Listen to Your Heart

Here's a neat study that utilizes heart rate variability for endurance training.  When heart rate variability increases or stayed the same, high-intensity training was prescribed.  When heart rate variability decreased, rest or low-intensity training was prescribed.

Over the course of the study, the group that used their heart rate variability information increased VO2max, while the control group had no change in VO2max.  This study shows that listening to your body pays dividends.