51
|
Saugy JJ, Schmitt L, Cejuela R, Faiss R, Hauser A, Wehrlin JP, Rudaz B, Delessert A, Robinson N, Millet GP. Comparison of "Live High-Train Low" in normobaric versus hypobaric hypoxia. PLoS One 2014; 9:e114418. [PMID: 25517507 PMCID: PMC4269399 DOI: 10.1371/journal.pone.0114418] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 11/10/2014] [Indexed: 11/18/2022] Open
Abstract
We investigated the changes in both performance and selected physiological parameters following a Live High-Train Low (LHTL) altitude camp in either normobaric hypoxia (NH) or hypobaric hypoxia (HH) replicating current "real" practices of endurance athletes. Well-trained triathletes were split into two groups (NH, n = 14 and HH, n = 13) and completed an 18-d LHTL camp during which they trained at 1100-1200 m and resided at an altitude of 2250 m (PiO2 = 121.7±1.2 vs. 121.4±0.9 mmHg) under either NH (hypoxic chamber; FiO2 15.8±0.8%) or HH (real altitude; barometric pressure 580±23 mmHg) conditions. Oxygen saturations (SpO2) were recorded continuously daily overnight. PiO2 and training loads were matched daily. Before (Pre-) and 1 day after (Post-) LHTL, blood samples, VO2max, and total haemoglobin mass (Hb(mass)) were measured. A 3-km running test was performed near sea level twice before, and 1, 7, and 21 days following LHTL. During LHTL, hypoxic exposure was lower for the NH group than for the HH group (220 vs. 300 h; P<0.001). Night SpO2 was higher (92.1±0.3 vs. 90.9±0.3%, P<0.001), and breathing frequency was lower in the NH group compared with the HH group (13.9±2.1 vs. 15.5±1.5 breath.min(-1), P<0.05). Immediately following LHTL, similar increases in VO2max (6.1±6.8 vs. 5.2±4.8%) and Hb(mass) (2.6±1.9 vs. 3.4±2.1%) were observed in NH and HH groups, respectively, while 3-km performance was not improved. However, 21 days following the LHTL intervention, 3-km run time was significantly faster in the HH (3.3±3.6%; P<0.05) versus the NH (1.2±2.9%; ns) group. In conclusion, the greater degree of race performance enhancement by day 21 after an 18-d LHTL camp in the HH group was likely induced by a larger hypoxic dose. However, one cannot rule out other factors including differences in sleeping desaturations and breathing patterns, thus suggesting higher hypoxic stimuli in the HH group.
Collapse
Affiliation(s)
- Jonas J. Saugy
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Laurent Schmitt
- National School of Mountain Sports/National Ski-Nordic Centre, Prémanon, France
| | - Roberto Cejuela
- Departmental Section of Physical Education and Sports, University of Alicante, Alicante, Spain
| | - Raphael Faiss
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Anna Hauser
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Swiss Federal Institute of Sport, Magglingen, Switzerland
| | - Jon P. Wehrlin
- Swiss Federal Institute of Sport, Magglingen, Switzerland
| | - Benjamin Rudaz
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Audric Delessert
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Neil Robinson
- Swiss Laboratory for Doping Analyses, University of Lausanne, Lausanne, Switzerland
| | - Grégoire P. Millet
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- * E-mail:
| |
Collapse
|
52
|
Ryan BJ, Wachsmuth NB, Schmidt WF, Byrnes WC, Julian CG, Lovering AT, Subudhi AW, Roach RC. AltitudeOmics: rapid hemoglobin mass alterations with early acclimatization to and de-acclimatization from 5260 m in healthy humans. PLoS One 2014; 9:e108788. [PMID: 25271637 PMCID: PMC4182755 DOI: 10.1371/journal.pone.0108788] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 08/26/2014] [Indexed: 01/09/2023] Open
Abstract
It is classically thought that increases in hemoglobin mass (Hbmass) take several weeks to develop upon ascent to high altitude and are lost gradually following descent. However, the early time course of these erythropoietic adaptations has not been thoroughly investigated and data are lacking at elevations greater than 5000 m, where the hypoxic stimulus is dramatically increased. As part of the AltitudeOmics project, we examined Hbmass in healthy men and women at sea level (SL) and 5260 m following 1, 7, and 16 days of high altitude exposure (ALT1/ALT7/ALT16). Subjects were also studied upon return to 5260 m following descent to 1525 m for either 7 or 21 days. Compared to SL, absolute Hbmass was not different at ALT1 but increased by 3.7±5.8% (mean ± SD; n = 20; p<0.01) at ALT7 and 7.6±6.6% (n = 21; p<0.001) at ALT16. Following descent to 1525 m, Hbmass was reduced compared to ALT16 (−6.0±3.7%; n = 20; p = 0.001) and not different compared to SL, with no difference in the loss in Hbmass between groups that descended for 7 (−6.3±3.0%; n = 13) versus 21 days (−5.7±5.0; n = 7). The loss in Hbmass following 7 days at 1525 m was correlated with an increase in serum ferritin (r = −0.64; n = 13; p<0.05), suggesting increased red blood cell destruction. Our novel findings demonstrate that Hbmass increases within 7 days of ascent to 5260 m but that the altitude-induced Hbmass adaptation is lost within 7 days of descent to 1525 m. The rapid time course of these adaptations contrasts with the classical dogma, suggesting the need to further examine mechanisms responsible for Hbmass adaptations in response to severe hypoxia.
