Relationship of age and exercise performance in patients with heart failure: the HF-ACTION study.
                             
                            
                            
                                
                            
                            
                                
                            
                            
                            
                                
                                    
                                            
    Forman DE, Clare R, Kitzman DW, Ellis SJ, Fleg JL, Chiara T, Fletcher G, Kraus WE. Relationship of age and exercise performance in patients with heart failure: the HF-ACTION study. Am Heart J. 2009 Oct; 158(4 Suppl):S6-S15.