Intermittent Hypoxic Training Research Articles

Intermittent Hypoxic Training Increases and Prolongs Exercise Benefits in Adult Untrained Women.

Alba Camacho-Cardenosa, Marta Camacho-Cardenosa, Johannes Burtscher, Pedro R. Olivares, Guillermo Olcina, and Javier Brazo-Sayavera. Intermittent hypoxic training increases and prolongs exercise benefits in adult untrained women. High Alt Med Biol. 00:00-00, 2024. Background: Exercising in hypoxia may confer multiple health benefits, but the evidence for specific benefits is scarce. Methods: We investigated effects of intermittent hypoxic training (IHT) on the quality of life and functional fitness of healthy adult women, in a double-blind, randomized, placebo-controlled study. Subjects performed 36 sessions of IHT (experimental group, n = 41; fraction of inspired oxygen [FIO2]: 0.17) or the same training in normoxia (control group, n = 41; FIO2: 0.21). Health-related quality of life, fitness tests, and hemoglobin levels were assessed before (T1), directly after (T2), and 4 weeks after (T3) cessation. Results: At T2, upper body strength (+14.96%), lower body strength (+26.20%), and agility (-4.94%) increased significantly in the experimental group compared to baseline but not in controls.The experimental group improved lower body strength more (by 9.85%) than controls at T2 and performed significantly better in walking (by 2.92%) and upper body strength testing (by 16.03%), and agility (by 4.54%) at T3. Perceived general health and vitality was significantly greater in the experimental group at T2 and T3 compared with T1. None of these improvements were observed in the control group. Conclusions: IHT is a promising strategy to induce long-lasting fitness benefits in healthy adult women.

The Impact of Normobaric Hypoxia and Intermittent Hypoxic Training on Cardiac Biomarkers in Endurance Athletes: A Pilot Study.

This study explores the effects of normobaric hypoxia and intermittent hypoxic training (IHT) on the physiological condition of the cardiac muscle in swimmers. Hypoxia has been reported to elicit both beneficial and adverse changes in the cardiovascular system, but its impact on the myocardium during acute exercise and altitude/hypoxic training remains less understood. We aimed to determine how a single bout of intense interval exercise and a four-week period of high-intensity endurance training under normobaric hypoxia affect cardiac marker activity in swimmers. Sixteen young male swimmers were divided into two groups: one undergoing training in hypoxia and the other in normoxia. Cardiac markers, including troponin I and T (cTnI and cTnT), heart-type fatty acid-binding protein (H-FABP), creatine kinase-MB isoenzyme (CK-MB), and myoglobin (Mb), were analyzed to assess the myocardium's response. We found no significant differences in the physiological response of the cardiac muscle to intense physical exertion between hypoxia and normoxia. Four weeks of IHT did not alter the resting levels of cTnT, cTnI, and H-FABP, but it resulted in a noteworthy decrease in the resting concentration of CK-MB, suggesting enhanced cardiac muscle adaptation to exercise. In contrast, a reduction in resting Mb levels was observed in the control group training in normoxia. These findings suggest that IHT at moderate altitudes does not adversely affect cardiac muscle condition and may support cardiac muscle adaptation, affirming the safety and efficacy of IHT as a training method for athletes.

The Effects of Intermittent Hypoxic Training on Anaerobic Performance in Young Men

This study aimed to comprehensively evaluate the effects of intermittent hypoxic training (IHT) on anaerobic performance in young, untrained men. Young men (n = 48) were randomly divided into two training groups and a control group. The training groups performed the same submaximal interval training (three times a week for 4 weeks) in normoxia (200 m asl) or in hypoxia (IHT) (FIO2 = 14.4%). The workloads for the interval training corresponded to the intensity of the ventilatory thresholds determined in a graded test. Participants performed a supramaximal all-out sprint test in normoxia twice: before and after the training. Significant improvement in both absolute peak power (p < 0.001; ES = 0.34) and relative peak power (p < 0.001; ES = 0.54) was noted after IHT. Similar changes were not observed either after training in normoxia (p = 0.14 and p = 0.26, for absolute and relative peak power, respectively) or in the control group (p = 0.34 and p = 0.51, for absolute and relative peak power, respectively). Compared to baseline, there were no significant changes in the absolute and relative mean power of either group after training. Intermittent hypoxic training in young, untrained men can be effective in improving their peak power, but does not significantly affect their mean power.