Collapse
Affiliation(s)
- Benjamin J. Ryan
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
- * E-mail:
| | - Nadine B. Wachsmuth
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Walter F. Schmidt
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - William C. Byrnes
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Colleen G. Julian
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Andrew T. Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Andrew W. Subudhi
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado, United States of America
| | - Robert C. Roach
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| |
Collapse
|
53
|
Schumacher YO, Garvican LA, Christian R, Lobigs LM, Qi J, Fan R, He Y, Wang H, Gore CJ, Ma F. High altitude, prolonged exercise, and the athlete biological passport. Drug Test Anal 2014; 7:48-55. [DOI: 10.1002/dta.1717] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/10/2014] [Accepted: 08/10/2014] [Indexed: 11/12/2022]
Affiliation(s)
| | - Laura A. Garvican
- Australian Institute of Sports; Department of Physiology; Canberra Australia
- Research Institute for Sport and Exercise; University of Canberra; ACT Australia
| | - Ryan Christian
- Aspetar Orthopedic & Sports Medicine Hospital; PO Box 29222 Doha Qatar
| | - Louisa M. Lobigs
- Aspetar Orthopedic & Sports Medicine Hospital; PO Box 29222 Doha Qatar
| | - Jiliang Qi
- Qinghai Institute of Sports Science (QISS); Duoba National Altitude Training Base; Xining City Qinghai China
| | - Rongyun Fan
- Qinghai Institute of Sports Science (QISS); Duoba National Altitude Training Base; Xining City Qinghai China
| | - Yingying He
- Qinghai Institute of Sports Science (QISS); Duoba National Altitude Training Base; Xining City Qinghai China
| | - Hailing Wang
- Qinghai Institute of Sports Science (QISS); Duoba National Altitude Training Base; Xining City Qinghai China
| | - Christopher J. Gore
- Australian Institute of Sports; Department of Physiology; Canberra Australia
| | - Fuhai Ma
- Qinghai Institute of Sports Science (QISS); Duoba National Altitude Training Base; Xining City Qinghai China
| |
Collapse
|
54
|
Garvican-Lewis LA, Schumacher YO, Clark SA, Christian R, Menaspà P, Plowman J, Stephens B, Qi J, Fan R, He Y, Martin DT, Thompson KG, Gore CJ, Ma F. Stage racing at altitude induces hemodilution despite an increase in hemoglobin mass. J Appl Physiol (1985) 2014; 117:463-72. [DOI: 10.1152/japplphysiol.00242.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Plasma volume (PV) can be modulated by altitude exposure (decrease) and periods of intense exercise (increase). Cycle racing at altitude combines both stimuli, although presently no data exist to document which is dominant. Hemoglobin mass (Hbmass), hemoglobin concentration ([Hb]), and percent reticulocytes (%Retics) of altitude (ALT; n = 9) and sea-level (SL; n = 9) residents were measured during a 14-day cycling race, held at 1,146–4120 m, as well as during a simulated tour near sea level (SIM; n = 12). Hbmass was assessed before and on days 9 and 14 of racing. Venous blood was collected on days 0, 3, 6, 10, and 14. PV was calculated from Hbmass and [Hb]. A repeated-measures ANOVA was used to assess the impact of racing at altitude over time, within and between groups. [Hb] decreased significantly in all groups over time ( P < 0.0001) with decreases evident on the third day of racing. %Retics increased significantly in SL only ( P < 0.0001), with SL values elevated at day 6 compared with prerace ( P = 0.02), but were suppressed by the end of the race ( P = 0.0002). Hbmass significantly increased in SL after 9 ( P = 0.0001) and 14 ( P = 0.008) days of racing and was lower at the end of the race than midrace ( P = 0.018). PV increased in all groups ( P < 0.0001). Multiday cycle racing at altitude induces hemodilution of a similar magnitude to that observed during SL racing and occurs in nonacclimatized SL residents, despite an altitude-induced increase in Hbmass. Osmotic regulatory mechanisms associated with intense exercise appear to supersede acute enhancement of oxygen delivery at altitude.
