RT Journal Article SR Electronic T1 Run for your life … at a comfortable speed and not too far JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 516 OP 519 DO 10.1136/heartjnl-2012-302886 VO 99 IS 8 A1 O'Keefe, James H A1 Lavie, Carl J YR 2013 UL http://heart.bmj.com/content/99/8/516.abstract AB