Change in Submaximal Cardiorespiratory Fitness and All-Cause Mortality

To evaluate the relationship between change in submaximal cardiorespiratory fitness (sCRF) and all-cause mortality risk in adult men and women.A prospective study with at least 2 clinical visits (mean follow-up time, 4.2±3.0 years) between April 1974 and January 2002 was conducted to assess the relationship between change in sCRF and mortality risk during follow-up. Participants were 6106 men and women. Submaximal CRF was determined using the heart rate obtained at the 5-minute mark of a graded maximal treadmill test used to determine maximal CRF (mCRF). Change in sCRF from baseline to follow-up was categorized into 3 groups: increased fitness (decreased heart rate, 3.0 beats/min).The mean change in sCRF at follow-up for all 6106 study participants was\ua0-0.5±10.0 beats/min, and the mean change in mCRF was\ua0-0.3±1.4 metabolic equivalents. Change in sCRF was related to change in mCRF, though the variance explained was small (R2=0.21;