Collapse
Affiliation(s)
- Laura A. Garvican-Lewis
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
- Physiology, Australian Institute of Sport, Canberra, Australia
| | | | - Sally A. Clark
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Ryan Christian
- Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Paolo Menaspà
- Physiology, Australian Institute of Sport, Canberra, Australia
- Edith Cowan University, Perth, Australia; and
| | - Jamie Plowman
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Brian Stephens
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Jiliang Qi
- Qinghai Institute of Sports Science, Duoba, China
| | - Rongyun Fan
- Qinghai Institute of Sports Science, Duoba, China
| | - Yingying He
- Qinghai Institute of Sports Science, Duoba, China
| | - David T. Martin
- Physiology, Australian Institute of Sport, Canberra, Australia
| | - Kevin G. Thompson
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
| | | | - Fuhai Ma
- Qinghai Institute of Sports Science, Duoba, China
| |
Collapse
|
55
|
Wachsmuth N, Kley M, Spielvogel H, Aughey RJ, Gore CJ, Bourdon PC, Hammond K, Sargent C, Roach GD, Sanchez RS, Claros JCJ, Schmidt WF, Garvican-Lewis LA. Changes in blood gas transport of altitude native soccer players near sea-level and sea-level native soccer players at altitude (ISA3600). Br J Sports Med 2014; 47 Suppl 1:i93-9. [PMID: 24282216 PMCID: PMC3903154 DOI: 10.1136/bjsports-2013-092761] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Objectives The optimal strategy for soccer teams playing at altitude is not known, that is, ‘fly-in, fly-out’ versus short-term acclimatisation. Here, we document changes in blood gas and vascular volumes of sea-level (Australian, n=20) and altitude (Bolivian, n=19) native soccer players at 3600 m. Methods Haemoglobin-oxygen saturation (Hb-sO2), arterial oxygen content (CaO2), haemoglobin mass (Hbmass), blood volume (BV) and blood gas concentrations were measured before descent (Bolivians only), together with aerobic fitness (via Yo-YoIR1), near sea-level, after ascent and during 13 days at 3600 m. Results At baseline, haemoglobin concentration [Hb] and Hbmass were higher in Bolivians (mean±SD; 18.2±1.0 g/dL, 12.8±0.8 g/kg) than Australians (15.0±0.9 g/dL, 11.6±0.7 g/kg; both p≤0.001). Near sea-level, [Hb] of Bolivians decreased to 16.6±0.9 g/dL, but normalised upon return to 3600 m; Hbmass was constant regardless of altitude. In Australians, [Hb] increased after 12 days at 3600 m to 17.3±1.0 g/dL; Hbmass increased by 3.0±2.7% (p≤0.01). BV decreased in both teams at altitude by ∼400 mL. Arterial partial pressure for oxygen (PaO2), Hb-sO2 and CaO2 of both teams decreased within 2 h of arrival at 3600 m (p≤0.001) but increased over the following days, with CaO2 overcompensated in Australians (+1.7±1.2 mL/100 mL; p≤0.001). Yo-YoIR1 was lower on the 3rd versus 10th day at altitude and was significantly related to CaO2. Conclusions The marked drop in PaO2 and CaO2 observed after ascent does not support the ‘fly-in, fly-out’ approach for soccer teams to play immediately after arrival at altitude. Although short-term acclimatisation was sufficient for Australians to stabilise their CaO2 (mostly due to loss of plasma volume), 12 days appears insufficient to reach chronic levels of adaption.
Collapse
Affiliation(s)
- Nadine Wachsmuth
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, , Bayreuth, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
56
|
Buchheit M, Racinais S, Bilsborough J, Hocking J, Mendez-Villanueva A, Bourdon PC, Voss S, Livingston S, Christian R, Périard J, Cordy J, Coutts AJ. Adding heat to the live-high train-low altitude model: a practical insight from professional football. Br J Sports Med 2014; 47 Suppl 1:i59-69. [PMID: 24282209 PMCID: PMC3903152 DOI: 10.1136/bjsports-2013-092559] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Objectives To examine with a parallel group study design the performance and physiological responses to a 14-day off-season ‘live high-train low in the heat’ training camp in elite football players. Methods Seventeen professional Australian Rules Football players participated in outdoor football-specific skills (32±1°C, 11.5 h) and indoor strength (23±1°C, 9.3 h) sessions and slept (12 nights) and cycled indoors (4.3 h) in either normal air (NORM, n=8) or normobaric hypoxia (14±1 h/day, FiO2 15.2–14.3%, corresponding to a simulated altitude of 2500–3000 m, hypoxic (HYP), n=9). They completed the Yo-Yo Intermittent Recovery level 2 (Yo-YoIR2) in temperate conditions (23±1°C, normal air) precamp (Pre) and postcamp (Post). Plasma volume (PV) and haemoglobin mass (Hbmass) were measured at similar times and 4 weeks postcamp (4WPost). Sweat sodium concentration ((Na+)sweat) was measured Pre and Post during a heat-response test (44°C). Results Both groups showed very large improvements in Yo-YoIR2 at Post (+44%; 90% CL 38, 50), with no between-group differences in the changes (−1%; −9, 9). Postcamp, large changes in PV (+5.6%; −1.8, 5.6) and (Na+)sweat (−29%; −37, −19) were observed in both groups, while Hbmass only moderately increased in HYP (+2.6%; 0.5, 4.5). At 4WPost, there was a likely slightly greater increase in Hbmass (+4.6%; 0.0, 9.3) and PV (+6%; −5, 18, unclear) in HYP than in NORM. Conclusions The combination of heat and hypoxic exposure during sleep/training might offer a promising ‘conditioning cocktail’ in team sports.
