Relationships between gut microbiome perturbation and autism spectrum disorder (ASD) have been observed in several human studies, but the functional implications and molecular mechanisms by which microbes may influence disease symptomology remain enigmatic. A recently published study by Sharon et al. offers evidence that the gut microbiome has a causative role in ASD and highlights the importance of early-life gut microbial metabolites in shaping mammalian behavior.
In recent years, high-intensity interval training (HIIT) has gained prominence in the health and fitness area, becoming a worldwide trend. Given the positive results of HIIT, researchers have compared it with moderate-intensity continuous training (MICT). However, much of that research has presented methodological challenges. Therefore, the aim of this opinion article is to address an important risk of bias common in research comparing HIIT and MICT: the lack of equalisation among protocols. This limitation can be considered a risk of bias that limits the conclusions of many studies.