The Impact of Intermittent Hypoxic Training on Aerobic Capacity and Biometric-Structural Indicators among Obese Women-A Pilot Study.

Obesity, a common lifestyle-related condition, is correlated with factors like inadequate physical activity. Its connection to diverse health issues presents a significant challenge to healthcare. This pilot study investigated the effects of hypoxic training on aerobic capacity and biometric-structural indicators in obese women. The secondary objective was to determine the feasibility, effectiveness, and safety of the planned research procedures and their potential for larger-scale implementation. Forty-one non-trained women with first-degree obesity were randomly assigned to even normobaric hypoxic training (H + E), normoxic training (E), passive exposure to hypoxia (H), and a control group (C). Training sessions were conducted three times a week for four weeks (12 training sessions). Body composition parameters were assessed, metabolic thresholds were determined, and maximal oxygen consumption (VO2max) was measured before and after interventions. The results demonstrated that training in hypoxic conditions significantly affected somatic parameters, with the H + E group achieving the best outcomes in terms of weight reduction and improvements in body composition indicators (p < 0.001). Normoxic training also induced a positive impact on body weight and body composition, although the results were less significant compared to the H + E group (p < 0.001). Additionally, training in hypoxic conditions significantly improved the aerobic capacity among the participants (p < 0.001). The H + E group achieved the best results in enhancing respiratory endurance and oxygen consumption (p < 0.001). The results of this pilot study suggest, that hypoxic training can be effective for weight reduction and improving the aerobic capacity in obese women. Despite study limitations, these findings indicate that hypoxic training could be an innovative approach to address obesity and related conditions. Caution is advised in interpreting the results, considering both the strengths and limitations of the pilot study. Before proceeding to a larger-scale study, the main study should be expanded, including aspects such as dietary control, monitoring physical activity, and biochemical blood analysis.

Helpful to Live Healthier? Intermittent Hypoxic/Ischemic Training Benefits Vascular Homeostasis and Lipid Metabolism with Activating SIRT1 Pathways in Overweight/Obese Individuals

Introduction: The present study aimed to investigate whether and how normobaric intermittent hypoxic training (IHT) or remote ischemic preconditioning (RIPC) plus normoxic training (RNT) has a synergistic protective effect on lipid metabolism and vascular function compared with normoxic training (NT) in overweight or obese adults. Methods: A total of 37 overweight or obese adults (36.03 ± 10.48 years) were randomly assigned to 3 groups: NT group (exercise intervention in normoxia), IHT group (exercise intervention in normobaric hypoxic chamber), and RNT group (exercise intervention in normoxia + RIPC twice daily). All participants carried out the same 1-h exercise intervention for a total of 4 weeks, 5 days per week. Physical fitness parameters were evaluated at pre- and postexercise intervention. Results: After training, all three groups had a significantly decreased body mass index (p < 0.05). The IHT group had reduced body fat percentage, visceral fat mass (p < 0.05), blood pressure (p < 0.01), left ankle-brachial index (ABI), maximal heart rate (HRmax) (p < 0.05), expression of peroxisome proliferator-activated receptor-γ (PPARγ) (p < 0.01) and increased expression of SIRT1 (p < 0.05), VEGF (p < 0.01). The RNT group had lowered waist-to-hip ratio, visceral fat mass, blood pressure (p < 0.05), and HRmax (p < 0.01). Conclusion: IHT could effectively reduce visceral fat mass and improve vascular elasticity in overweight or obese individuals than pure NT with the activation of SIRT1-related pathways. And RNT also produced similar benefits on body composition and vascular function, which were weaker than those of IHT but stronger than NT. Given the convenience and economy of RNT, both intermittent hypoxic and ischemic training have the potential to be successful health promotion strategies for the overweight/obese population.

Effects of various living-low and training-high modes with distinct training prescriptions on sea-level performance: A network meta-analysis.

