“Live high, train low” does not change the total haemoglobin mass of male endurance athletes sleeping at a simulated altitude of 3000 m for 23 nights

Abstract

The purpose of this study was to document the effect of 23 days of "live high, train low" on the haemoglobin mass of endurance athletes. Thirteen male subjects from either cycling, triathlon or cross-country skiing backgrounds participated in the study. Six subjects (HIGH) spent 8-10 h per night in a "nitrogen house" at a simulated altitude of 3000 m in normobaric hypoxia, whilst control subjects slept at near sea level (CONTROL, n = 7). Athletes logged their daily training sessions, which were conducted at 600 m. Total haemoglobin mass (as measured using the CO-rebreathing technique) did not change when measured before (D1 or D2) and after (D28) 23 nights of hypoxic exposure [HIGH 990 (127) vs 972 (97) g and CONTROL 1042 (133) vs 1033 (138) g, before and after simulated altitude exposure, respectively]. Nor was there any difference in the substantial array of reticulocyte parameters measured using automated flow cytometry prior to commencing the study (D1), after 6 (D10) and 15 (D19) nights of simulated altitude, or 1 day after leaving the nitrogen house (D28) when HIGH and CONTROL groups were compared. We conclude that red blood cell production is not stimulated in male endurance athletes who spend 23 nights at a simulated altitude of 3000 m.

Intermittent Hypoxic Training: Fact and Fancy

“…Moreover, it is important to recognize that short-term exposure to acute hypoxia may increase hematocrit and hemoglobin concentration by hemoconcentration and may increase reticulocyte counts by release of immature red cell forms from the bone marrow, without a true acceleration of erythropoiesis (Gunga et al, 1996). Some investigators, failing to observe an increase in hemoglobin-myoglobin mass after brief periods of time in normobaric hypoxic environments (8 to 10 h/night for 10 d for 3 weeks) have questioned the erythropoietic effect of moderate altitude exposure altogether (Ashenden et al, 1999a(Ashenden et al, , 1999b(Ashenden et al, , 2000, and it seems certain from these data that, under the 180 LEVINE specific conditions of these experiments, sleeping in a nitrogen-enriched environment may in fact not be erythropoietic. Although short-duration exposures of less than 10 h for less than 3 weeks do not raise red cell mass in the Australian experience (Ashenden et al, 1999a(Ashenden et al, , 1999b(Ashenden et al, , 2000, Finnish investigators have been able to demonstrate increases in red cell mass (using the same technique, carbon monoxide rebreathing, as the Australian investigators using shorter-term exposures) with 16 h of hypoxia/night for 4 weeks (Laitinen et al, 1995;Rusko et al, 1999).…”

Effects of Intermittent Altitude Exposures on Acclimatization of 4,300 M

“…Group resting and maximal P0 2 remained unchanged from PreAc to PostAc. Both resting and maximal PC0 2 and [HC0 3 " 1 ] were decreased from PreAc to PostAc in both groups. When data from both groups were combined, maximal pH was decreased, resting and maximal P0 2 remained unchanged, resting and maximal PC0 2 were decreased, and resting and maximal [HC0 3 " 1 ] were decreased from PreAc to PostAc.…”

“…Bicarbonate concentration [HC0 3 "] was caculated using the Henderson-Hasselbach equation. Base excess [BE] was calculated from a standard nomogram (97).…”

“…Thus, the improvements in exercise performance under these circumstances are most likely related to the wellknown beneficial effects of exercise training rather than the adaptations that occur with altitude acclimatization. Similarly, the effects of exercise training while residing at altitude for a significant portion of the day (i.e., sleep high, train low) have been extensively reviewed (29,112) and although controversial (3)(4)(5) suggest that living high (i.e >16 h-d" 1 ), training low improves post-altitude sea level performance due to increases in red blood cell mass and maintenance of training intensity (58,100).…”

O desafio da altitude. Uma perspectiva fisiológica

“…Da mesma forma, embora a altitudes moderadas, os investigadores têm procurado descrever as adaptações orgânicas induzidas pelo denominado treino em atitude, procurando interpretar o seu real contributo para a melhoria do desempenho em altitude e, particularmente, ao nível do mar. Neste último domínio da investigação, para além dos muitos estudos de terreno (5,9,44,71), também tem sido desenvolvida abundante investigação laboratorial (2,3,50). Nos estudos laboratoriais, têm sido utilizadas câma-ras com ambiente interior hermeticamente controlado para simular condições de altitude.…”