for optimal sport performance and health. All these actions suggest that intermittent hypoxia can be a very effective tool in sports training as well as in certain clinical protocols.

Differential regulation of key metabolic markers in immune cell subsets of multiple sclerosis patients after hypoxic and normoxic training

Differential regulation of key metabolic markers in immune cell subsets of multiple sclerosis patients after hypoxic and normoxic training