I’m a 51yr old male, new to cycling but a seasoned endurance runner (10km+ distances). I started training with The Sufferfest in November as part of recovering from a running injury.
I took my first 4DP test in February, and my second yesterday (mid-May). Clearly my fitness has improved enormously since starting out. Over the past 3 months my FTP and MAP numbers have increased by more than 20 points, but my lactate threshold heart rate (LTHR) has dropped from 161 to 158.
I would have expected my LTHR to rise as my aerobic capacity improved. I feel fitter and can see the improvements in my workouts. So why has my LTHR dropped? Physiologically what is happening?