FrankDay said:
PED's improve power and endurance because they improve oxygen delivery. They have never been shown to improve cycling efficiency. Try again.
Intermittent Hypoxia Improves Endurance Performance
and Submaximal Exercise Efficiency
ABSTRACT
Katayama, Keisho, Hiroshi Matsuo, Koji Ishida, Shigeo Mori, and Miharu Miyamura. Intermittent hypoxia improves endurance performance and submaximal exercise efficiency. High Alt Med Biol 4:291–304, 2003.—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 5 6) or a control group (n 5 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 (VO2) 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 VO2 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.
Live high: train low increases muscle buffer capacity and submaximal cycling efficiency
CJ Gore, AG Hahn, RJ Aughey… - Acta physiologica …, 2008 - Wiley Online Library
This study investigated whether hypoxic exposure increased muscle buffer capacity (βm) and mechanical efficiency during exercise in male athletes. A control (CON, n=7) and a live high:train low group (LHTL, n=6) trained at near sea level (600 m), with the LHTL group sleeping for 23 nights in simulated moderate altitude (3000 m). Whole body oxygen consumption (V˙o2) was measured under normoxia before, during and after 23 nights of sleeping in hypoxia, during cycle ergometry comprising 4×4-min submaximal stages, 2-min at 5.6 ± 0.4 W kg–1, and 2-min ‘all-out’ to determine total work and V˙o2peak. A vastus lateralis muscle biopsy was taken at rest and after a standardized 2-min 5.6 ± 0.4 W kg–1 bout, before and after LHTL, and analysed for βm and metabolites. After LHTL, βm was increased (18%, P < 0.05). Although work was maintained, V˙o2peak fell after LHTL (7%, P < 0.05). Submaximal V˙o2 was reduced (4.4%, P < 0.05) and efficiency improved (0.8%, P < 0.05) after LHTL probably because of a shift in fuel utilization. This is the first study to show that hypoxic exposure, per se, increases muscle buffer capacity. Further, reduced V˙o2 during normoxic exercise after LHTL suggests that improved exercise efficiency is a fundamental adaptation to LHTL.
Altitude training for improved performance at sea level remains highly contentious (Rusko 1996, Saltin 1996, Wolski et al. 1996). In part, this may be a consequence of any performance change being small and variable between individuals (Rusko 1996). Recently an alternative approach to enhance athletic performance has been mooted, where athletes live at moderate altitude and train near sea level. This method of using hypobaric hypoxia improved the sea-level 5000 or 3000 m run time in both college (Levine & Stray-Gundersen 1997) and elite level runners (Stray-Gundersen et al. 2001), but enhanced performance is a relatively rare outcome among those studies of altitude training that have used a control (CON) group. Because many countries lack suitable geography, the so-called ‘live high:train low’ (LHTL) approach (Levine & Stray-Gundersen 1997) has been further refined to include living at simulated altitude under normobaric conditions (Rusko 1996).
Regardless of whether LHTL or natural altitude sojourns are used by athletes there is some evidence to challenge the traditional paradigm that the key adaptation for any performance benefit is increased red cell mass (Mairbäurl 1994) and the concomitant increase in maximal aerobic power (V˙o2max) that has otherwise been associated with polycythaemia (Buick et al. 1980). Two studies have reported that training at altitude (˜2000–2700 m) induced a 5–6% increase in skeletal muscle in-vitro buffer capacity (βm) (Mizuno et al. 1990, Saltin et al. 1995a). Furthermore, a carefully conducted study has recently reported a significant (5%) improvement in the net mechanical efficiency of submaximal cycling subsequent to a 21-day mountain ascent (6194 m) (Green et al. 2000b). The mechanism of increased βm and mechanical efficiency is unclear, but in both cases hypoxia is a likely candidate.
Given the potential importance of anaerobic metabolism (Bulbulian et al. 1986) and efficiency (Snell & Mitchell 1984) to performance, even in highly trained endurance athletes, further investigation of possible anaerobic adaptations to hypoxia is clearly warranted. Based on the reported effect of 2 weeks living and training at natural altitude (Saltin et al. 1995a), we hypothesized that merely sleeping in moderate hypoxia (LHTL) for sufficient duration would improve βm. Secondly, based on the observation of Green et al. (2000b), we hypothesized that LHTL of sufficient duration would improve gross mechanical efficiency during submaximal cycle ergometry conducted in normobaric normoxia.
And many others that would suggest that improving oxygen delivery through using EPO or altitude training improves cycling efficiency.
Of course, the duration and intensity of the training must be enough to overcome and correct these deficiencies. That is where the argument is, me thinks.
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