This study aimed to separately compare and rank the effect of various living-low and training-high (LLTH) modes on aerobic and anaerobic performances in athletes, focusing on training intensity, modality, and volume, through network meta-analysis. We systematically searched PubMed, Web of Science, Embase, EBSCO, and Cochrane from their inception date to June 30, 2023. Based on the hypoxic training modality and the intensity and duration of work intervals, LLTH was divided into intermittent hypoxic exposure, continuous hypoxic training, repeated sprint training in hypoxia (RSH; work interval: 5-10 s and rest interval: approximately 30 s), interval sprint training in hypoxia (ISH; work interval: 15-30 s), short-duration high-intensity interval training (s-IHT; short work interval: 1-2 min), long-duration high-intensity interval training (l-IHT; long work interval: > 5 min), and continuous and interval training under hypoxia. A meta-analysis was conducted to determine the standardized mean differences (SMDs) among the effects of various hypoxic interventions on aerobic and anaerobic performances. From 2,072 originally identified titles, 56 studies were included in the analysis. The pooled data from 53 studies showed that only l-IHT (SMDs: 0.78 [95% credible interval; CrI, 0.52-1.05]) and RSH (SMDs: 0.30 [95% CrI, 0.10-0.50]) compared with normoxic training effectively improved athletes' aerobic performance. Furthermore, the pooled data from 29 studies revealed that active intermittent hypoxic training compared with normoxic training can effectively improve anaerobic performance, with SMDs ranging from 0.97 (95% CrI, 0.12-1.81) for l-IHT to 0.32 (95% CrI, 0.05-0.59) for RSH. When adopting a program for LLTH, sufficient duration and work intensity intervals are key to achieving optimal improvements in athletes' overall performance, regardless of the potential improvement in aerobic or anaerobic performance. Nevertheless, it is essential to acknowledge that this study incorporated merely one study on the improvement of anaerobic performance by l-IHT, undermining the credibility of the results. Accordingly, more related studies are needed in the future to provide evidence-based support. It seems difficult to achieve beneficial adaptive changes in performance with intermittent passive hypoxic exposure and continuous low-intensity hypoxic training.

RESPOSTAS FISIOLÓGICAS AGUDAS À “HIPÓXIA INTERMITENTE DE RECUPERAÇÃO” NO HIIT

ABSTRACT Introduction: Traditional intermittent hypoxia training improves sport performance after short periods of exposure, but acute exposure to intermittent hypoxia leads to decreased training intensity and technical quality. The solution to overcome these negative effects may be to perform efforts in normoxia and the intervals between efforts in hypoxia, maintaining the quality of training and the benefits of hypoxia. Objective: This study aimed to evaluate the acute physiological responses to hypoxia exposure during recovery between high intensity efforts. Materials and methods: Randomized, one-blind, placebo-controlled study. Sixteen men performed a graded exercise test to determine their maximal intensity and two sessions of high-intensity interval training. The training intervals could be in hypoxia (HRT), FIO2: 0.136 or normoxia (NRT), FIO2: 0.209. During the two-minute interval between the ten one-minute efforts, peripheral oxygen saturation (SpO2), heart rate (HR), blood lactate ([La]), blood glucose ([Glu]) were constantly measured. Results: There were differences in HR (TRN = 120 ± 14 bpm; TRH = 129 ± 13 bpm, p &lt; 0.01) and SpO2 (TRN = 96.9 ± 1.0%; TRH = 86.2 ± 3.5%, p &lt; 0.01). No differences in [La] and [Glu] TRN (4.4 ± 1.7 mmol.l-1; 3.9 ± 0.5 mmol.l-1) and TRH (5.2 ± 2.0 mmol.l-1; 4.0 ± 0.8 mmol.l-1, p = 0.17). Conclusion: The possibility of including hypoxia only in the recovery intervals as an additional stimulus to the training, without decreasing the quality of the training, was evidenced. Level of Evidence II; Randomized Clinical Trial of Minor Quality.

