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Bassovitch O. Combining hypoxic methods for peak performance: a biomedical engineering perspective.Sports Med. 2010 Jun 1;40(6):519-21; author reply 521-3 Bassovitch O. Intermittent hypoxic training: risks versus benefits. A biomedical engineering point of view.Eur J Appl Physiol. 2010 Jun 5. Bassovitch, Oleg; Tatiana V. Serebrovskaya (2010) Equipment and Regimes for Intermittent Hypoxia Therapy. M.J. Hamlin and J. Hellemans. Presented at 51st ANNUAL MEETING American College of Sports Medicine
Simulated-altitude training devices have become a popular and relatively inexpensive alternative to travelling to altitude, however beneficial effects and possible underlying mechanisms of such devices are contentious. PURPOSE: To investigate the effect of intermittent normobaric
hypoxic exposure on selected blood parameters. RESULTS: Substantial increases resulting from IHT were unlikely for haemoglobin at day 2 (0.2±3.2%, mean change between groups as a percentage ± 95% confidence limit) but possible by day 12 (2.5±4.2) after exposure. However, substantial increases resulting from IHT in hematocrit (1.5±3.1 day 2 and 3.6±4.1 day 12) and reticulocytes (23.5±21.1 day 2 and 14.6±21.7 day 12) were much more likely. Substantial decreases resulting from IHT exposure were highly likely for serum iron (-45.8±38.2 day 2 and -80.4±41.8 day 12) and possible for ferritin (-16.9±19.7 day 2 and -9.9±21.2 day 12). Effects of IHT on mean cell volume and mean cell haemoglobin were trivial. CONCLUSION: Intermittent hypoxic training can elicit changes in haematological indices that suggest an acceleration of erythropoiesis. Supported by the Canterbury Medical Research Foundation. Full-size poster available to download (1.5MB PDF): Katayama K, Matsuo H, Ishida K, Mori S, Miyamura M. Intermittent hypoxia improves endurance performance and submaximal exercise efficiency. High Alt Med Biol. 2003 Fall;4(3):291-304. Related Articles Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya 464-8601, Japan. katayama@htc.nagoya-u.ac.jp The purpose of the present study was to elucidate the influence of intermittent hypobaric hypoxia at rest on endurance performance and cardiorespiratory and hematological adaptations in trained endurance athletes. Twelve trained male endurance runners were assigned to either a hypoxic group (n = 6) or a control group (n = 6). The subjects in the hypoxic group were exposed to a simulated altitude of 4500 m for 90 min, three times a week for 3 weeks. The measurements of 3000 m running time, running time to exhaustion, and cardiorespiratory parameters during maximal exercise test and resting hematological status were performed before (Pre) and after 3 weeks of intermittent hypoxic exposure (Post). These measurements were repeated after the cessation of intermittent hypoxia for 3 weeks (Re). In the control group, the same parameters were determined at Pre, Post, and Re for the subjects not exposed to intermittent hypoxia. The athletes in both groups continued their normal training together at sea level throughout the experiment. In the hypoxic group, the 3000 m running time and running time to exhaustion during maximal exercise test improved. Neither cardiorespiratory parameters to maximal exercise nor resting hematological parameters were changed in either group at Post, whereas oxygen uptake (.V(O2)) during submaximal exercise decreased significantly in the hypoxic group. After cessation of intermittent hypoxia for 3 weeks, the improved 3000 m running time and running time to exhaustion tended to decline, and the decreased .V(O2) during submaximal exercise returned to Pre level. These results suggest that intermittent hypoxia at rest could improve endurance performance and submaximal exercise efficiency at sea level in trained endurance athletes, but these improvements are not maintained after the cessation of intermittent hypoxia for 3 weeks. M.J. Hamlin and J. Hellemans Reported at Australian Conference of Science and Medicine in Sport. October 25-28 2003 National Convention Centre Canberra. Currently IN PRESS. This investigation demonstrated that the use of intermittent normobaric hypoxia in 5 minute intervals for 90 minutes a day, 5 days per week for 3 weeks is sufficient to elicit significant and worthwhile improvements in 3-km performance in well-trained subjects. We have also demonstrated that such an IHT protocol can elicit changes in haematological indices that suggest an acceleration of erythropoiesis. However, the 10-min hypoxic test found only a moderate correlation with subsequent performance enhancement, and is probably not a useful test to determine responders to simulated altitude training from non-responders. It is also important to note that while subjects are using IHT their total training stress increases and risks of overtraining and poor performance may develop if not managed appropriately. Proceeding from the Gatorade International Triathlon Science II Conference. Noosa, Australia, Nov. 7-8, 1999. Intermittent Hypoxic Training: A pilot Study. Hellemans J. Charlotte C Harrison, Jenny M Fleming, Lynn C Gilles Charlotte C Harrison, Jenny M Fleming, Lynn C Gilles |
