Hitonobu Tomoike

1. Introduction Cardiac rehabilitation (CR) is an evidence-based, class I, guideline-recommended secondary prevention strategy for many cardiovascular conditions among international guidelines [1,2,3]. Exercise assessment and prescription based on cardiopulmonary exercise testing (CPET) are core components of CR programs [4,5,6]. Improvements in cardiorespiratory fitness through long-term CR reduce rates of hospitalization and mortality in apparently healthy and clinical populations [7,8,9,10].

In this issue of Circulation Research, Shimokawa et al1 report that the number of scientific publications submitted from Japan to the American Heart Association journals recently has dropped impressively compared with just 17 years ago (from 164 papers in 2000 down to only 45 in 2016), when Japan published more papers than any other country except for the United States and Germany.