Experimental study of the pattern of genes activated by multi-day intermittent hypoxia in the rat pancreas

Intermittent hypoxia affects a variety of pathological conditions in the body and is used in medicine to reproduce the sanogenic therapeutic effect. Intermittent hypoxia is used for clinical indications to improve lung function; increase the body’s adaptive capacity; in obstructive sleep apnoea syndrome; in anaemia, diabetes mellitus. In cancer radiotherapy, intermittent hypoxic training helps to increase the sensitivity of the tumour to treatment. Intermittent hypoxia is useful in rehabilitation medicine to improve the physical recovery of patients after surgery or injury to improve the body’s functional capabilities. However, to date, the activity of regulatory genes, that activate the molecular mechanisms of the above-mentioned sanogenic effects of intermittent hypoxia has not been sufficiently studied. The aim of the study: to determine the expression of hypoxia-related genes in pancreas of Wistar rats under intermittent hypoxia. Materials and methods. The CFX-96 Touch™ real-time reverse transcription polymerase chain reaction (PCR) (Bio-Rad, USA) and the RT2 Profiler™ PCR Array Rat Hypoxia Signalling Pathway kit (QIAGEN, Germany) were used to analyse gene expression in experimental animals, where 84 genes involved in the hypoxia signalling pathway identified in the pancreas were studied. Results. According to the results of PCR analysis of pancreatic samples from intact animals and animals exposed to hypoxic training, the activity of the gene panel can be distributed as follows: genes with high expression compared to the intact group of animals, genes with low expression compared to the intact group of animals and genes in which no significant changes were detected in the samples compared to the intact group of animals. We have found, that the genes Cops5, F10, Jmjd6, Lgals3, Rbpjl, Vegfa have high expression activity compared to the intact group of animals. Conclusions. The increase in the expression of Cops5 by 10.29 times, Lgals3 by 2.94 times and Rbpjl by 5.73 times as a result of intermittent hypoxia can be regarded as an activating factor for the increase in the proliferation of endocrine and exocrine pancreatic cells and the growth of their antiapoptotic potential. The 3.20-fold increase in Jmjd6 gene expression under intermittent hypoxia can be interpreted as a regulatory effect through protein dehydroxylation and promotion of antiapoptotic protein activity in endocrine and exocrine pancreatic cells. The 5.99-fold increased level of Vegfa expression may promote angiogenesis in the pancreas under intermittent hypoxia.

Enhancing HIF-1α–P2X2 signaling in dorsal raphe serotonergic neurons promotes psychological resilience

Major depressive disorder (MDD) is a devastating condition. Although progress has been made in the past seven decades, patients with MDD continue to receive an inadequate treatment, primarily due to the late onset of first-line antidepressant drugs and to their acute withdrawal symptoms. Resilience is the ability to rebound from adversity in a healthy manner and many people have psychological resilience. Revealing the mechanisms and identifying methods promoting resilience will hopefully lead to more effective prevention strategies and treatments for depression. In this study, we found that intermittent hypobaric hypoxia training (IHHT), a method for training pilots and mountaineers, enhanced psychological resilience in adult mice. IHHT produced a sustained antidepressant-like effect in mouse models of depression by inducing long-term (up to 3 months after this treatment) overexpression of hypoxia-inducible factor (HIF)-1α in the dorsal raphe nucleus (DRN) of adult mice. Moreover, DRN-infusion of cobalt chloride, which mimics hypoxia increasing HIF-1α expression, triggered a rapid and long-lasting antidepressant-like effect. Down-regulation of HIF-1α in the DRN serotonergic (DRN5−HT) neurons attenuated the effects of IHHT. HIF-1α translationally regulated the expression of P2X2, and conditionally knocking out P2rx2 (encodes P2X2 receptors) in DRN5−HT neurons, in turn, attenuated the sustained antidepressant-like effect of IHHT, but not its acute effect. In line with these results, a single sub-anesthetic dose of ketamine enhanced HIF-1α–P2X2 signaling, which is essential for its rapid and long-lasting antidepressant-like effect. Notably, we found that P2X2 protein levels were significantly lower in the DRN of patients with MDD than that of control subjects. Together, these findings elucidate the molecular mechanism underlying IHHT promoting psychological resilience and highlight enhancing HIF-1α–P2X2 signaling in DRN5−HT neurons as a potential avenue for screening novel therapeutic treatments for MDD.

