Live-High Train-Low Altitude Training on Maximal Oxygen Consumption in Athletes: A Systematic Review and Meta-Analysis

Abstract

INTRODUCTION Lancaster and Smart have provided us with an altitude training / hypoxic exposure metaanalysis, which includes a group of 11 studies utilizing a wide variety of hypoxia delivery mechanisms, exposure times, and subject cohorts. Meta-analysis is a quantitative analysis of the results of individual empirical studies [1] and is often used as a means to review previous studies, test theoretical propositions, and/or make generalizations about an entire population. Meta-analysis can be quite useful and is utilized in a number of fields, most prominently in medicine [2]. However, meta-analysis is not without limitations. With any meta-analysis, there is an underlying assumption that the combined studies share commonalities, particularly with regard to components such as treatments, subject characteristics, and measurements. If these components are quite similar, then a meta-analysis can be a helpful tool. However, if the studies under consideration have fundamental differences in experimental design or underlying physiological rationale, then a meta-analysis may in fact just be combining noise, ultimately comparing apples and oranges. In giving weight to the Lancaster and Smart analysis, the reader should be fully aware of some of the many issues involved with training studies in general and altitude training / hypoxic exposure studies in particular [3], many of which go well beyond the limitations noted by the authors in their paper. Each of these issues, if not controlled for, can add substantial variability to the outcome measures being examined. Additionally, there are substantial differences in both the research methodologies and hypoxic doses used in the studies utilized in this particular meta-analysis. We question if it is useful and proper to compare the outcomes of these studies to each other under a global umbrella of “Live High – Train Low.” Each of these theoretical issues is addressed below.