Is Hypoxic/Altitude Training an Important Topic in the Field of Hypoxia?

Hypoxia is an essential topic in medical or biological sciences. The main aims of the present study were to examine the most important medical articles (i.e., the top 100 most cited) on hypoxia. We examine how the Nobel-prize awarded hypoxia inducible factor (HIF)-pathway discovery in the early 1990s has changed the thematic composition of this body of literature, with a special emphasis on the studies linking hypoxia and cancer. We searched Pubmed for articles with the terms #Hypox, #Altitude, or #Mountain in the title that have been published in biomedical journals and ranked the articles on their number of citations in Web of Science. A second search was performed in all journals for articles related to hypoxia and cancer. Strikingly, only 12 of the top-100 most-cited articles on hypoxia and only 3 articles of the top-100 articles related to cancer were published before 1995. Moreover, only 5 articles from prior 1995 reached 1000 citations, while 27 articles published in 1995 or later were cited more than 1000 times, most of them on the HIF-1 pathway. Eighty percent of the top-100 articles were related to the HIF pathway, while there were no articles on the application of hypoxia either for therapeutic use (i.e., hypoxic conditioning in patients) or for performance enhancement (i.e., altitude training in athletes). In conclusion, the early-1990s discovery of the HIF pathway and of its molecular regulation has shifted the focus of hypoxia research towards molecular mechanisms and consequences of tissue hypoxia, most notably in cancer. The importance of studies focusing on clinical and performance applications of systemic hypoxia is relatively lower.

Acute Exposure to Normobaric Hypoxia Impairs Balance Performance in Sub-elite but Not Elite Basketball Players

Although high and simulated altitude training has become an increasingly popular training method, no study has investigated the influence of acute hypoxic exposure on balance in team-sport athletes. Therefore, the purpose of this study was to investigate whether acute exposure to normobaric hypoxia is detrimental to balance performance in highly-trained basketball players. Nine elite and nine sub-elite male basketball players participated in a randomized, single-blinded, cross-over study. Subjects performed repeated trials of a single-leg balance test (SLBT) in an altitude chamber in normoxia (NOR; approximately sea level) with FiO2 20.9% and PiO2 ranging from 146.7 to 150.4 mmHg and in normobaric hypoxia (HYP; ~3,800 m above sea level) with FiO2 13.0% and PiO2 ranging from 90.9 to 94.6 mmHg. The SLBT was performed three times: 15 min after entering the environmental chamber in NOR or HYP, then two times more interspersed by 3-min rest. Peripheral oxygen saturation (SpO2) and heart rate (HR) were recorded at four time points: after the initial 15-min rest inside the chamber and immediately after each SLBT. Across the cohort, the balance performance was 7.1% better during NOR than HYP (P < 0.01, ηp2 = 0.58). However, the performance of the elite group was not impaired by HYP, whereas the sub-elite group performed worse in the HYP condition on both legs (DL: P = 0.02, d = 1.23; NDL: P = 0.01, d = 1.43). SpO2 was lower in HYP than NOR (P < 0.001, ηp2 = 0.99) with a significant decline over time during HYP. HR was higher in HYP than NOR (P = 0.04, ηp2 = 0.25) with a significant increase over time. Acute exposure to normobaric hypoxia detrimentally affected the balance performance in sub-elite but not elite basketball players.

The Modifications of Haemoglobin, Erythropoietin Values and Running Performance While Training at Mountain vs. Hilltop vs. Seaside

Altitude training increases haemoglobin, erythropoietin values among athletes, but may have negative physiological consequences. An alternative, although less explored, that has the potential to positively influence performance while avoiding some of the negative physiological consequences of hypoxia is sand training. Ten endurance-trained athletes (age: 20.8 ± 1.4, body mass: 57.7 ± 8.2 kg, stature: 176 ± 6 cm; 5000 m 14:55.00 ± 0:30 min) performed three 21-day training camps at different locations: at a high altitude (HIGH), at the sea-level (CTRL), at the sea-level on the sand (SAND). Differences in erythropoietin (EPO) and haemoglobin (Hb) concentration, body weight, VO2max and maximal aerobic velocity (VMA) before and after each training cycle were compared. Data analysis has indicated that training during HIGH elicited a greater increase in VO2max (2.4 ± 0.2%; p = 0.005 and 1.0 ± 0.2%; p < 0.001) and VMA (2.4 ± 0.2%, p < 0.001 and 1.2 ± 0.2%; p = 0.001) compared with CTRL and SAND. While increases in VO2max and VMA following SAND were greater (1.3 ± 0.1%; p < 0.001 and 1.2 ± 0.1%; p < 0.001) than those observed after CTRL. Moreover, EPO increased to a greater extent following HIGH (25.3 ± 2.7%) compared with SAND (11.7 ± 1.6%, p = 0.008) and CTRL (0.1 ± 0.3%, p < 0.001) with a greater increase (p < 0.01) following SAND compared with CTRL. Furthermore, HIGH and SAND elicited a greater increase (4.9 ± 0.9%; p = 0.001 and 3.3 ± 1.1%; p = 0.035) in Hb compared with CTRL. There was no difference in Hb changes observed between HIGH and SAND (p = 1.0). Finally, athletes lost 2.1 ± 0.4% (p = 0.001) more weight following HIGH vs. CTRL, while there were no differences in weight changes between HIGH vs. SAND (p = 0.742) and SAND vs. CTRL (p = 0.719). High-altitude training and sea-level training on sand resulted in significant improvements in EPO, Hb, VMA, and VO2max that exceeded changes in such parameters following traditional sea-level training. While high-altitude training elicited greater relative increases in EPO, VMA, and VO2max, sand training resulted in comparable increases in Hb and may prevent hypoxia-induced weight loss.