The effects of intermittent hypoxic training on the aerobic capacity of exercisers: a systemic review and meta-analysis

ObjectiveTo systematically review the effects of intermittent hypoxic training on the aerobic capacity of exercisers.MethodsPubMed, Embase, The Cochrane Library, and Web of Science databases were electronically searched to collect studies on the effects of intermittent hypoxic training on the aerobic capacity of exercisers from January 1, 2000, to January 12, 2023. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. Then, meta-analysis was performed by using Stata SE 16.0 software.ResultsA total of 19 articles from 27 studies were included. The results of the meta-analysis showed that compared with the control group, the intermittent hypoxic training group had significantly increased maximal oxygen uptake [weighted mean difference = 3.20 (95%CI: 1.33 ~ 5.08)] and hemoglobin [weighted mean difference = 0.25 (95%CI: 0.04 ~ 0.45)].ConclusionIntermittent hypoxic training can significantly improve the aerobic capacity of exercisers. Due to the limited quantity and quality of the included studies, more high-quality studies are needed to verify the above conclusion.

Effects of Different Protocols of Moderate-Intensity Intermittent Hypoxic Training on Mental Health and Quality of Life in Brazilian Adults Recovered from COVID-19: The AEROBICOVID Double-Blind Randomized Controlled Study

The aim of this study was to investigate the effects of different protocols of moderate-intensity intermittent hypoxic training in patients who had recovered from COVID-19 on quality of life (QoL) and mental health. The sample of this clinical trial-controlled double-blind study consisted of 67 participants aged 30–69 years, who were organized randomly according to Normoxia, Hypoxia, Hypoxia Recovery or Control Group. Eight weeks of cycle ergometer training were performed with a frequency of three training sessions per week in normoxic or hypoxic conditions (with or without hypoxic recovery). Health-related QoL and Mental Health Status were evaluated by 12-Item Short Form Survey and Depression Anxiety and Stress Scale instruments, respectively. All training groups improved the QoL’s physical dimensions (Baseline–Post: Normoxia Group 42.1 (11.0)–48.7 (7.0), Hypoxia Group 46.9 (11.8)–53.5 (6.6) and Hypoxia Recovery Group 45.8 (9.2)–51.1 (5.3)) and mental dimensions (Baseline–Post: Normoxia Group 48.8 (7.9)–54.6 (4.6), Hypoxia Group 45.2 (7.7)–53.2 (3.8) and Hypoxia Recovery Group 46.5 (9.7)–52.0 (9.9)). Regarding mental health outcomes, all training groups decreased depressive symptoms (66.7% Normoxia, 31.2% Hypoxia Recovery and 31% Hypoxia groups), anxiety symptoms (46.5% Normoxia, 45.9% Hypoxia Recovery and 39.5% in the Hypoxia groups) and stress symptoms (40.6% Normoxia, 36.3% Hypoxia Recovery and 22.1% Hypoxia groups). Significant statistical difference was not found between groups. Normoxic and hypoxic training showed a similar effect on QoL and the mental health of Brazilian adults who had recovered from COVID-19.

Intermittent hypoxia training effectively protects against cognitive decline caused by acute hypoxia exposure.

Intermittent hypoxia training (IHT) is a promising approach that has been used to induce acclimatization to hypoxia and subsequently lower the risk of developing acute mountain sickness (AMS). However, the effects of IHT on cognitive and cerebrovascular function after acute hypoxia exposure have not been characterized. In the present study, we first confirmed that the simplified IHT paradigm was effective at relieving AMS at 4300m. Second, we found that IHT improved participants' cognitive and neural alterations when they were exposed to hypoxia. Specifically, impaired working memory performance, decreased conflict control function, impaired cognitive control, and aggravated mental fatigue induced by acute hypoxia exposure were significantly alleviated in the IHT group. Furthermore, a reversal of brain swelling induced by acute hypoxia exposure was visualized in the IHT group using magnetic resonance imaging. An increase in cerebral blood flow (CBF) was observed in multiple brain regions of the IHT group after hypoxia exposure as compared with the control group. Based on these findings, the simplified IHT paradigm might facilitate hypoxia acclimatization, alleviate AMS symptoms, and increase CBF in multiple brain regions, thus ameliorating brain swelling and cognitive dysfunction.