Collapse
Affiliation(s)
- M Buchheit
- Physiology Unit, Football Performance and Science Department, ASPIRE, Academy for Sports Excellence, , Doha, Qatar
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
57
|
Garvican-Lewis LA, Clark SA, Polglaze T, McFadden G, Gore CJ. Ten days of simulated live high:train low altitude training increases Hbmass in elite water polo players. Br J Sports Med 2014; 47 Suppl 1:i70-3. [PMID: 24282211 PMCID: PMC3903155 DOI: 10.1136/bjsports-2013-092746] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Objectives Water polo requires high aerobic power to meet the demands of match play. Live high:train low (LHTL) may enhance aerobic capacity at sea level. Before the Olympics, the Australian women's water polo team utilised LHTL in an attempt to enhance aerobic fitness. Methods Over 6 months, 11 players completed three normobaric LHTL exposures (block 1:11 days at 3000 m; block 2+3:9 days at 2500 m, 11 days normoxia, 10 days at 2800 m). Haemoglobin mass (Hbmass) was measured through carbon monoxide-rebreathing. Before each block, the relationship between Hbmass and water polo-specific aerobic fitness was investigated using the Multistage Shuttle Swim Test (MSST). Effect size statistics were adopted with likely, highly likely and almost certainly results being >75%, >95%, >99%, respectively. A Pearson product moment correlation was used to characterise the association between pooled data of Hbmass and MSST. Results Hbmass (mean±SD, pre 721±66 g) likely increased after block 1 and almost certainly after block 2+3 (% change; 90% confidence limits: block 1: 3.7%; 1.3–6.2%, block 2+3: 4.5%; 3.8–5.1%) and the net effect was almost certainly higher after block 2+3 than before block 1 (pre) by 8.5%; 7.3–9.7%. There was a very large correlation between Hbmass (g/kg) and MSST score (r=0.73). Conclusions LHTL exposures of <2 weeks induced approximately 4% increase in Hbmass of water polo players. Extra Hbmass may increase aerobic power, but since match performance is nuanced by many factors it is impossible to ascertain whether the increased Hbmass contributed to Australia's Bronze medal.
Collapse
|
58
|
McLean BD, Buttifant D, Gore CJ, White K, Kemp J. Year-to-year variability in haemoglobin mass response to two altitude training camps. Br J Sports Med 2014; 47 Suppl 1:i51-8. [PMID: 24282208 PMCID: PMC3903153 DOI: 10.1136/bjsports-2013-092744] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Aim To quantify the year-to-year variability of altitude-induced changes in haemoglobin mass (Hbmass) in elite team-sport athletes. Methods 12 Australian-Footballers completed a 19-day (ALT1) and 18-day (ALT2) moderate altitude (∼2100 m), training camp separated by 12 months. An additional 20 participants completed only one of the two training camps (ALT1 additional n=9, ALT2 additional n=11). Total Hbmass was assessed using carbon monoxide rebreathing before (PRE), after (POST1) and 4 weeks after each camp. The typical error of Hbmass for the pooled data of all 32 participants was 2.6%. A contemporary statistics analysis was used with the smallest worthwhile change set to 2% for Hbmass. Results POST1 Hbmass was very likely increased in ALT1 (3.6±1.6%, n=19; mean±∼90 CL) as well as ALT2 (4.4±1.3%, n=23) with an individual responsiveness of 1.3% and 2.2%, respectively. There was a small correlation between ALT1 and ALT2 (R=0.21, p=0.59) for a change in Hbmass, but a moderately inverse relationship between the change in Hbmass and initial relative Hbmass (g/kg (R=−0.51, p=0.04)). Conclusions Two preseason moderate altitude camps 1 year apart yielded a similar (4%) mean increase in Hbmass of elite footballers, with an individual responsiveness of approximately half the group mean effect, indicating that most players gained benefit. Nevertheless, the same individuals generally did not change their Hbmass consistently from year to year. Thus, a ‘responder’ or ‘non-responder’ to altitude for Hbmass does not appear to be a fixed trait.
Collapse
Affiliation(s)
- Blake D McLean
- Sport Science Department, Collingwood Football Club, , Melbourne, Victoria, Australia
| | | | | | | | | |
Collapse
|
59
|
Saunders PU, Garvican-Lewis LA, Schmidt WF, Gore CJ. Relationship between changes in haemoglobin mass and maximal oxygen uptake after hypoxic exposure. Br J Sports Med 2014; 47 Suppl 1:i26-30. [PMID: 24282203 PMCID: PMC3903146 DOI: 10.1136/bjsports-2013-092841] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Endurance athletes have been using altitude training for decades to improve near sea-level performance. The predominant mechanism is thought to be accelerated erythropoiesis increasing haemoglobin mass (Hbmass) resulting in a greater maximal oxygen uptake (). Not all studies have shown a proportionate increase in as a result of increased Hbmass. The aim of this study was to determine the relationship between the two parameters in a large group of endurance athletes after altitude training. Methods 145 elite endurance athletes (94 male and 51 female) who participated in various altitude studies as altitude or control participants were used for the analysis. Participants performed Hbmass and testing before and after intervention. Results For the pooled data, the correlation between per cent change in Hbmass and per cent change in was significant (p<0.0001, r2=0.15), with a slope (95% CI) of 0.48 (0.30 to 0.67) intercept free to vary and 0.62 (0.46 to 0.77) when constrained through the origin. When separated, the correlations were significant for the altitude and control groups, with the correlation being stronger for the altitude group (slope of 0.57 to 0.72). Conclusions With high statistical power, we conclude that altitude training of endurance athletes will result in an increase in of more than half the magnitude of the increase in Hbmass, which supports the use of altitude training by athletes. But race performance is not perfectly related to relative , and other non-haematological factors altered from altitude training, such as running economy and lactate threshold, may also be beneficial to performance.
