Impact of Sex on Cardiovascular Adaptations to Exercise: JACC Review Topic of the Week.

Routine exercise leads to cardiovascular adaptations that differ based on sex. Use of cardiac testing to screen athletes has driven research to define how these sex-based adaptations manifest on the electrocardiogram and cardiac imaging. Importantly, sex-based differences in cardiovascular structure and outcomes in athletes often parallel findings in the general population, underscoring the importance of understanding their mechanisms. Substantial gaps exist in the understanding of why cardiovascular adaptations and outcomes related to exercise differ by sex because of underrepresentation of female participants in research. As female sports participation rates have increased dramatically over several decades, it also remains unknown if differences observed in older athletes reflect biological mechanisms vs less lifetime access to sports in females. In this review, we will assess the effect of sex on cardiovascular adaptations and outcomes related to exercise, identify the impact of sex hormones on exercise performance, and highlight key areas for future research.

Sex-biased phoretic mite load on two seaweed flies: Coelopa frigida and Coelopa pilipes.

Two hypotheses explain male-biased parasitism. Physiological costs of male sexually selected characteristics can reduce immunocompetence. Alternatively, ecological differences could generate male-biased parasitism. One method of comparing the importance of the two theories is to investigate patterns of phoresy, which are only likely to be generated by ecological rather than immunological differences between the sexes. Here we studied the pattern of phoresy of the mite, Thinoseius fucicola, on two species of seaweed fly hosts, Coelopa frigida and Coelopa pilipes. We found a highly male-biased pattern of phoresy of T. fucicola on both species. These are the first reported instances of sex-biased phoresy in a solely phoretic parasite. We also show the first two cases of size-biased phoresy. We suggest that ecological factors, particularly, male mate searching, generated male biased patterns of phoresy. We highlight the potential importance of studies of phoresy in determining the relative roles of the immunocompetence and ecological theories in generating male-biased parasitism. We suggest that more studies of patterns of phoresy are carried out to allow detailed comparisons with patterns of parasitism.