The Use of a Smartphone Application in Monitoring HRV during an Altitude Training Camp in Professional Female Cyclists: A Preliminary Study

Altitude training is a common strategy to improve performance in endurance athletes. In this context, the monitoring of training and the athletes’ response is essential to ensure positive adaptations. Heart rate variability (HRV) has been proposed as a tool to evaluate stress and the response to training. In this regard, many smartphone applications have emerged allowing a wide access to recording HRV easily. The purpose of this study was to describe the changes of HRV using a validated smartphone application before (Pre-TC), during (TC), and after (Post-TC) an altitude training camp in female professional cyclists. Training load (TL) and vagal markers of heart rate variability (LnRMSSD, LnRMSSDcv) of seven professional female cyclists before, during, and after and altitude training camp were monitored. Training volume (SMD = 0.80), LnRMSSD (SMD = 1.06), and LnRMSSDcv (SMD = −0.98) showed moderate changes from Pre-TC to TC. Training volume (SMD = 0.74), TL (SMD = 0.75), LnRMSSD (SMD = −1.11) and LnRMSSDcv (SMD = 0.83) showed moderate changes from TC to Post-TC. Individual analysis showed that heart rate variability responded differently among subjects. The use of a smartphone application to measure HRV is a useful tool to evaluate the individual response to training in female cyclists.

Neuromuscular Adaptations after an Altitude Training Camp in Elite Judo Athletes

The aim of this study was to investigate neuromuscular adaptations in elite judo athletes after three weeks of power-oriented strength training at terrestrial altitude (2320 m). Nineteen men were assigned to altitude training (AL) (22.1 ± 2.3 years) and sea level training (SL) (22.6 ± 4.1 years). Neuromuscular assessment consisted of: (1) maximal isometric knee extensor (KE) torque, (2) KE rate of torque development (RTD), (3) quadriceps activity and voluntary activation, (4) soleus H-reflex, (5) quadriceps single (TTW) and double twitch torque (TDB100) and contraction time (CTTW). There were no significant differences between groups at baseline for any of the observed parameters. Significant differences were found between groups in terms of change in RTD (p = 0.04). Cohen’s d showed a positive significant effect (0.43) in the SL group and a negative significant effect (−0.58) in the AL group. The difference between groups in changes in CTTW as a function of altitude was on the edge of significance (p = 0.077). CTTW increased by 8.1 ± 9.0% in the AL group (p = 0.036) and remained statistically unchanged in the SL group. Only the AL group showed a relationship between changes in TTW and TDB100 and changes in RTD at posttest (p = 0.022 and p = 0.016, respectively). Altitude induced differences in muscular adaptations likely due to greater peripheral fatigue.

Effects of genetic factors on high altitude training performance

High altitude is considered to be 1800-6000 meters. With the decrease of atmospheric pressure at this altitude, adequate oxygenation cannot be achieved in the tissues and hypoxia develops in the circulatory system. Athletes aim to provide superior performance by training in hypoxic conditions. Varying adaptations in hypobaric hypoxia environments by geographically separated populations represent well-trained specimens that may be relevant to endurance performance. While inhabitants of the Andes show higher levels of hemoglobin and saturation than Tibetans at similar altitude, Ethiopian climbers maintain oxygen delivery despite the hemoglobin levels and saturation typical in sea level ranges. It can also be predicted a significant relationship between the angiotensin converting enzyme (ACE) genotype, which affects metabolic efficiency and performance in hypoxic environments (high altitude). One of the genes that develop at high altitude and occur in response to hypoxia is the hypoxia inducible factor 1 alpha (HIF-1α) gene encoded by the hypoxia inducible factor (HIF-1A) gene. The vascular endothelial growth factor (VEGF-A) gene, which is another gene with angiogenetic factor produced in response to hypoxia, is revealed by the transcription of the HIF-1 alpha gene. Genetic heritage, environmental factors, and the character of exercise loads applied within the framework of lifestyle, neuromuscular development, balanced nutrition, and cultural differences that trigger athletic success may reveal individual changes or differences. Considering all these variables, monitoring and control of performance improvement and athletic achievement graph may become more predictable.