Collapse
Affiliation(s)
- Philo U Saunders
- Department of Physiology, Australian Institute of Sport, , Canberra, Australian Capital Territory, Australia
| | | | | | | |
Collapse
|
60
|
Govus AD, Abbiss CR, Garvican-Lewis LA, Swinkels DW, Laarakkers CM, Gore CJ, Peeling P. Acute hypoxic exercise does not alter post-exercise iron metabolism in moderately trained endurance athletes. Eur J Appl Physiol 2014; 114:2183-91. [DOI: 10.1007/s00421-014-2938-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 06/12/2014] [Indexed: 12/11/2022]
|
61
|
GARVICAN LAURAA, SAUNDERS PHILOU, CARDOSO TANUSHA, MACDOUGALL IAINC, LOBIGS LOUISAM, FAZAKERLEY RUTH, FALLON KIERANE, ANDERSON BEV, ANSON JUDITHM, THOMPSON KEVING, GORE CHRISTOPHERJ. Intravenous Iron Supplementation in Distance Runners with Low or Suboptimal Ferritin. Med Sci Sports Exerc 2014; 46:376-85. [DOI: 10.1249/mss.0b013e3182a53594] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
62
|
Turner G, Pringle JSM, Ingham SA, Fudge BW, Richardson AJ, Maxwell NS. The influence of carbon monoxide bolus on the measurement of total haemoglobin mass using the optimized CO-rebreathing method. Physiol Meas 2014; 35:N11-9. [DOI: 10.1088/0967-3334/35/2/n11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
63
|
Aughey RJ, Buchheit M, Garvican-Lewis LA, Roach GD, Sargent C, Billaut F, Varley MC, Bourdon PC, Gore CJ. Yin and yang, or peas in a pod? Individual-sport versus team-sport athletes and altitude training. Br J Sports Med 2013; 47:1150-4. [PMID: 24255910 PMCID: PMC3841751 DOI: 10.1136/bjsports-2013-092764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2013] [Indexed: 11/04/2022]
Abstract
The question of whether altitude training can enhance subsequent sea-level performance has been well investigated over many decades. However, research on this topic has focused on athletes from individual or endurance sports, with scant number of studies on team-sport athletes. Questions that need to be answered include whether this type of training may enhance team-sport athlete performance, when success in team-sport is often more based on technical and tactical ability rather than physical capacity per se. This review will contrast and compare athletes from two sports representative of endurance (cycling) and team-sports (soccer). Specifically, we draw on the respective competition schedules, physiological capacities, activity profiles and energetics of each sport to compare the similarities between athletes from these sports and discuss the relative merits of altitude training for these athletes. The application of conventional live-high, train-high; live-high, train-low; and intermittent hypoxic training for team-sport athletes in the context of the above will be presented. When the above points are considered, we will conclude that dependent on resources and training objectives, altitude training can be seen as an attractive proposition to enhance the physical performance of team-sport athletes without the need for an obvious increase in training load.
Collapse
Affiliation(s)
- Robert J Aughey
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- Western Bulldogs Football Club, Melbourne, Victoria, Australia
| | - Martin Buchheit
- Sport Science Department, Physiology Unit, ASPIRE Academy for Sports Excellence, Doha, Qatar
| | - Laura A Garvican-Lewis
- Department of Physiology, Australian Institute of Sport, Canberra, Australian Capital Territory, Australia
- National Institute of Sports Studies, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Gregory D Roach
- Appleton Institute for Behavioural Science, Central Queensland University, Adelaide, South Australia, Australia
| | - Charli Sargent
- Appleton Institute for Behavioural Science, Central Queensland University, Adelaide, South Australia, Australia
| | | | - Matthew C Varley
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - Pitre C Bourdon
- Sport Science Department, Physiology Unit, ASPIRE Academy for Sports Excellence, Doha, Qatar
| | - Christopher J Gore
- Department of Physiology, Australian Institute of Sport, Canberra, Australian Capital Territory, Australia
- Exercise Physiology Laboratory, Flinders University, Adelaide, South Australia, Australia
| |
Collapse
|
64
|
Gore CJ, Sharpe K, Garvican-Lewis LA, Saunders PU, Humberstone CE, Robertson EY, Wachsmuth NB, Clark SA, McLean BD, Friedmann-Bette B, Neya M, Pottgiesser T, Schumacher YO, Schmidt WF. Altitude training and haemoglobin mass from the optimised carbon monoxide rebreathing method determined by a meta-analysis. Br J Sports Med 2013; 47 Suppl 1:i31-9. [PMID: 24282204 PMCID: PMC3903147 DOI: 10.1136/bjsports-2013-092840] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2013] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To characterise the time course of changes in haemoglobin mass (Hbmass) in response to altitude exposure. METHODS This meta-analysis uses raw data from 17 studies that used carbon monoxide rebreathing to determine Hbmass prealtitude, during altitude and postaltitude. Seven studies were classic altitude training, eight were live high train low (LHTL) and two mixed classic and LHTL. Separate linear-mixed models were fitted to the data from the 17 studies and the resultant estimates of the effects of altitude used in a random effects meta-analysis to obtain an overall estimate of the effect of altitude, with separate analyses during altitude and postaltitude. In addition, within-subject differences from the prealtitude phase for altitude participant and all the data on control participants were used to estimate the analytical SD. The 'true' between-subject response to altitude was estimated from the within-subject differences on altitude participants, between the prealtitude and during-altitude phases, together with the estimated analytical SD. RESULTS During-altitude Hbmass was estimated to increase by ∼1.1%/100 h for LHTL and classic altitude. Postaltitude Hbmass was estimated to be 3.3% higher than prealtitude values for up to 20 days. The within-subject SD was constant at ∼2% for up to 7 days between observations, indicative of analytical error. A 95% prediction interval for the 'true' response of an athlete exposed to 300 h of altitude was estimated to be 1.1-6%. CONCLUSIONS Camps as short as 2 weeks of classic and LHTL altitude will quite likely increase Hbmass and most athletes can expect benefit.
