Abstract

Life history theory predicts the existence of trade-offs between competing physiological functions relating to reproduction, maintenance, defence, growth and storage under conditions of limited environmental resources. This results in an individual may allocate energy to traits enhancing fertility or invest in traits enhancing survivorship. Despite the intuitive appeal of a stereotypical trade-off featuring a negative relationship between two traits, such negative covariation of traits are frequently absent when phenotypic comparisons are made between individuals in a population. Research within the ADaPt Project uses ultra-marathon competitions as quasi-experimental scenarios intended to induce an energy deficit. This allows negative correlations to be observed, enabling study of human life history trade-offs. Here, I will discuss our analysis of athletes’ physiological response to competition across a range of extreme environments, and present the findings of previous pilot work.