Periodization and Programming for Individual 400 m Medley Swimmers

Knowledge in the scientific domain of individual medley (IM) swimming training over a competitive season is limited. The purpose of this study was to propose a detailed coaching framework incorporating the key elements of a periodized training regimen for a 400 m IM swimmer. This framework was based on the available coaching and scientific literature and the practical experience and expertise of the collaborating authors. The season has been divided in two or three macrocycles, further divided in three mesocycles each (six or nine mesocycles in total), in alignment with the two or three main competitions in each macrocycle. The principal training contents to develop during the season expressed in blood lactate zones are: aerobic training (~2 mmol·L−1), lactate threshold pace (~4 mmol·L−1) and VO2max (maximum oxygen uptake) (~6 mmol·L−1). Strength training should focus on maximum strength, power and speed endurance during the season. Altitude training camps can be placed strategically within the training season to promote physiological adaptation and improvements in performance. A well-constructed technical framework will permit development of training strategies for the 400 m IM swimmer to improve both training and competitive performance.

Influence of Altitude Training on Brain Natriuretic Peptide and Atrial Natriuretic Peptide in Japanese Collegiate Swimmers

Objective and method: To examine the effect of altitude swimming training on BNP (Brain natriuretic peptide) and ANP (Atrial Natriuretic Peptide) levels, and evaluate if BNP and ANP can be hemodynamic markers of hypoxia- and traininginduced stress, Ten collegiate swimmers (Tr) who participated in the altitude training camp at 1900m and 5 healthy subjects (Con) were participated in this study. Blood samples were obtained before the training (day0: Pre), during the training (day5: T1, 10: T2, 16: T3), and after the training (5th after descent: Post). Results: Chronologically, BNP of Tr decreased immediately after ascent and increased thereafter, however the changes were not significant. ANP levels were almost unchanged in Tr, whereas there was an increase at T1 in Con compared with Tr (P<0.05). BNP/ANP ratio was significantly higher in Tr (P<0.05) than Con at T3. The results of our study indicate that swimming training at an altitude of 1900m may influence ANP and BNP in the different way, and the stimuli of training is dominant to the hypoxic stress. Conclusion: Our results suggest that we can evaluate the training and hypoxic stress based on natriuretic peptide levels, and predict the hemodynamics or dehydration state by monitoring the natriuretic peptide levels during altitude training

Endurance Is Improved in Female Rats After Living High-Training High Despite Alterations in Skeletal Muscle

Altitude camps are used during the preparation of endurance athletes to improve performance based on the stimulation of erythropoiesis by living at high altitude. In addition to such whole-body adaptations, studies have suggested that high-altitude training increases mitochondrial mass, but this has been challenged by later studies. Here, we hypothesized that living and training at high altitude (LHTH) improves mitochondrial efficiency and/or substrate utilization. Female rats were exposed and trained in hypoxia (simulated 3,200 m) for 5 weeks (LHTH) and compared to sedentary rats living in hypoxia (LH) or normoxia (LL) or those that trained in normoxia (LLTL). Maximal aerobic velocity (MAV) improved with training, independently of hypoxia, whereas the time to exhaustion, performed at 65% of MAV, increased both with training (P = 0.009) and hypoxia (P = 0.015), with an additive effect of the two conditions. The distance run was 7.98 ± 0.57 km in LHTH vs. 6.94 ± 0.51 in LLTL (+15%, ns). The hematocrit increased &gt;20% with hypoxia (P &lt; 0.001). The increases in mitochondrial mass and maximal oxidative capacity with endurance training were blunted by combination with hypoxia (−30% for citrate synthase, P &lt; 0.01, and −23% for Vmax glut−succ, P &lt; 0.001 between LHTH and LLTL). A similar reduction between the LHTH and LLTL groups was found for maximal respiration with pyruvate (−29%, P &lt; 0.001), for acceptor-control ratio (−36%, hypoxia effect, P &lt; 0.001), and for creatine kinase efficiency (−48%, P &lt; 0.01). 3-hydroxyl acyl coenzyme A dehydrogenase was not altered by hypoxia, whereas maximal respiration with Palmitoyl-CoA specifically decreased. Overall, our results show that mitochondrial adaptations are not involved in the improvement of submaximal aerobic performance after LHTH, suggesting that the benefits of altitude camps in females relies essentially on other factors, such as the transitory elevation of hematocrit, and should be planned a few weeks before competition and not several months.