Collapse
Affiliation(s)
- Christopher J Gore
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
- Exercise Physiology Laboratory, Flinders University, Adelaide, Australia
- University of Canberra, Canberra, Australia
| | - Ken Sharpe
- Department of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - Laura A Garvican-Lewis
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
- University of Canberra, Canberra, Australia
| | - Philo U Saunders
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
- University of Canberra, Canberra, Australia
| | - Clare E Humberstone
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
| | | | - Nadine B Wachsmuth
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Sally A Clark
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
| | - Blake D McLean
- School of Exercise Science, Australian Catholic University, Melbourne, Australia
| | | | - Mitsuo Neya
- Singapore Sports Institute, Singapore Sports Council, Singapore, Singapore
| | | | | | - Walter F Schmidt
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| |
Collapse
|
65
|
Lower running performance and exacerbated fatigue in soccer played at 1600 m. Int J Sports Physiol Perform 2013; 9:397-404. [PMID: 23751901 DOI: 10.1123/ijspp.2012-0375] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE This study investigated the decrement in running performance of elite soccer players competing at low altitude and time course for abatement of these decrements. METHODS Twenty elite youth soccer players had their activity profile, in a sea-level (SL) and 2 altitude (Alt, 1600 m, d 4, and d 6) matches, measured with a global positioning system. Measures expressed in meters per minute of match time were total distance, low- and high-velocity running (LoVR, 0.01-4.16 m/s; HiVR, 4.17-10.0 m/s), and frequency of maximal accelerations (>2.78 m/s2). The peak and subsequent stanza for each measure were identified and a transient fatigue index calculated. Mean heart rate (HR) during the final minute of a submaximal running task (5 min, 11 km/h) was recorded at SL and for 10 d at Alt. Differences were determined between SL and Alt using percentage change and effect-size (ES) statistic with 90% confidence intervals. RESULTS Mean HR almost certainly increased on d 1 (5.4%, ES 1.01 ± 0.35) and remained probably elevated on both d 2 (ES 0.42 ± 0.31) and d3 (ES 0.30 ± 0.25), returning to baseline at d 5. Total distance was almost certainly lower than SL (ES -0.76 ± 0.37) at d 4 and remained probably reduced on d 6 (ES -0.42 ± 0.36). HiVR probably decreased at d 4 vs SL (-0.47 ± 0.59), with no clear effect of altitude at d 6 (-0.08 ± 0.41). Transient fatigue in matches was evident at SL and Alt, with a possibly greater decrement at Alt. CONCLUSION Despite some physiological adaptation, match running performance of youth soccer players is compromised for at least 6 d at low altitude.
Collapse
|
66
|
Abstract
Reticulocytes are young red blood cells which develop from erythroblasts and circulate in the bloodstream for about 1-4 days before maturing into erythrocytes. With the introduction of reticulocyte count in equations and statistical models for detecting suspected blood doping, its application to sports medicine has attracted growing interest in reticulocyte behavior during training and competition seasons in athletes and experimental blood doping treatment in healthy volunteers. An update on recent publications is therefore needed to improve the interpretation of reticulocyte analysis and its variability in sportsmen. Reticulocyte count constitutes a robust parameter during the preanalytical phase, but cell stability can be assured only if blood samples are kept at constantly cold temperatures (4 degrees C) and test results will differ depending on the blood analyzer system used. Marked intraindividual variability is the principal finding to be evaluated when exercise-induced changes are observed or illicit procedures suspected. Furthermore, reticulocyte variability is greater than that of other hematological parameters such as hemoglobin or hematocrit. Ideally, any variation should be interpreted against long-term time series for the individual athlete: values obtained from large athlete cohorts ought to be used only for extrapolating outliers that deserve further examination. Reticulocyte distribution in athletes is similar to that found in the general population, and a gender effect in some sports disciplines or selected athlete groups may be seen. Reticulocyte variability is strongly influenced by seasonal factors linked to training and competition schedules and by the type of sports discipline. Published experimental data have confirmed the high sensitivity of reticulocyte analysis in identifying abnormal bone marrow stimulation by either erythropoietin administration or blood withdrawal and reinfusion.
