About this Research Topic
Numerous observational and interventional studies provide convincing evidence that regular exercise is a powerful, safe, and cost-effective intervention against morbidity and mortality from chronic diseases, as well as the detrimental effects of aging. In contrast, physical inactivity and a sedentary lifestyle exert a negative impact on health. It is because of this overwhelming evidence that exercise is advocated as medicine. Exercise regimens used to fight chronic disease generally fall under three categories: moderate-intensity continuous training, resistance training, and interval training. Several parameters within each category produce numerous combinations to choose from. If exercise is medicine, then these combinations may be viewed as an armamentarium of different medications.
The question then arises: Which exercise “medication” should we prescribe to a patient? While prescription of literal medications is founded on solid grounds of diagnostic criteria, this is less certain in the case of exercise. What is more, there is great interindividual variability in the responses to training, reaching the extent of no positive or even adverse outcomes in some individuals. The practical question arising from such findings is what to do with non-responders. Should we relinquish exercise as a therapeutic agent for them? Or could a non-responder to a particular type of training be a responder to another? This question has not been adequately addressed, although limited evidence suggests that if a certain type of exercise does not work for an individual, another type may. Naturally, it would be highly desirable to know the kind of training that is beneficial for each individual in advance rather than discover it through trial and error.
So, what explains the variability in the responses to training? The first thing that may come to mind is genetics. A number of genomic studies have shown associations of specific gene variants with the effects of training on health-related outcomes. However, these findings remain weakly supported, as replication studies are lacking. Things are even less clear when one moves from the genotype to the phenotype, that is, at the levels of the transcriptome, proteome, and metabolome. Few studies have put the powers of transcriptomics, proteomics, and metabolomics at the service of differentiating responders from non-responders to training programs.
On the basis of this brief analysis, the necessity arises for predictive biomarkers of the responses to training, which will serve the long-term vision of successful exercise prescription. The scientific community needs to rise to this challenge. It is no longer acceptable to acknowledge the problem of interindividual variability in the responses to training; we need to deal with it.
Thus, the aims of this Research Topic are to:
• Welcome original contributions from researchers who have explored predictive biomarkers of the responses to various training regimes;
• Attract narrative reviews, systematic reviews, or meta-analysis summarizing and critically assessing the state-of-the-art on the subject;
• Encourage further research in the area;
• Foster a fruitful discussion around the subject from a variety and, hopefully, combination of perspectives (genomic, transcriptomic, proteomic, and metabolomic).
Keywords: exercise training, interindividual variability, genomics, proteomics, metabolomics
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