Physical activity is remarkable medicine. The 2018 Physical Activity Guidelines for Americans reported 27 major physical and mental health benefits with strong research support, all of which are compelling (eg, lower all-cause mortality). Among these benefits, 9 were denoted as new for 2018. These new benefits are, of course, not new in the sense that active people in the past did not receive them; rather, they are new in the sense that sufficient evidence arose in meta-analyses to affirm them. In their systematic review and meta-analysis published in this issue of JAMA Pediatrics, Recchia et al extend the evidence on health benefits of physical activity. Their meta-analysis includes data from more than 2400 youth who participated in more than 20 randomized clinical trial and quasi-experimental design studies. The review includes data collected by researchers in the US, China, Chile, Germany, Iran, Brazil, Thailand, and the UK over the past 35 years (though the majority were conducted in the past 10 years). The work is timely, aligning with the rise of mental health disorders in adolescents, and the methods are rigorous (eg, random-effects models, risk-of-bias assessment, sensitivity analyses).