Collapse
|
67
|
Billaut F, Gore CJ, Aughey RJ. Enhancing team-sport athlete performance: is altitude training relevant? Sports Med 2013; 42:751-67. [PMID: 22845561 DOI: 10.1007/bf03262293] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Field-based team sport matches are composed of short, high-intensity efforts, interspersed with intervals of rest or submaximal exercise, repeated over a period of 60-120 minutes. Matches may also be played at moderate altitude where the lower oxygen partial pressure exerts a detrimental effect on performance. To enhance run-based performance, team-sport athletes use varied training strategies focusing on different aspects of team-sport physiology, including aerobic, sprint, repeated-sprint and resistance training. Interestingly, 'altitude' training (i.e. living and/or training in O(2)-reduced environments) has only been empirically employed by athletes and coaches to improve the basic characteristics of speed and endurance necessary to excel in team sports. Hypoxia, as an additional stimulus to training, is typically used by endurance athletes to enhance performance at sea level and to prepare for competition at altitude. Several approaches have evolved in the last few decades, which are known to enhance aerobic power and, thus, endurance performance. Altitude training can also promote an increased anaerobic fitness, and may enhance sprint capacity. Therefore, altitude training may confer potentially-beneficial adaptations to team-sport athletes, which have been overlooked in contemporary sport physiology research. Here, we review the current knowledge on the established benefits of altitude training on physiological systems relevant to team-sport performance, and conclude that current evidence supports implementation of altitude training modalities to enhance match physical performances at both sea level and altitude. We hope that this will guide the practice of many athletes and stimulate future research to better refine training programmes.
Collapse
Affiliation(s)
- François Billaut
- School of Sport and Exercise Science, Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia.
| | | | | |
Collapse
|
68
|
Physiological and performance responses to a preseason altitude-training camp in elite team-sport athletes. Int J Sports Physiol Perform 2012; 8:391-9. [PMID: 23170749 DOI: 10.1123/ijspp.8.4.391] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE Little research has been done on the physiological and performance effects of altitude training on team-sport athletes. Therefore, this study examined changes in 2000-m time-trial running performance (TT), hemoglobin mass (Hbmass), and intramuscular carnosine content of elite Australian Football (AF) players after a preseason altitude camp. METHODS Thirty elite AF players completed 19 days of living and training at either moderate altitude (~2130 m; ALT, n = 21) or sea level (CON, n = 9). TT performance and Hbmass were assessed preintervention (PRE) and postintervention (POST1) in both groups and at 4 wk after returning to sea level (POST2) in ALT only. RESULTS Improvement in TT performance after altitude was likely 1.5% (± 4.8-90%CL) greater in ALT than in CON, with an individual responsiveness of 0.8%. Improvements in TT were maintained at POST2 in ALT. Hbmass after altitude was very likely increased in ALT compared with CON (2.8% ± 3.5%), with an individual responsiveness of 1.3%. Hbmass returned to baseline at POST2. Intramuscular carnosine did not change in either gastrocnemius or soleus from PRE to POST1. CONCLUSIONS A preseason altitude camp improved TT performance and Hbmass in elite AF players to a magnitude similar to that demonstrated by elite endurance athletes undertaking altitude training. The individual responsiveness of both TT and Hbmass was approximately half the group mean effect, indicating that most players gained benefit. The maintenance of running performance for 4 wk, despite Hbmass returning to baseline, suggests that altitude training is a valuable preparation for AF players leading into the competitive season.
Collapse
|
69
|
Wachsmuth NB, Völzke C, Prommer N, Schmidt-Trucksäss A, Frese F, Spahl O, Eastwood A, Stray-Gundersen J, Schmidt W. The effects of classic altitude training on hemoglobin mass in swimmers. Eur J Appl Physiol 2012; 113:1199-211. [PMID: 23138148 DOI: 10.1007/s00421-012-2536-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 10/20/2012] [Indexed: 10/27/2022]
Abstract
Aim of the study was to determine the influence of classic altitude training on hemoglobin mass (Hb-mass) in elite swimmers under the following aspects: (1) normal oscillation of Hb-mass at sea level; (2) time course of adaptation and de-adaptation; (3) sex influences; (4) influences of illness and injury; (5) interaction of Hb-mass and competition performance. Hb-mass of 45 top swimmers (male 24; female 21) was repeatedly measured (~6 times) over the course of 2 years using the optimized CO-rebreathing method. Twenty-five athletes trained between one and three times for 3-4 weeks at altitude training camps (ATCs) at 2,320 m (3 ATCs) and 1,360 m (1 ATC). Performance was determined by analyzing 726 competitions according to the German point system. The variation of Hb-mass without hypoxic influence was 3.0 % (m) and 2.7 % (f). At altitude, Hb-mass increased by 7.2 ± 3.3 % (p < 0.001; 2,320 m) and by 3.8 ± 3.4 % (p < 0.05; 1,360 m). The response at 2,320 m was not sex-related, and no increase was found in ill and injured athletes (n = 8). Hb-mass was found increased on day 13 and was still elevated 24 days after return (4.0 ± 2.7 %, p < 0.05). Hb-mass had only a small positive effect on swimming performance; an increase in performance was only observed 25-35 days after return from altitude. In conclusion, the altitude (2,320 m) effect on Hb-mass is still present 3 weeks after return, it decisively depends on the health status, but is not influenced by sex. In healthy subjects it exceeds by far the oscillation occurring at sea level. After return from altitude performance increases after a delay of 3 weeks.
