In particular, patients with HFrEF compared to PAD and CAD patients benefit more from this type of exercise irrespective of EPC phenotype (CD34+/KDR+, CD34+/KDR+/CD45dim, CD34+/KDR+/CD31+) and duration of the intervention (3–12 weeks) which is in line with previous meta-analyses (Pearson and Smart 2017; Cavalcante et al. 2019). Here, CD34 is linked to coronary artery disorder.