THE EFFECTS OF VARIOUS MODES OF INTERVAL HYPOXIC TRAINING IN EXPERIMENTAL MODELS OF ANXIETY AND DEPRESSION IN RATS

The development of non-drug methods for correcting stress-induced disorders and improving adaptation to stressful factors remains an urgent task of physiology, which has a great translational potential. Previously, we proposed effective methods of hypoxic hypobaric preconditioning and distant ischemic conditioning in this regard. The purpose of this work was to transfer the principles of preconditioning to the approaches of normobaric intermittent hypoxic training (IHT). The effects of five new IHT regimens (3 five-minute sessions of hypoxia of 16% O2 per day, 3 sessions of 12% O2, 7 sessions of 12% O2, 15 sessions of 12% O2, 3 sessions of 9% O2) were studied in experimental models of depression and post-traumatic stress disorder in rats. The preconditioning regime of high intensity 3x9%O2 had the most pronounced antidepressant and anxiolytic effect in models of both pathologies. With a decrease in the level of hypoxia to 12% O2, IHT regimens partially retained their effectiveness with an increase in the number of sessions. The training regime of the longest duration – 15 × 12%O2, was effective in correcting the formation of experimental depression. The intermediate regime – 7 × 12%O2, had an anxiolytic effect, while the preconditioning regime of medium intensity – 3 × 12%O2, demonstrated both an antidepressant and anxiolytic effect. The results indicate that the intensity of hypoxic exposure had the greatest impact on the effectiveness. At the same time, a decrease in the intensity to 16% O2 led to a weakening or loss of stress-protective properties. With regard to the 3 × 9%O2 regime as the most promising, it is advisable to conduct further studies to identify the molecular mechanisms that implement its stress-protective and anxiolytic effects.

Effect of 4-week intermittent hypoxic exercise training for repeated vertical jump performance in untrained males.

To be successful in sports, it is critical to maintain a high level of muscular power throughout a game. Physiological adaptations induced by hypoxic exercise training would provide benefits for fatigue-resisting ability during repeated explosive exercise. The aim of this study was to determine whether a 4-week intermittent hypoxic exercise training program is more effective in improving power endurance during repeated vertical jumps (VJs) when compared with a normoxic counterpart. Eighteen young adult males were divided into two training groups: 1) normoxic training group (NT, FiO<inf>2</inf>: 20.9%, N.=9); and 2) hypoxic training group (HT, FiO<inf>2</inf>: 13.7%, N.=9). For both NT and HT, participants performed three sessions per week for four weeks. Each session consisted of a 60-min exercise session including strength and power training. A repeated VJ (40 reps/set, 2 sets with 5 min rest given between them) was performed before and after the training (pretraining and post-training). The HT group displayed an improvement in repeated VJ performance in a later phase of set 1 following the training (25-30 rep: pretraining 26.49±6.20 vs. post-training 30.55±5.37cm, P=0.0285; 30-35 rep: pretraining 25.08±5.29 vs. post-training 29.56±5.37cm, P=0.0064; 35-40 rep: pretraining 25.05±5.51 vs. post-training 29.28±5.71cm, P=0.0161). In set 2, repeated VJ performance in the later phase was also enhanced in HT following the training (P<0.05 for all). No changes in repeated VJ performance were seen in NT following the training (P>0.05 for all). Also, the HT group showed a trend towards a decrease in Fatigue Index in set 1 (pretraining 23.51±13.27 vs. Post 11.87±12.51%, P=0.1308) and set 2 (pretraining 29.11±13.66 vs. post-training 17.81±17.97%, P=0.1588) following the training. Hypoxic exercise training can be an effective training modality to improve fatigue-resisting ability during repeated explosive exercise.