Collapse
Affiliation(s)
- N B Wachsmuth
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, 95440 Bayreuth, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
70
|
Increased hemoglobin mass and VO2max with 10 h nightly simulated altitude at 3000 m. Int J Sports Physiol Perform 2012; 8:366-72. [PMID: 23118056 DOI: 10.1123/ijspp.8.4.366] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE To quantify the changes of hemoglobin mass (Hbmass) and maximum oxygen consumption (VO2max) after 22 days training at 1300-1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h. METHODS Fourteen male collegiate runners were equally divided into 2 groups: altitude (ALT) and control (CON). Both groups spent 22 days at 1300-1800 m. ALT spent 10 h/night for 21 nights in simulated altitude (3000 m), and CON stayed at 1300 m. VO2max and Hbmass were measured twice before and once after the intervention. Blood was collected for assessment of percent reticulocytes (%retics), serum erythropoietin (EPO), ferritin, and soluble transferrin receptor (sTfR) concentrations. RESULTS Compared with CON there was an almost certain increase in absolute VO2max (8.6%, 90% confidence interval 4.8-12.6%) and a likely increase in absolute Hbmass (3.5%; 0.9-6.2%) at postintervention. The %retics were at least very likely higher in ALT than in CON throughout the 21 nights, and sTfR was also very likely higher in the ALT group until day 17. EPO of ALT was likely higher than that of CON on days 1 and 5 at altitude, whereas serum ferritin was likely lower in ALT than CON for most of the intervention. CONCLUSIONS Together the combination of the natural and simulated altitude was a sufficient total dose of hypoxia to increase both Hbmass and VO2max.
Collapse
|
71
|
Garvican LA, Saunders PU, Pyne DB, Martin DT, Robertson EY, Gore CJ. Hemoglobin mass response to simulated hypoxia "blinded" by noisy measurement? J Appl Physiol (1985) 2012; 112:1797-8; author reply 1799. [PMID: 22589495 DOI: 10.1152/japplphysiol.00212.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
72
|
Schumacher YO, Klodt F, Nonis D, Pottgiesser T, Alsayrafi M, Bourdon PC, Voss SC. The impact of long-haul air travel on variables of the athlete's biological passport. Int J Lab Hematol 2012; 34:641-7. [DOI: 10.1111/j.1751-553x.2012.01450.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Accepted: 05/03/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Y. O. Schumacher
- Department of Sports Medicine; University of Freiburg; Freiburg Germany
| | - F. Klodt
- Department of Sports Medicine; University of Freiburg; Freiburg Germany
| | - D. Nonis
- Department of Sports Medicine; University of Freiburg; Freiburg Germany
| | - T. Pottgiesser
- Department of Sports Medicine; University of Freiburg; Freiburg Germany
| | | | | | | |
Collapse
|
73
|
POTTGIESSER TORBEN, ECHTELER TOBIAS, SOTTAS PIERREEDOUARD, UMHAU MARKUS, SCHUMACHER YORCKOLAF. Hemoglobin Mass and Biological Passport for the Detection of Autologous Blood Doping. Med Sci Sports Exerc 2012; 44:835-43. [DOI: 10.1249/mss.0b013e31823bcfb6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
74
|
Short-Term Hematological Effects Upon Completion of a Four-Week Simulated Altitude Camp. Int J Sports Physiol Perform 2012; 7:79-83. [DOI: 10.1123/ijspp.7.1.79] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Hemoglobin mass (tHb) is considered to be a main factor for sea-level performance after “live high–train low” (LHTL) altitude training, but little research has focused on the persistence of tHb following cessation of altitude exposure. The aim of the case study was to investigate short-term effects of various hematological measures including tHb upon completion of a simulated altitude camp. Five female cyclists spent 26 nights at simulated altitude (LHTL, 16.6 ± 0.4 h/d, 3000 m in an altitude house) where tHb was measured at baseline, at cessation of the camp, and 9 d thereafter. Venous blood measures (hemoglobin concentration, hematocrit, %reticulocytes, serum erythropoietin, ferritin, lactate dehydrogenase, and haptoglobin) were determined at baseline; on day 21 during LHTL; and at days 2, 5, and 9 after LHTL. Hemoglobin mass increased by 5.5% (90% confidence limits [CL] 2.5 to 8.5%, very likely) after the LHTL training camp. At day 9 after simulated LHTL, tHb decreased by 3.0% (90%CL −5.1 to −1.0%, likely). There was a substantial decrease in serum EPO (−34%, 90%CL −50 to −12%) at 2 d after return to sea level and a rise in ferritin (23%, 90%CL 3 to 46%) coupled with a decrease in %reticulocytes (−23%, 90%CL −34 to −9%) between day 5 and 9 after LHTL. Our findings show that following a hypoxic intervention with a beneficial tHb outcome, there may be a high probability of a rapid tHb decrease upon return to normoxic conditions. This highlights a rapid component in red-cell control and may have implications for the appropriate timing of altitude training in relation to competition.
Collapse
|