Hypobaric live high‐train low does not improve aerobic performance more than live low‐train low in cross‐country skiers

Abstract

Live high-train low (LHTL) using hypobaric hypoxia was previously found to improve sea-level endurance performance in well-trained individuals; however, confirmatory controlled data in athletes are lacking. Here, we test the hypothesis that natural-altitude LHTL improves aerobic performance in cross-country skiers, in conjunction with expansion of total hemoglobin mass (Hb , carbon monoxide rebreathing technique) promoted by accelerated erythropoiesis. Following duplicate baseline measurements at sea level over the course of 2 weeks, nineteen Norwegian cross-country skiers (three women, sixteen men, age 20 ± 2 year, maximal oxygen uptake (VO max) 69 ± 5 mL/min/kg) were assigned to 26 consecutive nights spent at either low (1035 m, control, n = 8) or moderate altitude (2207 m, daily exposure 16.7 ± 0.5 hours, LHTL, n = 11). All athletes trained together daily at a common location ranging from 550 to 1500 m (21.2% of training time at 550 m, 44.2% at 550-800 m, 16.6% at 800-1100 m, 18.0% at 1100-1500 m). Three test sessions at sea level were performed over the first 3 weeks after intervention. Despite the demonstration of nocturnal hypoxemia at moderate altitude (pulse oximetry), LHTL had no specific effect on serum erythropoietin, reticulocytes, Hb , VO max, or 3000-m running performance. Also, LHTL had no specific effect on (a) running economy (VO assessed during steady-state submaximal exercise), (b) respiratory capacities or efficiency of the skeletal muscle (biopsy), and (c) diffusing capacity of the lung. This study, showing similar physiological responses and performance improvements in the two groups following intervention, suggests that in young cross-country skiers, improvements in sea-level aerobic performance associated with LHTL may not be due to moderate-altitude acclimatization.

Hematological Adaptations to Prolonged Heat Acclimation in Endurance-Trained Males

“…The strong association between endurance performance and Hb mass implies that strategies to stimulate and induce an overall increase in Hb mass are commonly applied by endurance athletes (Gore et al, 1997). A classic procedure is altitude training or “live high-train low”, where the hypoxia-induced augmented RBCV is observed to enhance performance (Stray-Gundersen and Levine, 2008), although more recent evidence questions this approach (Bejder and Nordsborg, 2018; Robach et al, 2018). Nonetheless, data showing Hb mass expansion with altitude training in individuals with a similarly high Hb mass as in the present study, report an increase of 5–6% (Robach and Lundby, 2012), which is slightly higher than the +3% observed in the current study with prolonged exercise-heat acclimation.…”

Determinants of maximal whole‐body fat oxidation in elite cross‐country skiers: Role of skeletal muscle mitochondria

“…All cross‐country skiers had participated in competitions at national elite level in Norway as juniors and now as seniors (from the age of 20). The present article includes data from two prior studies investigating the effect of altitude training in endurance athletes and bed rest in untrained subjects, respectively. The study on endurance athletes included a total of 19 subjects, whereas the study on untrained included 15 subjects.…”

“…The study including the endurance athletes was conducted from June‐August 2015 in Lillehammer in Norway and in Chamonix in France, whereas the study including the untrained subjects was conducted from January‐February 2016 in Zürich in Switzerland. As the mitochondrial respiratory analyses were done on fresh muscle tissue in both studies, and because part of these data was also published in Robach et al, the mitochondrial respiratory capacities of the endurance athletes were known before the study on untrained subjects was initiated.…”

Maximizing Cellular Adaptation to Endurance Exercise in Skeletal Muscle

“…As no muscle biopsies were taken in that investigation, it was impossible to determine if the different altitude-training regimens resulted in changes in hypoxia-mediated signaling pathways, or if there were changes in major training-induced signaling proteins. Indeed, justification for the LHTL practice has recently been challenged (Lundby and Robach, 2016;Robach et al, 2018). While training in a hypoxic environment (LLTH), at least in the short-term, leads to a decrease in the absolute intensity of training, this has no negative influence on the overall training response in terms of improvements in VO 2max Robach et al, 2014;Ventura et al, 2003;Vogt et al, 2001), and the initial rationale proposed to advocate LHTL seems premature.…”