CARDIOGRAPHIC CHANGES IN ACUTE HYPOXIA AFTER INTERMITTENT HYPOXIC TRAINING IN HUMANS

One of the important areas of research in physiology and medicine is the impact of intermittent hypoxic training on human resistance to exogenous and endogenous environmental factors. Special attention is also paid to cardiac activity.&#x0D; The aim of the paper is to examine the nature and conjugation of human heart bioelectrical processes in acute hypoxia after intermittent hypoxic training.&#x0D; Materials and methods. A 20-minute test with acute hypoxia (AH – 12.3 % O2) was conducted on 29 males, aged 20.2±0.31, at different periods after 16-day-hypoxic training. Blood saturation (SpO2%), amplitude and time ECG parameters were determined.&#x0D; Results. At rest, at certain periods after hypoxic training, we observed an increase in R-R (Day 1, p=0.020), Q-T (Day 1, p=0.005; Day 16, p=0.043) and a decrease in P-Q (Day 7, p= 0.016) compared to the control. In case of acute hypoxia there was a decrease in P1II (Day 1, p=0.019; Day 7, p&lt;0.001; Day 16, p=0.003), P-Q (Day 1, p=0.025; Day 7, p =0.002), PQc and QTc (p&lt;0.001), but an increase in T1II (Day 1, p&lt;0.001; Day 7, p=0.005; Day 16, p=0.010), R-R (Day 1, p&lt;0.001; Day 7, p=0.029; Day 16, p=0.002) and Q-T (Day 1, p&lt;0.001; Day 7, p&lt;0.001; Day 16, p&lt;0.001) compared to the control. According to the period after hypoxic training, we observed the dominance of the factor load R-R, Q-T and P1II, T1II, as well as an increase in the canonical correlation of P1II, RII and T1II with R-R and Q-T.&#x0D; Conclusion. Intermittent hypoxic training leads to an increase in R-R duration, electrical ventricular systole and a decrease in atrioventricular conduction at rest. In case of acute hypoxia in the period after hypoxic training, all ECG parameters (besides maximum ventricular depolarization) change significantly compared &#x0D; to the control. The paper discusses the factorial significance and the degree of conjugation of bathmotropic and dromotropic cardiac processes.

Optimal type and dose of hypoxic training for improving maximal aerobic capacity in athletes: a systematic review and Bayesian model-based network meta-analysis.

Objective: This study aimed to compare and rank the effect of hypoxic practices on maximum oxygen consumption (VO2max) in athletes and determine the hypoxic dose-response correlation using network meta-analysis. Methods: The Web of Science, PubMed, EMBASE, and EBSCO databases were systematically search for randomized controlled trials on the effect of hypoxc interventions on the VO2max of athletes published from inception until 21 February 2023. Studies that used live-high train-high (LHTH), live-high train-low (LHTL), live-high, train-high/low (HHL), intermittent hypoxic training (IHT), and intermittent hypoxic exposure (IHE) interventions were primarily included. LHTL was further defined according to the type of hypoxic environment (natural and simulated) and the altitude of the training site (low altitude and sea level). A meta-analysis was conducted to determine the standardized mean difference between the effects of various hypoxic interventions on VO2max and dose-response correlation. Furthermore, the hypoxic dosage of the different interventions were coordinated using the "kilometer hour" model. Results: From 2,072 originally identified titles, 59 studies were finally included in this study. After data pooling, LHTL, LHTH, and IHT outperformed normoxic training in improving the VO2max of athletes. According to the P-scores, LHTL combined with low altitude training was the most effective intervention for improving VO2max (natural: 0.92 and simulated: 0.86) and was better than LHTL combined with sea level training (0.56). A reasonable hypoxic dose range for LHTH (470-1,130kmh) and HL (500-1,415kmh) was reported with an inverted U-shaped curve relationship. Conclusion: Different types of hypoxic training compared with normoxic training serve as significant approaches for improving aerobic capacity in athletes. Regardless of the type of hypoxic training and the residential condition, LHTL with low altitude training was the most effective intervention. The characteristics of the dose-effect correlation of LHTH and LHTL may be associated with the negative effects of chronic hypoxia.

Effects of Intermittent Hypoxic Training on Aerobic Capacity and Second Ventilatory Threshold in Untrained Men

The aim of study was to evaluate the effects of interval training performed in hypoxia on aerobic capacity and second ventilatory threshold in young, untrained men. Participants (n = 48) were randomly divided into a control group and two groups performing the same interval training (three times a week for 4 weeks) in normoxia (200 m asl) (NT) and in hypoxia (IHT) (3000 m asl, FIO2 = 14.4%). In the incremental test, maximal oxygen uptake (VO2max) was measured and the first (VT1) and second (VT2) ventilatory thresholds and the maximal power output (Pmax) were determined for each participant. The training workloads of the efforts corresponded to the workload at VT2 (effort) and VT1 (active recovery). Training in both normoxia and hypoxia significantly increased absolute VO2max (p = 0.02, ES = 0.51 and p = 0.002, ES = 0.47, respectively). In comparison to NT, only IHT significantly (p &lt; 0.001; ES = 0.80) improved Pmax, as well as power at VT2 (p = 0.02; ES = 0.78). The applied IHT was effective in improving Pmax and power at VT2, which was not observed after training in normoxia.

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

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.